For 1990-2009 cars

### Circuit Description

The cruise control switch is an input to the engine control module (ECM). The ECM monitors the cruise control switch signal circuit in order to detect when a cruise control function has been requested. The ECM detects a specific voltage signal on the cruise control set/coast and resume/accelerate switch signal circuit when a cruise control function switch is activated, with each switch having a different predetermined voltage value.

### Conditions for Setting the DTC

• | The engine is running.

• | Battery voltage is greater than 7.9956 voltage.

• | The ECM detects the switch is switching too quickly or stuck for too long.

### Action Taken When the DTC Sets

• | The Malfunction Indicator Lamp (MIL) will not illuminate.

• | The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.

• | A history DTC is stored.

• | The A/C compressor operation will be disabled while the low voltage indication exists.

### Conditions for Clearing the MIL/DTC

• | A history DTC will clear after 40 consecutive warm up cycles without a fault.

• | DTC(s) can be cleared by using the scan tool.

• | Disconnecting the ECM battery feed for more than 10 seconds.

### Diagnostic Aids

Perform the following in order to avoid misdiagnosis:

• | Rotate the steering wheel to both steering stops and activate each cruise control switch separately. With a scan too, observe the associated cruise control switch parameter. This will help eliminate the possibility of an internally open or shorted contact coil.

• | Ensure that the resume/accel switch is not stuck or sticking in the engaged position.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step determines if condition is present

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Turn the cruise On/Off control switch ON.
4. With the scan tool, observe the Cruise Resume/Accel. Switch parameter.

Does the Cruise Resume/Accel. Switch parameter display On?

--

Go to Step 3

Go to Diagnostic Aids

3 |

1. Turn OFF the ignition.
2. Disconnect the cruise control switch connector.
3. Turn ON the ignition, with the engine OFF.
4. With the scan tool, observe the Cruise Resume/Accel. Switch parameter.

Does the Cruise Resume/Accel. Switch parameter display On?

--

Go to Step 4

Go to Step 5

4 | Test the cruise control resume/accel switch signal circuit for a short to voltage. 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 switch. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8
6 | Inspect for poor connections at the harness connector of the engine control module (ECM). Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7
7 | Replace the ECM. Did you complete the replacement? | -- | Go to Step 9 | --
8 | Replace the cruise control switch. Did you complete the replacement? | -- | Go to Step 9 | --
9 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Setting the DTC.

Does the DTC reset?

--

Go to Step 2

System OK