PDU - Software Error

PDU-4

PDU 1001 Software - Error - Does Not
Recognize V12 6.0L DTC 67

MODEL: XJ12 and XJS V12

DATE: 7/94

ISSUE:

If DTC 67 (Air injection operation) is flagged on the Vehicle Condition Monitor, PDU will not recognize or erase the code.

ACTION:

If DTC 67 is indicated on the VCM of YJS V12 or XJ12 vehicles, check for normal operation of the Secondary Air Injection System (AIR).

SECONDARY AIR INJECTION SYSTEM CHECK:

Start engine.

NOTE:
At engine start-up with coolant temperature below 117~F (47~C), the Secondary Air Injection Pump (AIRP) operates continuously until the coolant temperature reaches 117~F (47~C).

Coolant temperature above 117~F (47~C).

At engine start-up with coolant temperature above 117~ F (47~C), the AIRP operates for a programmed period of time depending on coolant temperature. The AIRP then operates a second time for OBD monitoring.

NOTE:
If engine speed exceeds 900 RPM during the OBD monitoring phase. the AIRP switches off. When the engine returns to normal idle speed OBD monitoring will repeat and the AIRP will operate.

If Oxygen Sensor Feedback (H02 SFB) indicates excess oxygen (lean) in the exhaust while the AIRP is running the second time (OBD monitoring), the OBD test is passed. If Oxygen Sensor Feedback CH02 SFB) does not indicate excess oxygen (lean) while the AIRP is running the second time (OBD monitoring), the CHECK ENGINE light turns on and DTC 67 is flagged.

Refer to Service Manual section 17.3 for DTC 67 diagnosis information.

To erase the DTC from ECM memory:

Switch ignition OFF. Disconnect and reconnect the fuel injection ECM.