P1134

Schematic:

The Oxygen Sensor 1 (O2S-1) is an electrical source that responds to oxygen content in the exhaust manifold. When the sensor reaches approximately 316°C (600°F), it produces a voltage based on the difference in oxygen between the atmosphere and exhaust gas. The PCM sends a bias voltage (391-491 mV) on the signal line which is pulled up through high resistance. When the O2S-1 is cold, it produces no voltage and has extremely high internal resistance. The internal resistance of the sensor is much greater than the resistance of the bias pull-up resistor. However, when the sensor heats up, it produces voltage that overrides the bias voltage. This voltage is read by the PCM to determine a rich/lean O2S-1 signal used to adjust injector pulse width. Under normal conditions, low sensor voltage means high oxygen content/lean air-fuel mixture and vice versa. Normal sensor readings will fluctuate between 10 mV and 999 mV DTC P1134 sets when the O2S-1 signal rich to lean and lean to rich average response time ratio is too high or too low.

DTC PARAMETERS
DTC P1134 will set if the ratio of the O2S-1 lean to rich avg. time to the rich to lean avg. time is not within 0.6 to 2.8 within a 100 second test when:
^ Engine speed is between 1500 and 3000 RPM
^ Loop status is closed
^ Calculated air flow is greater than 7 gm/s
^ Commanded air/fuel ratio is 14.7 to 1
^ No cam, CKP, ECT, EGR, EVAP purge solenoid, fuel trim, IAT, MAP misfire, O2S-1, system voltage or TP sensor DTCs have been set.

DTC P1134 diagnostic runs once per ignition cycle once the above conditions have been met.

DTC P1134 is a type B DTC.

DIAGNOSTIC AIDS
Possible causes of DTC P1134:
^ An intermittent connection or corrosion in the O2S-1 harness connector can set this DTC. Use Scan tool to monitor O2S-1 voltage with engine running at normal operating temperature while wiggling the signal and ground (circuit 413) wire. Make sure the sensor is tight.
^ The most probable cause for DTC P1134 is contamination. Check for obvious contamination (oil, fuel or engine coolant) by removing sensor. Identify and correct the cause of the contamination if contaminated. Replace the O2S-1.