P0030

DTC P0030

CIRCUIT DESCRIPTION
The heated oxygen sensor (HO2S) heater reduces the time required for the oxygen sensor to reach operating temperature and maintains the operating temperature during extended idle periods. When the ignition is turned to the ON position, ignition voltage is supplied directly to the sensor heater. The PCM controls the heater by grounding the control circuit with a solid state device called a driver. If the PCM detects the control circuit voltage is not within a predetermined range when the circuit is commanded ON or OFF, this DTC sets.

DTC DESCRIPTORS
This diagnostic procedure supports the following DTCs.
- DTC P0030 Heater Control Circuit Bank 1 Sensor 1
- DTC P0036 Heater Control Circuit Bank 1 Sensor 2
- DTC P0050 Heater Control Circuit Bank 2 Sensor 1
- DTC P0056 Heater Control Circuit Bank 2 Sensor 2

CONDITIONS FOR RUNNING THE DTC
- Conditions for running DTCs P0030 and P0050
- The engine is operating.
- DTCs P0133, P0153, P2238, P2241, P2242, P2243, P2245, P2247, P2249, P2252, P2255, P2256, P2297, P2298, P2414, P2415, P2627, P2628, P2630, and P2631 are not set.
- The heater control circuit is being commanded ON and OFF.
- Conditions for running DTCs P0036 and P0056
- The ignition is ON.
- The heater control circuit is being commanded ON and OFF.
- DTCs P0030, P0036, P0050, and P0056 run continuously once the above conditions are met for more than 1 second.

CONDITIONS FOR SETTING THE DTC
- The PCM detects the heater control circuit voltage is less than a predetermined range when the circuit is commanded OFF.
- The PCM detects the heater control circuit voltage is more than a predetermined range when the circuit is commanded ON.
- The condition exists for more than 1 second.

ACTION TAKEN WHEN THE DTC SETS
- The powertrain control module (PCM) illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
- The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame/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
- An open fuse in the HO2S heater circuit may be caused by the heater element in one of the sensors. The condition may not be present until the sensor operates for a period of time. If no fault is present in the heater circuit, monitor the amperage of each heater using the DMM to determine if one of the heater elements is the cause of the open fuse.
- Inspect the sensor pigtail or the harness for contacting the exhaust system.
- For an intermittent condition, refer to Intermittent Conditions. Intermittent Conditions

TEST DESCRIPTION

Steps 1-9:

Steps 10-16:

The numbers below refer to the step numbers on the diagnostic table.
4. If all DTCs are set for either the front sensors or the rear sensors, the ignition voltage circuit to the heaters may be open. The front sensors and rear sensors share the same fuse.