Service Manual2005 Diagnostic Trouble Code (DTC) P0131

Matiz

Diagnostic Trouble Code (DTC) P0131

Front Heated Oxygen Sensor Low Voltage

Circuit Description

The engine control module (ECM) supplies a voltage of about 450mm volts between the ECM terminals 44 and 13. The oxygen (O2) sensor varies the voltage within a range of about 1volt if the exhaust is rich, down to about 100mm volts if the exhaust is lean. The O2 sensor is like an open circuit and produces no voltage when it is below 360°C(600°F). An open O2 sensor circuit or a cold O2 sensor causes "open loop" operation.

Conditions for Setting the DTC

(Case A)

The engine controls system is in closed loop.
Engine speed is less than 6,000rpm.
The oxygen sensor voltage is below 0.07V for at least 40seconds.
DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0335, P0336, P0341, P0342, P0400, P0404, P0405, P0406 are NOT SET.

(Case B)

The engine controls system is in closed loop.
Engine speed is less than 6,000rpm.
The oxygen sensor voltage is between 0.352 and 0.499 at least 10 seconds.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.
The coolant fan turns ON.

Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm-up cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Disconnecting the ECM battery feed for more than 10 seconds.

Diagnostic Aids

Normal scan tool voltage varies between 0.1volts and 0.9 volts while in closed loop.

Inspect the oxygen (O2) sensor wire. The O2 sensor may be positioned incorrectly and contacting the exhaust manifold.

Check for an intermittent ground in the wire between the O2 sensor and the engine control module.

Perform an injector 2alance test to determine if a restricted fuel injector may be causing the lean condition.

Vacuum of crankcase leaks will cause a lean running condition.

An exhaust manifold gasket leak of a cracked exhaust manifold may cause outside air to be pulled into the exhaust and past the sensor.

DTC P0131 - Front Heated Oxygen Sensor Low Voltage

Step	Action	Value(s)	Yes	No
1	Perform an Euro On-Board Diagnostic (EOBD) System Check. Is the system check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Connect the scan tool to the data link connector (DLC). Run the engine until it reaches operating temperature. Check for closed loop operation. Does the engine control module(ECM) go into closed loop?	-	Go to Step 3	Go to Step 9
3	Run the until until it reaches operating temperature? Run the engine at 1,200rpm. Does the scan tool read the upstream oxygen(O2 ) sensor signal voltage between the valve specified?	0.25~0.65V	Go to Step 5	Go to Step 4
4	Does the scan tool read the Oxygen sensor signal voltage fixed below the valve specified?	0.01V	Go to Step 7	Go to "Diagnostic Aids"
5	Disconnect the Oxygen sensor connector. Run the warm engine at idle. Does the scan tool read the Oxygen sensor signal voltage between the valve specified?	0.25~0.65V	Go to "Diagnostic Aids"	Go to Step 6
6	Turn the ignition switch to LOCK. Check the Oxygen sensor wire between the Oxygen sensor and the ECM connector terminal 44 and 13 is open. Is the problem found?	-	Go to Step 8	Go to Step 11
7	Turn the ignition switch to LOCK. Check the Oxygen sensor wire between the Oxygen sensor and the ECM connector terminal 44 for a short to ground. Is the problem found?	-	Go to Step 8	Go to Step 11
8	Repair the wire or the connector terminal as needed. Clear the any DTCs from the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
9	Turn the ignition switch to LOCK. Disconnect the Oxygen sensor connector. Turn the ignition switch to ON. Does the scan tool the Oxygen sensor signal voltage between the valve specified?	0.3~0.6V	Go to Step 10	Go to Step 11
10	Replace the Oxygen sensor. Clear the DTCs from the ECM. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
11	Replace the ECM. Perform the diagnostic system check. Is the repair complete?	-	Go to Step 12	-
12	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0132

Front Heated Oxygen Sensor High Voltage

Circuit Description

Conditions for Setting the DTC

The oxygen sensor voltage is more than 1.2V.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.
The coolant fan turns ON.

Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Disconnecting the ECM battery feed for 10 seconds.

Diagnostic Aids

Normal scan tool voltage varies between 0.1volts and 0.9 volts while in closed loop.

Inspect the oxygen (O2) sensor wire. The O2 sensor may be positioned incorrectly and contacting the exhaust manifold.

Check for an intermittent ground in the wire between the O2 sensor and the engine control module.

Perform an injector 2alance test to determine if a restricted fuel injector may be causing the lean condition.

Vacuum of crankcase leaks will cause a lean running condition.

An exhaust manifold gasket leak of a cracked exhaust manifold may cause outside air to be pulled into the exhaust and past the sensor.

DTC P0132 - Front Heated Oxygen Sensor High Voltage

Step	Action	Value(s)	Yes	No
1	Perform an Euro On-Board Diagnostic (EOBD) System Check. Is the system check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Turn the ignition switch to ON, with the engine OFF. Install a scan tool. Engine at operating temperature. Run the engine at 1,200rpm. Does the scan tool the upstream oxygen(O2) sensor1 voltage within the value specified?	More than 1.2V	Go to Step 3	Go to Step 6
3	Turn the ignition switch to LOCK. Disconnect the O2 sensor connector and engine control module (ECM) connector. Check the O2 sensor wire between the O2 sensor and ECM connector terminal 44 for short to battery voltage. Is the problem found?	-	Go to Step 4	Go to Step 5
4	Repair the wire of the connector terminal as needed. Clear the DTCs from the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
5	Turn the ignition switch to LOCK. Replace the O2 sensor. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 7	-
6	Turn the ignition switch to LOCK. Replace the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 7	-
7	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0133

Front Heated Oxygen Sensor No Activity

Circuit Description

Conditions for Setting the DTC

The engine controls system is in closed loop.
Engine Coolant Temperature is higher than 60°C(140°F).
The mass air flow(MAF) is between 60mg/tdc and 160mg/tdc.
The engine speed is between 1,800rpm and 2,900rpm.
The vehicle speed is between 45km/h(28.0mph) and 55km/h(34.2mph).
The manifold air pressure is higher than 700hPa.
The ignition is at 10 volts.
The upstream O2 sensor periods higher than 1.6 seconds.
A number of glitches higher than 5 during the test.
DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0137, P0138, P1671, P0300, P0335, P0336, P0341, P0400, P0404, P0405, P0444, P0445 are NOT SET.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.
The coolant fan turns ON.
The vehicle will operate in Open Loop.

Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Disconnecting the ECM battery feed for 10 seconds.

Diagnostic Aids

Normal scan tool voltage varies between 0.15 to 8.5mV while in Closed Loop. If DTC P0133 is intermittent, refer to "Intermittents" in this section.

DTC P0133 - Front Heated Oxygen Sensor No Activity

Step	Action	Value(s)	Yes	No
1	Perform an Euro On-Board Diagnostic (EOBD) System Check. Is the system check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Connect the scan tool to the data link connector (DLC). Run the engine until it reaches operating temperature. Check for the closed loop operation. Does the scan tool indicate the closed loop?	-	Go to Step 3	Go to Step 4
3	Turn the ignition switch to LOCK. Review the freeze frame data and note the parameters. Operate the vehicle within the freeze frame conditions and Conditions for Setting the DTC. Does the scan tool indicate the closed loop?	-	Go to Step 12	Go to Step 4
4	Disconnect the upstream oxygen(O2) sensor connector. Jumper the oxygen sensor connector terminal B to ground. Turn the ignition switch to ON. Does the scan tool read the oxygen sensor signal voltage the specified valve?	0.4~0.5V	Go to Step 5	Go to Step 8
5	Check the oxygen sensorconnector for malfunction terminals or poor connection and repair as necessary. Is repair necessary?	-	Go to Step 12	Go to Step 6
6	Run the engine at idle. Remove the jumper wire. Measure the voltage between the oxygen sensor connector terminal D and ground. Does the oxygen sensor voltage measure above the specified value?	0.6V	Go to Step 7	Go to Step 11
7	Turn the ignition switch to LOCK. Measure the voltage between the upstream O2 sensor connector terminal D and ground. Does the oxygen sensor voltage measure above the specified value?	0.3V	Go to Step 9	Go to Step 11
8	Repair the wire or the connector between the upstre O2 sensor terminal B and the engine control module (ECM) terminal 44 is open or a short to ground. Is the repair complete?	-	Go to Step 11	Go to Step 9
9	Repair the wire and the connector terminal between the oxygen sensor connector terminal D and the ECM connector terminal 13 is open or a short to ground. Is the repair complete?	-	Go to Step 12	Go to Step 10
10	Turn the ignition switch to LOCK. Replace the ECM. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
11	Replace the O2 sensor. Is the repair complete?	-	Go to Step 12	-
12	Clear any DTCs from the ECM. Perform the diagnostic system check. Is the repair complete.	-	Go to Step 13	-
13	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0135

