P0135
DTC P0135
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, through 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 the PCM can predict the sensor temperature. 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0135 HO2S Heater Performance Sensor 1
Conditions for Running the DTC
Heater Current Test
* DTCs P0030 is not set.
* The Ignition 1 Signal parameter is between 11-18 volts.
* The Mass Airflow (MAF) Sensor parameter is between 5-25 g/s.
* The Engine Run Time parameter is more than 60 seconds.
* The Engine Speed parameter is between 500-3,000 RPM.
* The Ignition 1 Signal parameter varies less than 1 volt.
* DTC P0135 runs the heater current test twice per drive cycle when the above conditions are met for 2 seconds.
Heater Resistance Test
* DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0117, P0118, P0120, P0121, P0201, P0202, P0203, P0204, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P1516, P2101, P2135, P2176 are not set.
* The ignition is OFF for more than 10 hours.
* The ECT Sensor parameter is between -30°C and +45°C (-22°F and +113°F) at engine start-up.
* The ECT Sensor parameter minus the Intake Air Temperature (IAT) Sensor parameter is less than 140°C (252°F) at engine start-up.
* The engine is started.
* DTC P0135 runs the heater resistance test once per drive cycle when the above conditions are met.
Conditions for Setting the DTC
Heater Current Test
* The PCM detects that the HO2S 1 Heater Current parameter is more than 1.7 amps or less than 0.301 amps.
* DTC P0135 sets during the heater current test within 60 seconds when the above condition is met.
Heater Resistance Test
* The PCM detects that the HO2S 1 heater calculated resistance is not within the expected range at engine start-up.
* DTC P0135 sets during the heater resistance test 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
