P1153

Circuit Description

The PCM monitors the Heated Oxygen Sensor (HO2S) activity. The PCM counts the number of times that the HO2S signal voltage crosses the rich to lean and lean to rich thresholds for a 100 second test period. If the PCM determines that the HO2S did not switch enough times, DTC P1153 will be set. A lean to rich switch is determined when the HO2S voltage changes from less than 300 mV to greater than 600 mV. A rich to lean switch is determined when the HO2S voltage changes from more than 600 mV to less than 300 mV.

Conditions for Running the DTC

^ No Fuel Injector, MAF, TP, EVAP, IAT, MAP, Fuel Trim, EGR or ECT DTCs are set.
^ DTC P0135 is not set.

Conditions for Setting the DTC

^ The PCM monitors fewer than 40 lean to rich and rich to lean switches for Bank 2 HO2S 1.
^ The HO2S voltage remains between 300 and 600 millivolts.
^ The conditions are present for a 2 minute after closed loop enable.

Action Taken When the DTC Sets

^ The PCM will illuminate the MIL during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Fail Records data.

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.

Diagnostic Aids

A malfunction in the HO2S heater ignition feed or ground circuit may cause a DTC P1153 to set. Check HO2S heater circuitry for intermittent faults or poor connections. If connections and wiring are OK and DTC P1153 continues to set, replace the Bank 2 HO2S 1. Review the Fail Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

Test Description

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

2. This step determines if the fault is present. This test may take 5 minutes for the diagnostic to run.
3. A condition that affects other heated oxygen sensors indicates probable contamination. To avoid damaging replacement sensors, correct the condition which caused the contamination before replacing the affected sensors.
4. A exhaust leak 6 to 12 inches away from the HO2S can cause this DTC to set.
5. This step checks for conditions which may cause the heated oxygen sensor to appear faulty. Correct any of the described conditions if present.
6. This step checks for a short to ground in the signal circuit to the PCM. If the signal circuit is shorted to ground the scan tool will display less than 200 mV.
7. This step checks for a short to ground in the low circuit to the PCM. If the low circuit is shorted to ground the scan tool will display less than 200 mV.
8. This step checks the integrity of both the signal and low circuits to the PCM. If the circuits are functioning properly the scan tool will display less than 200 mV.
9. To avoid damaging replacement sensors, correct the condition which caused the contamination before replacing the affected sensors.