The PCM has the ability to inhibit cruise control operation if conditions exist that would make cruise operation undesirable. The following conditions may inhibit cruise control operation:
• | Engine speed is too high or too low. |
• | Vehicle speed is too high or too low. |
• | Traction control has been active for longer than 1 second. |
• | 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.
The PCM is commanding the cruise control module to inhibit cruise control operation.
The PCM detects a cruise engaged signal from the cruise control module, while inhibiting cruise control operation.
• | The PCM will not illuminate the malfunction indicator lamp (MIL). |
• | The PCM will store the conditions present when the DTC set as Failure Records data only. |
• | 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's Clear DTC Information function. |
If the conditions is intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
The numbers below refer to the step numbers on the Diagnostic Table.
Tests the PCM's ability to correctly read the signal voltage.
Tests for a short on the cruise engaged input circuit.
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.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Cruise Control Schematics | |||
1 | Did you perform A Diagnostic System Check - Cruise Control? | Go to Step 2 | |
2 |
Is DTC P1585 also set? | Go to DTC P1585 | Go to Step 3 |
With a scan tool, observe the Cruise Requested display. Does the Cruise Requested display indicate YES? | Go to Step 5 | Go to Step 4 | |
4 |
Does the scan tool indicate that DTC P1554 failed this ignition? | Go to Step 5 | Go to Diagnostic Aids |
Does the Cruise Requested display indicate YES? | Go to Step 6 | Go to Step 7 | |
6 |
Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
7 | Replace the Cruise Control Module. Refer to Cruise Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- |
Important: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement 3.4L or DTC P0172 in Engine Controls-3.8L. Replace the PCM. Refer to Powertrain Control Module Replacement 3.4L or DTC P0172 in Enigine Controls-3.8L. Did you complete the replacement? | Go to Step 9 | -- | |
9 |
Does the DTC reset? | Go to Step 2 | System OK |