For 1990-2009 cars
Engine Controls Components
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The powertrain control module (PCM) inhibits cruise control operation when certain conditions are not appropriate for cruise control operation. The PCM removes the ground from the cruise control inhibit signal circuit in order to disengage cruise control operation.

### Conditions for Running the DTC

The PCM is commanding the SMCC module to inhibit cruise control operation (Cruise Inhibit circuit not grounded).

### Conditions for Setting the DTC

• | The Cruise Status circuit signal indicates that cruise control is engaged.

• | The above conditions are present for longer 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

Check for the following conditions:

• | Poor connection at the PCM.

| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

• | Damaged harness.

| Inspect the wiring harness for damage. If the harness appears to be OK, observe the Cruise Status display on the scan tool while moving connectors and wiring harnesses related to the Stepper Motor Cruise Control module. A change in the display will indicate the location of the malfunction.

If DTC P1554 cannot be duplicated, the information included in the Failure records data can be useful in determining how many ignition cycles have passed since the DTC was last set.

### 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 the PCM is being replaced, the new PCM must be programmed. Refer to PCM Replacement/Programming .

#### DTC P1554 - Cruise Control Status Circuit

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | Is DTC P1662 also set? | -- | Go to DTC P1662 Cruise Control Inhibit Output Circuit | Go to Step 3
3 |

1. Turn OFF the ignition switch.
2. Disconnect the cruise control module.
3. Turn ON the ignition switch.
4. Measure the voltage between the cruise status circuit at the cruise control module harness connector and ground using a digital multimeter.

Is the voltage near the specified value?

B+

Go to Step 4

Go to Step 5

4 |

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

Is the test lamp ON?

--

Go to Step 6

Go to Step 7

5 |

1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. For Pontiac or Oldsmobile - Probe the cruise engaged status circuit at the PCM harness connector with a test lamp connected to B+.

For Buick - Observe the instrument cluster "Cruise" indicator.

4. Turn ON the ignition.

Is the test lamp or the indicator ON?

--

Go to Step 8

Go to Step 7

6 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Is action complete? | -- | Go to Step 9 | --
7 | Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | Go to Step 9 | --
8 | Locate and repair short to ground in the cruise engaged status circuit. Refer to Wiring Repairs . Is the action complete? | -- | Go to Step 9 | --
9 |

1. Clear DTC P1554.
2. Start the engine and observe the DTCs.

Did DTC P1554 set?

--

Go to Step 2

System OK