Circuit Description
The powertrain control module (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:
| • | Engine has not been running long enough for 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. If the cruise engaged circuit indicates that 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 Failure 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
If the condition is intermittent, refer to Intermittent Conditions in Symptoms.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Testing if the PCM is correctly reading signal voltage.
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Testing for short on the Cruise Engaged Input circuit.
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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 | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
2 |
Is DTC P1585 also set? | -- | ||
With a scan tool, observe the Cruise Requested display. Does the Cruise Requested display indicate YES? | -- | |||
4 |
Does the scan tool indicate that DTC P1554 failed last test? | -- | Go to Diagnostic Aids | |
Does the Cruise Requested display indicate YES? | -- | |||
6 |
Did you find and correct the condition? | -- | ||
7 | Replace the Cruise Control Module. Refer to Cruise Control Module Replacement in Cruise Control. Is the action complete? | -- | -- | |
|
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||
9 |
Does the scan tool indicate that DTC P1554 passed? | -- | System OK |
