Circuit Description
The PCM supplies a voltage of about 450 mV between the HO2S high and low signal circuits. The oxygen sensor varies the voltage over a range from about 1000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.
The PCM monitors and stores the heated oxygen sensor (HO2S) voltage information. The PCM evaluates the HO2S voltage samples in order to determine the amount of time the HO2S voltage was out of range. The PCM compares the stored HO2S voltage samples taken within each sample period and determines if majority of the samples are out of the operating range.
The PCM monitors the HO2S voltage and detects if the voltage goes out of the bias range. If the PCM does not detect the voltage went out of the bias range, this DTC will set.
Conditions for Setting the DTC
| • | DTCs P0102, P0103, P0112, P0113, P0117, P0118, P0335, P0336, P1120, P1220, P1221, not set. |
| • | The ignition voltage is greater than 9.0 volts. |
| • | The fuel system is operating in Closed Loop. |
| • | The engine run time is greater than 70 seconds. |
| • | The engine coolant temperature is greater than 60°C (140°F). |
| • | The HO2S signal voltage is steady between 350 mV and 550 mV. |
| • | The conditions present for 60 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminate the malfunction indicator lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails, if the diagnostic fails under the same conditions (load, RPM, temperature, etc.) as the previous ignition cycle that the test ran and failed. |
| • | The first time the diagnostic fails, the PCM records the operating conditions in Failure Records. |
| • | The second consecutive drive trip that this diagnostic fails under the same conditions (load, RPM, temperature, etc.) as the previous ignition cycle that the test ran and failed, the PCM stores this information in Freeze Frame. The PCM copies any data previously stored in Freeze Frame and copies the data into the Failure Records. The PCM then overwrites the Freeze Frame and the PCM updates the HO2S data in the Failure Records. |
| • | Open Loop Fueling. |
Conditions for Clearing the MIL/DTC
| Important: If the last failure was during a non-typical driving condition, the MIL may remain ON longer than the three drive trips. Review the Freeze Frame and Failure Records for the last failure conditions. |
| • | The PCM turns the MIL OFF after 3 consecutive drive trips that the diagnostic runs and does not fail within the same conditions that the DTC last failed. |
| • | A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| • | A last test failed (Current DTC) clears when the diagnostic runs and does not fail. |
| • | The PCM battery voltage is interrupted. |
| • | Use a scan tool in order to clear the MIL/DTC. |
Diagnostic Aids
Important: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
| • | An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provides the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination. Refer to Body and Accessories/Wiring Systems. |
| • | Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Symptoms . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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The engine must be at the normal operating temperature before performing this test. For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616 . Using this kit prevents damage to the harness connector terminals.
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Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you can not duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate the vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that the PCM recorded. This will isolate when the DTC failed. Refer to Symptoms .
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If the scan tool indicates the HO2S voltage goes below 200 mV, this indicates the HO2S circuits and PCM are OK.
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This step checks whether the signal circuit from the PCM is OK.
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Disconnecting the PCM allows using a DMM J 39200 in order to check continuity of the circuits. This aids in locating an open or shorted circuit.
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Disconnecting the PCM allows using a DMM J 39200 in order to check continuity of the circuits. This aids in locating an open or shorted circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
|
Important: Check the HO2S for being secure before proceeding with this DTC. A sensor that is loose could cause this DTC to set.
Does the scan tool indicate the Bank 1 HO2S 1 voltage varying outside the specified range? | 350-550 mV | |||
Does the scan tool indicate that this diagnostic failed this ignition? | -- | Go to Diagnostic Aids | ||
Is the Bank 1 HO2S 1 voltage below the specified value? | 200 mV | |||
Does the Bank 1 HO2S 1 voltage measure above the specified value? | 375 mV | |||
Did you find and correct the Bank 1 HO2S 1 low circuit condition? | -- | |||
Did you find and correct the Bank 1 HO2S 1 low circuit condition? | -- | |||
8 | Check for a poor Bank 1 HO2S 1 signal or low circuit terminal connection at the Bank 1 HO2S 1 harness connector and replace the terminal(s) if necessary. Refer to Body and Accessories/Wiring Systems. Did any terminals require replacement? | -- | ||
9 | Check for a poor Bank 1 HO2S 1 low circuit terminal connection at the PCM, and replace the terminal if necessary. Refer to Body and Accessories/Wiring Systems. Did the terminal require replacement? | -- | ||
10 | Check for a poor Bank 1 HO2S 1 signal circuit terminal connection at the PCM and replace terminal if necessary. Refer to Body and Accessories/Wiring Systems. Did the terminal require replacement? | -- | ||
11 | Replace the Bank 1 HO2S 1. Refer to Heated Oxygen Sensor Replacement - Bank 1 . Is the action complete? | -- | -- | |
12 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module Replacement . Replace the PCM. Is the action complete? | -- | -- | |
13 |
Does the scan tool indicate that this test ran and passed? | -- | ||
14 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
