P0141
DTC P0135 or P0141
Circuit Description
Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The 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, though a low side driver within the powertrain control module (PCM).
The PCM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The PCM determines the temperature by measuring the current flow through the heater and calculating the resistance. Based on the resistance of the PCM can predict the sensor temperature. HO2S 1 uses pulse width modulation (PWM) to control the heater operation. HO2S 2 simply uses ON/OFF commands to control the heater operation. For diagnosis, the PCM monitors the heater current with the engine running. The PCM also calculates the heater resistance on a cold start. Both diagnostics will only run once per ignition cycle. If the PCM detects that the heater current or the heater calculated resistance is not within an expected range, DTC P0135 sets for HO2S 1 or DTC P0141 sets for HO2S 2.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
* DTC P0135 HO2S Heater Performance Sensor 1
* DTC P0141 HO2S Heater Performance Sensor 2
Conditions for Running the DTC
* DTCs P0068, P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0120, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0205, P0206, P0220, P0300-P0306, P0315, P0336, P0442, P0446, P0452, P0453, P0455, P0483, P0496, P0506, P0507, P0601, P0602, P0604, P0606, P060D, P060E, P0641, P0651, P1516, P1621, P2101, P2120, P2125, P2135, P2138, P2176 are not set.
* The ECT sensor parameter is more than 70°C (158°F).
* The Ignition 1 Signal parameter is between 10-17 volts.
* The Air Flow Calculated parameter is less than 50 g/s.
* The Fuel Level Sensor parameter is more than 10 percent.
* The Engine Run Time parameter is more than 60 seconds.
* DTCs P0135 or P0141 run continuously during the heater current test when the above conditions are met.
Conditions for Setting the DTC
* For DTC P0135, the PCM detects that the HO2S 1 Heater Current parameter is more than 2.99 amps or less than 0.80 amps.
* For DTC P0141, the PCM detects that the HO2S 2 Heater Current parameter is more than 1.56 amps or less than 0.217 amps.
* DTCs P0135 or P0141 set within 200 seconds during the heater current test 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