Front Heated Oxygen Sensor Heater Circuit Not Functioning

Circuit Description

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minmizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the engine control module (ECM). The ECM monitors the current flow through the heater for diagnosis.

If the ECM detects that the HO2S heater current is above or blelow a specified range, DTC P0135 seats.

Conditions for Setting the DTC

DTCs P0106, P0117, P0118, P1017 are not set.
Engine run time is greater than 30 seconds.
Filtered O2 heater current is less than 0.1 amps.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate after three consecutive trip with a fail.
The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
A history Diagnostic Trouble Code (DTC) is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off after three consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm-up cycles without a fault.
DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

An intermittent may be caused by rubbed through wire insulation or a wire contacting the exhaust.

Check for poor connection or damaged harness - inspect harness connectors for the following conditions:

Improper mating
Broken locks
Improperly formed
Damaged terminals
Poor terminal-to-wire connection
Damaged harness

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

The On-Board Diagnostic (EOBD) System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
This step determines if DTC P0135 is the result of a hard failure or an intermittent condition. With the ignition ON, engine OFF, the HO2S1 voltage displayed on the scan tool should change within several minutes toward 0 or 1 volt, indicating that the heater is working properly.
Probing terminal 2 of the HO2S1 connector verifies if voltage is available to the HO2S1 heater.
If voltage is available at the connector, than it becomes a good voltage source to check for a ground at terminal 3.
Determines if voltage is not available at the HO2S1 due to an open in the HO2S1 fuse or open ignition feed circuit. If the fuse is open, determine if it was due to a short in the ignition feed circuit before replacing the fuse.

DTC P0135 - Front Heated Oxygen Sensor Heater Circuit Not Functioning

Step	Action	Value(s)	Yes	No
1	Perform an On-Board Diagnostic (EOBD) System Check. Is the check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Notice : If the engine has just been operating, allow the engine to cool for about one-half hour before proceeding. Turn the ignition switch ON, with the engine OFF. Install a scan tool. Does the Front Heated Oxygen Sensor (HO2S1) voltage gradually change toward the specified voltage?	0 v or 1 v	Go to Step 13	Go to Step 3
3	Disconnect the HO2S1 electrical connector. With a test light connected to ground, probe the ignition feed circuit, terminal A of the connector. Does the test light illuminate?	-	Go to Step 4	Go to Step 5
4	Connect a test light between the ignition feed and ground circuits, terminal A and C of the connector. Does the test light illuminate?	-	Go to Step 6	Go to Step 7
5	Inspect the fuse in the engine fuse block. Is the fuse open?	-	Go to Step 8	Go to Step 9
6	Check the connections terminal A and B at the HO2S2 connector and repair as necessary. Is a repair necessary?	-	Go to Step 13	Go to Step 10
7	Check the connections terminal C at the HO2S1 connector and repair as necessary. Is a repair necessary?	-	Go to Step 13	Go to Step 11
8	Check for a short to ground in the HO2S1 ignition feed circuit and repair as necessary? Replace open fuse. Is the action complete?	-	Go to Step 13	-
9	Check the connections terminal A at the HO2S1 connector and repair as necessary. Is the repair complete?	-	Go to Step 13	Go to Step 12
10	Replace the HO2S1 sensor. Is the action complete?	-	Go to Step 13	-
11	Repair the open in the ground circuit. Is the action complete?	-	Go to Step 13	-
12	Repair the open in the ignition feed circuit. Is the action complete?	-	Go to Step 13	-
13	Using the scan tool, clear the Diagnostic Trouble Codes (DTCs). Start the engine and idle at normal operating temperature. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text. Does the scan tool indicate that this diagnostic has run and passed?	-	Go to Step 14	Go to Step 2
14	Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed?	-	Go to "Applicable DTC table"	System OK

