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P0154



DTC P0154

DTC DESCRIPTOR

DTC P0151
HO2S Circuit Low Voltage Bank 2 Sensor 1

DTC P0152
HO2S Circuit High Voltage Bank 2 Sensor 1

DTC P0154
HO2S Circuit Insufficient Activity Bank 2 Sensor 1

DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection






TYPICAL SCAN TOOL DATA






CIRCUIT/SYSTEM 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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The control module supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the control module operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust stream.

CONDITIONS FOR RUNNING THE DTC

DTC P0151
- DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0201, P0202, P0203, P0203, P0204, P0205, P0206, P0220, P0442, P0443, P0446, P0449, P0452, P0453, P0454, P0455, P0464, P0496 are not set.
- DTCs P0430 and P2A03 are not commanding fuel.
- The system voltage is between 9-18 volts.
- The scan tool special functions are not active.
- The Air Fuel Ratio parameter is between 12:1-16.5:1.
- The throttle position (TP) sensor parameter is between 4-40 percent.
- When not in the power enrichment (PE) mode, the following conditions must also be met:
- The Air Fuel Ratio parameter is between 12:1-16.5:1.
- The TP sensor parameter is between 4-40 percent.
- The Loop Status parameter is closed.
- The engine coolant temperature (ECT) parameter is less than 131°C (267°F).
- All fuel injectors are ON.
- The traction control is not active.
- During PE mode, the following conditions must also be met:
- The Engine Run Time parameter is more than 5 minutes.
- The Air Fuel Ratio parameter is more than 16.5:1.
- The above conditions are present for at least 2 seconds.

DTC P0152
- DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0220, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0455, P0464, P0496, P2153 are not set.
- DTC P0420 and P2A04 are not commanding fuel.
- The system voltage is between 9-18 volts.
- The scan tool special functions are not active.
- The TP sensor parameter is between 3-40 percent.
- The Air Fuel Ratio parameter is between 12:1-16.5:1.
- The above conditions must be met for at least 3 seconds.

DTC P0154
- DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0220, P0442, P0443, P0446, P0449, P0451, P0452, P0453, P0454, P0455, P0464, P0496, P2135 are not set.
- DTCs P0420 and P2A04 are not commanding fuel.
- The system voltage is between 9-18 volts.
- The scan tool special functions are not active.
- The HO2S 1 Heater parameter is ON.
- The Engine Run Time parameter is more than 2 minutes.

CONDITIONS FOR SETTING THE DTC

DTC P0151
- The engine control module (ECM) detects that the HO2S 1 signal voltage is less than 78 mV for more than 51 seconds. OR
- The ECM detects that the HO2S 1 signal voltage is less than 598 mV during PE mode for more than 7.5 seconds.
- This diagnostic runs continuously.

DTC P0152
- The ECM detects that the HO2S 1 signal voltage is more than 889 mV for more than 75 seconds.
- This diagnostic runs continuously.

DTC P0154
- The ECM detects that the HO2S 1 signal voltage is between 382-525 mV for more than 30 seconds.
- This diagnostic runs continuously.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION
- Allow the engine to reach operating temperature. With the engine running, observe the affected HO2S parameter with a scan tool.
- The HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes.
- The HO2S 2 value should change more than 200 mV when the throttle is quickly cycled three times from Closed to Wide Open and back to Closed after running the engine at 1500 RPM for 30 seconds.
- If any HO2S heater DTCs are set, diagnose those DTCs first.
- The affected HO2S may be damaged due to contamination. Prior to replacing the affected HO2S, inspect for the following sources of contamination:
- A silicon contaminated HO2S

NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice.

- Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis. Alcohol/Contaminants-in-Fuel Diagnosis
- Engine oil consumption-Refer to Oil Consumption Diagnosis. Component Tests and General Diagnostics
- Engine coolant consumption-Refer to Loss of Coolant. Loss of Coolant

CIRCUIT/SYSTEM TESTING
1. With the engine running at operating temperature, observe the affected HO2S sensor parameter with a scan tool and manipulate the related wiring and connectors. Manipulation should not affect the parameter.
- If manipulation does affect the parameter, repair the harness or connector.
2. With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 4 mV from the affected HO2S sensor low signal circuit to ground.
- If more than approximately 4 mV, test the affected HO2S sensor low signal circuit for a short to voltage or a faulty control module.
- If less than approximately 4 mV, test the affected HO2S sensor low signal circuit for high resistance or for a faulty control module.
3. With the ignition ON, the engine OFF, and the sensor disconnected, measure for approximately 412 mV from the affected HO2S sensor high signal circuit to ground.
- If more than approximately 412 mV, test the affected HO2S sensor high signal circuit for a short to voltage or a faulty control module.
- If less than approximately 412 mV, test the affected HO2S sensor high signal circuit for a short to ground, high resistance, or for a faulty control module.
4. With the ignition ON, the engine OFF, and the sensor disconnected, install a 3-amp fused jumper between the affected HO2S sensor high signal circuit and the affected HO2S sensor low signal circuit. The affected HO2S parameter should indicate 0 mV.
- If all circuits and connectors test normal and the affected HO2S parameter does not indicate 0 mV, replace the control module.
5. With the ignition ON, the engine OFF, and the sensor disconnected, install a test lamp between the affected HO2S sensor high signal circuit and battery voltage. The affected HO2S parameter should indicate approximately 1106 mV.
- If all circuits and connectors test normal and the affected HO2S parameter does not indicate 1106 mV, replace the control module.
6. If the control module and all circuits test normal, replace the affected HO2S sensor.

REPAIR INSTRUCTIONS

NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice.

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 1
- Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2
- Control Module References Verification Tests

REPAIR VERIFICATION
1. Clear the DTCs with a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
- If this DTC resets, repeat this procedure.
- If this DTC does not reset but others do, perform those diagnostics.
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