P1134

Diagnostic Chart:

Diagnostic Chart (cont'd):

Electrical Diagram:

CIRCUIT DESCRIPTION

The PCM continuously monitors the Heated Oxygen Sensor (HO2S) activity for 100 seconds. During the monitor period the PCM counts the number of times that the HO2S responds from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions. With this information, an average time for all transitions can be determined. The PCM then divides the rich to lean average by the lean to rich average to obtain a ratio. If the HO2S transition time ratio is not within range, DTC P1134 will be set, indicating that the oxygen sensor is not responding as expected to changes in exhaust oxygen content.


CONDITIONS FOR SETTING THE DTC

1. No injector, MAF sensor, Throttle Position (TP) sensor, EVAP, IAT sensor, MAP sensor, Fuel Trim, EGR, ECT sensor DTCs set.

2. DTC P0135 (02 Heater) not set.

3. The engine has been running at least 2 minutes.

4. Engine speed is between 1000 RPM and 3000 RPM.

5. Mass Air Flow is between 15 gm/s and 30 gm/s.

6. Engine Temperature is greater than 75°C (167°F).

7. Above conditions present for a 100 second monitoring period.

8. Bank 1 HO2S 1 transition time ratio is less than 0.4 or greater than 3.5.


ACTION TAKEN WHEN THE DTC SETS

- The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second key cycle in which the DTC sets.

- Open Loop fuel control will be in effect.

- 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 on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.

- A history DTC P1134 will clear after 40 consecutive warm-up cycles have occurred without a fault.

- DTC P1134 can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.


DIAGNOSTIC AIDS

A malfunction in the HO2S heater ignition feed or ground circuit may cause a DTC P1134 to set. Check HO2S heater circuitry for intermittent faults or poor connections. If connections and wiring are OK and DTC P1134 continues to set, replace the bank 1 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:

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.

5. This step checks for conditions which may cause the heated oxygen sensor to appear faulty. Correct any of the described conditions if present.

8. To avoid damaging replacement sensors, correct the condition which caused the contamination before replacing the affected sensors.