P0134
DTC P0134 O2 Bank 1 Sensor 1 No Activity
Circuit Description
The engine control module (ECM) supplies a voltage of about 0.45 volts between terminals C14 and 015 (if measured with a 10 megohm digital voltmeter, this may read as low as 0.32 volts). The Oxygen Sensor (O2S 1) varies the voltage within a range of about 1 volt if the exhaust is rich, down through about 0.10 volts if the exhaust is lean.
The sensor is like an open circuit and produces no voltage when it is below 315 °C (600 °F). An open sensor circuit or cold sensor causes Open Loop operation.
If the O2S 1 pigtail wiring, connector, or terminal is damaged, the entire O2S 1 assembly must be replaced. Do not attempt to repair the wiring, connector, or terminals. In order for the sensor to function properly, it must have a clean air reference provided to it. This clean air reference is obtained by way of the O2S 1 wire(s). Any attempt to repair the wires, connector, or terminals could result in the obstruction of the air reference and degrade the O2S 1 performance. Refer to Oxygen Sensor".
Conditions for Setting the DTC
- O2S 1 voltage is between 374 mv and 522 mv.
- Engine run time is greater than 60 seconds.
- No related malfunctions.
- Oxygen sensor not heated.
Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.
- The coolant fan turns on.
- The vehicle will operate in Open Loop.
Conditions for Clearing the MIL/DTC
- The MIL will turn off after three consecutive ignition cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm-up cycles without a fault.
- The DTC(s) can be cleared by using the scan tool.
Diagnostic Aids
Normal scan tool voltage varies between 150 mv to 850 mv (0.15 volts to 0.85 volts) while in Closed Loop If DTC P0134 is intermittent, refer to "Intermittents".
Steps 1 - 10:
Steps 11 - 13:
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
2. During engine warm-up, the O2S 1 should warm up, and its voltage output should vary between 150 mv and 850 mv. When the O2S 1 voltage varies, the engine will go into Closed Loop. This determines if the O2S 1 is operating properly.
4. This will determine if the sensor is malfunctioning or the wiring or ECM is the cause of the DTC P0134.
6. Use only a high impedance digital voltmeter (DVM) for this test. The test checks the continuity of the O2S 1 signal and the ground circuits; if the ground circuit is open, the ECM voltage on the circuit will be over 0.6 volts (600 mv).