P0135
DTC P0135
CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the engine control module (ECM). The ECM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The ECM monitors the current flow through the heater for diagnosis. If the ECM detects that the current is above or below a specified range, DTCs P0135 sets.
DTC DESCRIPTORS
This diagnostic procedure supports the following DTC:
DTC P0135 HO2S Heater Performance Sensor 1
CONDITIONS FOR RUNNING THE DTC
- The Ignition 1 parameter is more than 10.9 volts.
- The engine is running.
- The affected HO2S Heater Command parameter is ON.
- DTC P0135 runs twice per drive cycle when the above conditions are met.
CONDITIONS FOR SETTING THE DTC
- The ECM detects that the affected HO2S Heater Current parameter is more than 1.502 amps or less than 0.249 amps.
- DTC P0135 sets within 5 seconds when the above condition is met.
ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.
TEST
