P1134

Diagnostic Chart:

Wiring 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

^ No active misfire, Crankshaft Position (CKP) sensor, injector circuit, Mass Air Flow (MAF) sensor, Throttle Position (TP) sensor, EVAP, Intake Air Temperature (IAT) sensor, Manifold Absolute Pressure (MAP) sensor, fuel trim, EGR, Engine Coolant Temperature (ECT) sensor or HO2S heater DTC(s).

^ Above conditions present for a 100 second monitoring period after closed loop.

^ HO2S 1 transition time ratio is less than 0.4 or greater than 5.0.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM will illuminate the Malfunction Indicator Lamp (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 Clear Info 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 Front Heated Oxygen Sensor (HO2S 1).

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

TEST DESCRIPTION

The number below refers to the step number on the Diagnostic Table:

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

7. Before replacing the HO2S, check for silicon contamination.