GM Service Manual Online
For 1990-2009 cars only

Object Number: 404127  Size: SF
Engine Controls Components
OBD II Symbol Description Notice
Cell 14: Engine Grounds G100, G111 and G113
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The powertrain control module (PCM) can disable the cruise control if it detects conditions which would make the cruise control operation undesirable. The following conditions can cause the PCM to inhibit the cruise control:

    • The engine is not running long enough for cruise control operation.
    • The transaxle range switch indicates that park, neutral, low, or reverse gear is selected.
    • The engine speed is too high or too low.
    • The vehicle speed is too high or too low.
    • The antilock brake system (ABS) system is active for more than 2 seconds.
    • The vehicle acceleration or deceleration rate is too high.

If any of these conditions are present, the PCM will interrupt the ground on the cruise inhibit circuit in order disengage the cruise control. If the cruise status signal indicates that cruise control is still engaged while the PCM is inhibiting cruise control operation, DTC P1554 will set.

Conditions for Setting the DTC

    • The PCM is commanding the SMCC module in order to inhibit the cruise control operation. The cruise inhibit circuit is not grounded.
    • The Cruise Status circuit signal indicates that the cruise control is engaged.
    • The above conditions are present for more than 1 second.

Action Taken When the DTC Sets

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 malfunction free warm-up cycles.
    • The PCM receives a clear code command from the scan tool.

Diagnostic Aids

Inspect for the following conditions:

Many situations may lead to an intermittent condition. Perform each inspection or test as directed.

Important: :  Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

    • Loose terminal connection
       -  Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.
       -  Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.
    • Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.
    •  Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.

Test Description

The numbers below refer to the step numbers on the Diagnostic Table.

  1. This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read-only memory (EEPROM). When you replace the PCM, you must program the new PCM.

DTC P1554 - Cruise Control Status Circuit

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Is DTC P1585 also set?

--

Go to DTC P1585 Cruise Control Inhibit Output Circuit

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the cruise control module.
  3. Turn ON the ignition, with the engine OFF.
  4. Use a DMM in order measure the voltage between the cruise status circuit at the cruise control module harness connector and ground.

Is the voltage more than the specified value?

7V

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Reconnect the cruise control module.
  3. Disconnect the PCM.
  4. Turn ON the ignition, with the engine OFF.
  5. Probe the cruise engaged status circuit at the PCM harness connector with a test lamp connected to B+.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 7

5

  1. Test the cruise status circuit for an open or faulty connection at the PCM.
  2. If you find a problem, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 8

6

Replace the cruise control module. Refer to Cruise Control Module Replacement in Cruise Control.

Did you complete the replacement?

--

Go to Step 9

--

7

Important:: The replacement PCM must be programmed.

Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM.

Did you complete the replacement?

--

Go to Step 9

--

8

Locate and repair the short to ground in the cruise engaged status circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 9

--

9

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

Does DTC reset?

--

Go to Step 2

System OK