P0133 or P0153 (W/Case Grounded HO2S)
CIRCUIT DESCRIPTIONThis diagnostic applies only to vehicles built with case grounded heated oxygen sensors (HO2S). To identify the HO2S, refer to Computers and Controls Systems Component Views.
The powertrain control module (PCM) continuously monitors the HO2S activity for 100 seconds. During the monitor period, the PCM counts the number of times that the HO2S responds from rich-to-lean and from lean-to-rich and adds the amount of time necessary to complete all transitions. With this information, the PCM can determine the average time for all transitions. If the average response time is too slow, a diagnostic trouble code (DTC) sets.
The PCM determines the lean to rich transition when the HO2S voltage changes from less than 300 mV to more than 600 mV. The PCM determines the rich to lean transition when the HO2S voltage changes from more than 600 mV to less than 300 mV.
CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0117, P0116, P0118, P0121, P0122, P0123, P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0200, P0300, P0401, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P1120, P1125, P1220, P1221, P1258, P1404,, P1441, P1514, P1515, P1516, P1517, or P1518 are not set.
^ The engine coolant temperature (ECT) is more than 65°C (149°F).
^ The engine run time is more than 160 seconds.
^ The evaporative emission (EVAP) purge solenoid command is more than 1 percent.
^ The mass air flow (MAF) is between 23-50 g/s.
^ The engine speed is between 1,200-3,000 RPM.
^ For vehicles without throttle-actuated control (TAC), the throttle position (TP) is more than 5 percent.
^ For vehicles with TAC, the TP indicated angle is 5 percent more than the value observed at idle.
^ The vehicle is operating in Closed Loop.
^ The ignition 1 signal is between 9-18 volts.
^ The fuel tank level remaining is more than 10 percent.
^ Intrusive tests are not in progress.
^ The scan tool output controls are not active.
^ The above conditions are met for 100 seconds.
CONDITIONS FOR SETTING THE DTC
The rich-to-lean and lean-to-rich response time average is more than a calibrated value.
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.
DIAGNOSTIC AIDS
IMPORTANT: Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
^ This diagnostic only runs once per ignition cycle.
^ A malfunction in the HO2S heater circuits causes a DTC to set. Inspect the HO2S heater circuits for intermittent opens and faulty connections. Refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.
^ An oxygen supply inside the HO2S is necessary for proper operation. The HO2S wires provide the supply of oxygen. Inspect the HO2S wires and connections for breaks or contamination. Refer to Heated Oxygen Sensor (HO2S) Wiring Repairs in Diagnostic Aids.
^ Using the Freeze Frame/Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass or a fail. Operate the vehicle within the same Freeze Frame conditions such as RPM, load, vehicle speed, temperature, etc. that you observed. This will isolate when the DTC failed. For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions
TEST DESCRIPTION
Steps 1-6:
Steps 7-15:
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the fault is present. This test may take 5 minutes for the diagnostic to run.
3. When DTCs P0133 and P0153 are set at the same time, it is a good indication that a fuel contamination problem is present.
4. An exhaust leak 15.2-30.4 cm (6-12 inches) away from the HO2S can cause a DTC to set.
5. This step tests whether a good ground circuit is available.
6. This step tests the integrity of the low signal circuit to the PCM.
7. This step tests the integrity of the low signal circuit to the PCM.
8. Certain RTV silicone gasket materials emit vapors that can contaminate the HO2S. There is also a possibility of silicone-contamination caused by silicone in the fuel. If the sensors appear to be contaminated by silicone and all the silicone sealant is a non silicone base, advise the customer to try a different fuel company. A missing fuel filler restrictor indicates the customer may have used leaded fuel.