Refer to Engine Control Schematics
Heated Oxygen Sensors
.
Circuit Description
The oxygen sensor heater is a device used to reduce the time that the sensor takes to go active. The bank 1 sensor 2 heater helps to maintain the sensor at the proper temperature for catalyst testing, and additional adjustments to FT . The bank 1 sensor 2 heater receives power through a fused ignition circuit. The PCM turns the heater ON, and OFF using a low side driver (ODM) located within the PCM. The PCM monitors the low side driver for circuit conditions that are incorrect for the commanded state of the low side driver. If the PCM detects an incorrect circuit condition, DTC P0036 will set.
Conditions for Running the DTC
System voltage is between 9-18 volts.
Conditions for Setting the DTC
The PCM detects an incorrect circuit condition for the commanded state of the low side driver.
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using the scan tool Clear DTC information function. |
Diagnostic Aids
If the condition is intermittent, refer to Intermittent Conditions in Symptoms.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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If the DTC sets with the ignition ON, this indicates the bank 1 sensor 2 heater low circuit is shorted to ground or open. If the HO2S fuse is open, the starter will not engage. Ensure you test all related circuits for a short to ground.
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If the DTC sets with the engine operating, this indicates the bank 1 sensor 2 heater low circuit is shorted to a voltage.
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An open HO2S fuse causes multiple DTCs to set. If the fuse is open, the starter will not engage. Ensure you test all related circuits for a short to ground.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |
Does DTC P0036 set? | -- | Go to Step 4 | Go to Step 3 | |
Important: If the engine does not crank, go to step 4. Does DTC P0036 set? | -- | Go to Step 9 | Go to Intermittent Conditions | |
4 | Is OXY SEN 2 fuse open? | -- | Go to Step 5 | Go to Step 6 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 | |
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 13 |
7 | With a DMM, measure the voltage at the HO2S bank 1 sensor 2 heater low circuit. Is the voltage near the specified voltage? | 2V | Go to Step 11 | Go to Step 8 |
8 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 12 |
9 |
Is the voltage near the specified value? | 2V | Go to Step 14 | Go to Step 10 |
10 | Test the HO2S bank 1 sensor 2 heater low circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 |
11 | Inspect for poor connections at the harness connector of the HO2S bank 1 sensor 2. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 |
12 | Inspect for poor connections at the harness connector of the PCM . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 |
13 | Repair the open HO2S bank 1 sensor 2 supply voltage circuit. Did you complete the repair? | -- | Go to Step 16 | -- |
14 | Replace HO2S bank 1 sensor 2. Refer to Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 . Did you complete the replacement? | -- | Go to Step 16 | -- |
15 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Step 16 | -- |
16 |
Does the scan tool display the DTC ran and passed? | -- | System OK | Go to Step 2 |