Diagnostic Trouble Code (DTC) P0137

Rear Heated Oxygen Sensor Low Voltage

Circuit Description

Conditions for Setting the DTC

(Case A)

The engine controls system is in closed loop.
Engine speed is less than 6,000rpm.
The heated oxygen sensor voltage is below 0.07V for at least 40 seconds.
DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0335, P0336, P0341, P0342, P0400, P0404, P0405, P0406 are NOT SET.

(Case B)

The engine controls system is in full fuel cut off.
Engine speed is less than 6,000rpm.
The heated oxygen sensor voltage is between 0.352 and 0.499 at least 10 seconds.
DTCs P0107, P0108 and P0141 are NOT SET.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate after three consecutive trip with a fail.
The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.
The coolant fan turns ON.

Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Disconnecting the ECM battery feed for 10 seconds.

Diagnostic Aids

Normal scan tool voltage varies between 0.1 volts and 0.9 volts while in closed loop.
Inspect the oxygen (O2) sensor wire. The O2 sensor may be positioned incorrectly and contacting the exhaust manifold.
Check for an intermittent ground in the wire between the O2 sensor and the engine control module.
Perform an injector 2alance test to determine if a restricted fuel injector may be causing the lean condition.
Vacuum of crankcase leaks will cause a lean running condition.
An exhaust manifold gasket leak of a cracked exhaust manifold may cause outside air to be pulled into the exhaust and past the sensor.

DTC P0137 - Rear Heated Oxygen Sensor Low Voltage

Step	Action	Value(s)	Yes	No
1	Perform an Euro On-Board Diagnostic (EOBD) System Check. Is the system check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Turn the ignition switch to ON, with the engine OFF. Install a scan tool. Engine at operating temperature. Run the engine at 1,200rpm. Does the scan tool the downstream oxygen (O2) sensor1 voltage within the value specified?	0.07-0.52V	Go to Step 4	Go to Step 3
3	Does the scan tool the heated oxygen (O2) sensor1 voltage within the value specified?	0.1V	Go to Step 9	Go to "Diagnostic Aids"
4	Turn the ignition switch to LOCK. Disconnect the Heated O2 sensor connector and engine control module (ECM) connector. Check the Heated O2 sensor wire between the Heated O2 sensor connector terminal 4 and ECM connector terminal 64 for short to ground. Is the problem found?	-	Go to Step 5	Go to Step 6
5	Repair the wire of the connector terminal as needed. Clear the DTCs from the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
6	Turn the ignition switch to LOCK. Disconnect the Heated O2 sensor connector and engine control module (ECM) connector. Check the O2 sensor wire between the O2 sensor connector terminal 1 and ECM connector terminal 14 for short to ground. Is the problem found?	-	Go to Step 7	Go to Step 8
7	Repair the wire of the connector terminal as needed. Clear the DTCs from the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
8	Turn the ignition switch to LOCK. Replace the Heated O2 sensor. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 10	-
9	Turn the ignition switch to LOCK. Replace the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 10	-
10	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0138

Rear Heated Oxygen Sensor High Voltage

Circuit Description

The engine control module (ECM) supplies a voltage of about 450mm volts between the ECM terminals 64 and 13. The Heated oxygen (O2) sensor varies the voltage within a range of about 1volt if the exhaust is rich, down to about 100mm volts if the exhaust is lean. The Heated O2 sensor is like an open circuit and produces no voltage when it is below 360°C(600°F). An open O2 sensor circuit or a cold O2 sensor causes "open loop" operation.

