P1554

CIRCUIT DESCRIPTION

Schematic:

The PCM has the ability to inhibit cruise control if conditions exist that would make cruise operation undesirable. The following conditions may inhibit cruise control operation:
^ The engine has not been running long enough for cruise control operation.
^ The engine speed is too high or too low.
^ The vehicle speed is too high or too low.
^ The traction control has been active for longer than 1 second.
^ The vehicle acceleration or deceleration rate is too high.

If any of these conditions are present, the PCM will remove the ground from the cruise inhibit circuit If the cruise engaged circuit indicates that the cruise control is still engaged while the PCM is inhibiting cruise control operation,.DTC P1554 will set.

CONDITIONS FOR RUNNING THE DTC
The PCM is commanding the cruise control module to inhibit cruise control operation (cruise inhibit circuit is not grounded).

CONDITIONS FOR SETTING THE DTC
The PCM detects a cruise engaged signal from the cruise control module, while inhibiting cruise control operation.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store the conditions present when the DTC set as Fail Records data only.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool Clear DTC Information function.

DIAGNOSTIC AIDS

NOTE: Refer to Connector Test Adapter Kit J 35616-A Notice in Service Precautions.

Inspect the wiring harness for damage. It the harness appears to be OK, observe the cruise status display on the scan tool while moving connectors and wiring harnesses related to the cruise control module. A change in the display will indicate the location of the malfunction. If a problem is found, repair as necessary. Refer to Wiring Repairs in Diagrams.

Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.

TEST DESCRIPTION

Steps 1 - 9:

The numbers below refer to the step numbers on the diagnostic table.
3. This step determines if the PCM is reading the signal voltage correctly.
5. This step looks for a short on the cruise engaged input circuit.
8. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.