GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2004 🢒 Regal 🢒 DTC 🢒 DTC P1554

Circuit Description

The PCM inhibits cruise control operation when certain conditions are detected.

The PCM removes the ground from the cruise control inhibit signal circuit in order to disengage cruise control operation. The cruise control module monitors the cruise control inhibit signal circuit in order to determine when to inhibit cruise.

When the cruise control module (CCM) activates cruise control operation, the CCM provides a ground for the cruise control engaged signal circuit. The PCM monitors the cruise control engaged signal circuit in order to determine that cruise control is engaged.

Conditions for Running the DTC

The PCM inhibits cruise control operation by removing the ground from the cruise control inhibit signal circuit.

Conditions for Setting the DTC
    • The PCM detects a cruise control engaged signal from the cruise control module, while inhibiting cruise control operation.
    • The above condition is present for more than 1 second.

Action Taken When the DTC Sets

    • The PCM does not illuminate the malfunction indicator lamp (MIL).
    • The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

Conditions for Clearing the MIL/DTC
    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 warm-up cycles.
    • The PCM receives a clear code command from the scan tool.

Step

Action

Yes

No

Schematic Reference: Cruise Control Schematics

1

Did you perform the Cruise Control Diagnostic System Check?

Go to Step  2

Go to Diagnostic System Check - Cruise Control

2
  1. Install a scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. With the scan tool observe the Cruise Active parameter in the PCM Engine Data 1 data list.

Does the Cruise Active parameter display Engaged?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3
  1. Turn the ignition OFF.
  2. Disconnect the cruise control module.
  3. Turn the ignition ON, with the engine OFF.
  4. With the scan tool, observe the Cruise Active parameter.

Does the Cruise Active parameter display Engaged?

Go to Step 4

Go to Step 5

4

Test the cruise control engaged signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step  9

Go to Step 6

5

Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step  9

Go to Step 7

6

Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

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

--

8

Important:: Program the replacement PCM.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 3.1L or to Powertrain Control Module Replacement in Engine Controls - 3.8L.

Did you complete the replacement?

Go to Step  9

--

9
  1. Use a scan tool in order to clear the DTC.
  2. Operate the vehicle within the conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step  2

System OK