Conditions for Setting the DTC

The Heated oxygen sensor voltage is more than 1.2V.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate after three consecutive trip with a fail.
The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Disconnecting the ECM battery feed for 10 seconds.

Diagnostic Aids

Normal scan tool voltage varies between 0.1volts and 0.9volts while in closed loop.
Inspect the oxygen (O2) sensor wire. The O2 sensor may be positioned incorrectly and contacting the exhaust manifold.
Check for an intermittent ground in the wire between the O2 sensor and the engine control module.
Perform an injector 2alance test to determine if a restricted fuel injector may be causing the lean condition.
Vacuum of crankcase leaks will cause a lean running condition.
An exhaust manifold gasket leak of a cracked exhaust manifold may cause outside air to be pulled into the exhaust and past the sensor.

DTC P0138 - Rear Heated Oxygen Sensor High Voltage

Step	Action	Value(s)	Yes	No
1	Perform an Euro On-Board Diagnostic (EOBD) System Check. Is the system check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Turn the ignition switch to ON, with the engine OFF. Install a scan tool. Engine at operating temperature. Run the engine at 1,200rpm. Does the scan tool the Heated oxygen(O2) sensor voltage within the value specified?	More than 1.2V	Go to Step 3	Go to Step 6
3	Turn the ignition switch to LOCK. Disconnect the Heated O2 sensor connector and engine control module (ECM) connector. Check the Heated O2 sensor wire between the Heated O2 sensor connector terminal 1 and ECM connector terminal 14 for an open or short to battery voltage. Is the problem found?	-	Go to Step 4	Go to Step 5
4	Repair the wire of the connector terminal as needed. Clear the DTCs from the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
5	Turn the ignition switch to LOCK. Replace the Heated O2 sensor. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 7	-
6	Turn the ignition switch to LOCK. Replace the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 7	-
7	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0140

Rear Heated Oxygen Sensor No Activity

Circuit Description

The engine control module (ECM) supplies a voltage of about 450mm volts between the ECM terminals 64 and 13. The oxygen (O2) sensor varies the voltage within a range of about 1volt if the exhaust is rich, down to about 100mm volts if the exhaust is lean. The O2 sensor is like an open circuit and produces no voltage when it is below 360°C(600°F). An open O2 sensor circuit or a cold O2 sensor causes "open loop" operation.

Conditions for Setting the DTC

The engine controls system is in closed loop.
Engine Coolant Temperature is higher than 70°C(158°F).
The engine speed is between 1,300rpm and 3,000rpm.
The vehicle speed is between 26km/h(16.2mph) and 54km/h(33.6mph).
The manifold air pressure is higher than 700hPa.
No transition from rich side to lean side or lean side to rich side during 7.8 seconds even with a forcing of O2 sensor controller.
DTCs P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0137, P0138, P1671, P0300, P0335, P0336, P0341, P0400, P0404, P0405, P0644, P0645 are NOT SET.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.
The coolant fan turns ON.
The vehicle will operate in Open Loop.

Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Disconnecting the ECM battery feed for 10 seconds.

Diagnostic Aids

Normal scan tool voltage varies between 0.15 to 8.5mV while in Closed Loop. If DTC P0140 is intermittent, refer to "Intermittents" in this section.

DTC P0140 - Rear Heated Oxygen Sensor No Activity

Step	Action	Value(s)	Yes	No
1	Perform an Euro On-Board Diagnostic (EOBD) System Check. Is the system check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Run the engine to above the specified operating temperature. Install a scan tool. Operate the engine above the specified rpm for 2minuets. Does the scan tool the indicate Closed Loop?	80°C(176°F) 1,200rpm	Go to Step 3	Go to Step 4
3	Turn the Turn the ignition switch to ON. Review the Freeze Frame data and note the parameters. Operate the vehicle within the freeze frame conditions and Conditions for Setting the DTC as noted? Does the scan tool the indicate Closed Loop?	-	Go to Step 12	Go to Step 4
4	Disconnect the Heated O2 sensor connector and jumper the Heated O2 sensor low circuit, terminal 4 to ground. Is the HO2 voltage below the specified value and does the scan tool indicate the heated oxygen sensor heater voltage within the specified value?	0.5V	Go to Step 5	Go to Step 6
5	Check the Heated O2 sensor connector for malfunction terminals or poor connection and repair as necessary. Is repair necessary?	-	Go to Step 12	Go to Step 9
6	Turn the ignition switch to On. Remove the jumper wire. Using a digital voltmeter(DVM), measure the voltage between the Heated O2 sensor signal circuit, terminal 1 to ground. Does the Heated O2 sensor voltage measure above the specified value?	0.6V	Go to Step 10	Go to Step 9
7	Does the Heated O2 sensor voltage measure below the specified value?	0.3V	Go to Step 11	Go to Step 8
8	Check the Heated O2 sensor ground circuit, terminal 4 for an open or poor connection and repair as necessary. Is repair necessary?	-	Go to Step 12	Go to Step 8
9	Check the Heated O2 sensor signal circuit, terminal 1 for an open or poor connection and repair as necessary. Is repair necessary?	-	Go to Step 12	Go to Step 8
10	If disconnected, reconnect Heated O2 sensor connector. Using the scan tool, clear the DTCs. Start the engine and idle at normal operating temperature. Operate the vehicle within the conditions for setting this DTC as specified in the supporting text. Does the scan tool indicated that this diagnostic has run and passed?	-	Go to Step 13	Go to Step 2
11	Turn the ignition switch to LOCK. Replace the Heated O2 sensor. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 15	-
12	Turn the ignition switch to LOCK. Replace the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 15	-
13	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0141

Rear Heated Oxygen Sensor Heater Malfunction

Circuit Description

Conditions for Setting the DTC

The heated O2 sensor heater resistance is less than 10Ω or greater than 30Ω.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate after three consecutive trip with a fail.
The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.
The coolant fan turns ON.

Conditions for Clearing the MIL/DTC

The MIL will turn off after four consecutive ignition cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 consecutive warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.
Disconnecting the ECM battery feed for 10 seconds.

Diagnostic Aids

Normal scan tool voltage varies between 0.1volts and 0.9 volts while in closed loop.
Inspect the oxygen (O2) sensor wire. The O2 sensor may be positioned incorrectly and contacting the exhaust manifold.
Check for an intermittent ground in the wire between the O2 sensor and the engine control module.
Perform an injector 2alance test to determine if a restricted fuel injector may be causing the lean condition.
Vacuum of crankcase leaks will cause a lean running condition.
An exhaust manifold gasket leak of a cracked exhaust manifold may cause outside air to be pulled into the exhaust and past the sensor.

DTC P0141 - Rear Heated Oxygen Sensor Heater Malfunction

Step	Action	Value(s)	Yes	No
1	Perform an Euro On-Board Diagnostic (EOBD) System Check. Is the system check complete?	-	Go to Step 2	Go to "On-Board Diagnostic System Check"
2	Turn the ignition switch to LOCK. Disconnect the Heated O2 sensor connector and engine control module (ECM) connector. Check the Heated O2 sensor heater wire between the Heated O2 sensor connector terminal 4 and ECM connector terminal 64 for an open or short to ground. Is the problem found?	-	Go to Step 3	Go to Step 4
3	Repair the wire of the connector terminal as needed. Clear the DTCs from the ECM. Road tests the vehicle. Perform the diagnostic system check. Is the repair complete?	-	System OK	-
4	Turn the ignition switch to LOCK. Replace the Heated O2 sensor. Road tests the vehicle. Perform the diagnostic system check. Is the replacement complete?	-	Go to Step 6	-
5	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK