For 1990-2009 cars
Engine Controls Components
Cell 20: Cruise Control
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The cruise control switch release is used to disable the cruise control whenever the brake is applied. The switch gets its power from the ignition circuit at the stoplamp switch. The engine control module ECM monitors the B+ voltage for the cruise control and stoplamp switch circuits.

### Conditions for Setting the DTC

The cruise release signal does not match the stop lamp signal at least 20 times.

### Conditions for Running

Ignition is ON.

### Action Taken When the DTC Sets

The ECM will not illuminate the malfunction indicator lamp (MIL).

### Conditions for Clearing the MIL/DTC

• | The DTC clears after forty consecutive warm-up cycles in which there are no failures reported by this diagnostic or any other non-emission related diagnostic.

• | The ECM battery voltage is interrupted.

• | The scan tool clears the MIL/DTC.

### Diagnostic Aids

Notice: Using the J 35616-A Connector Test Adapter Kit will prevent damage to the harness connector terminals.

Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.

Check for the following conditions:

• | Poor connections at the ECM or at the component--Inspect the harness connectors for a poor terminal to wire connection. Refer to Engine Control Module Diagnosis , Checking Terminal Contact, for the proper procedure.

• | Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the scan tool while moving the related connectors and the wiring harnesses. A change in the display may help locate the fault.

Refer to Symptoms for the Intermittents.

#### DTC P0571 Cruise Brake Switch

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 |

1. Turn the ignition ON.
2. Monitor the Cruise Release Brake Switch and the Stoplamp Brake Switch Input displays on the scan tool.
3. Depress and release the brake pedal several times while observing the scan tool displays.

Do both displays indicate the state of the brake pedal correctly?

--

Go to Diagnostic Aids

Go to Step 3

3 | Is the Cruise Release Brake Switch display incorrect? | -- | Go to Step 4 | Go to Step 8
4 | Does the Cruise Release Brake Switch display always indicate Applied? | -- | Go to Step 5 | Go to Step 7
5 |

1. Disconnect the cruise control release switch.
2. With a J 35616-200 unpowered test lamp connected to ground, probe the cruise control release switch power feed circuit pin 1.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 13

6 |

1. Jumper the cruise control release switch terminals together using a fused jumper.
2. Monitor the Cruise Release Brake Switch display on the scan tool.

Does the display indicate the state of the brake pedal as Released?

--

Go to Step 15

Go to Step 12

7 |

1. Disconnect the cruise control release switch.
2. Monitor the Cruise Release Brake Switch display on the scan tool.

Does the display indicate the state of the brake pedal as Applied?

--

Go to Step 15

Go to Step 14

8 | Observe the exterior brake lights while depressing and releasing the brake pedal. Do the exterior brake lights operate normally? | -- | Go to Step 12 | Go to Step 9
9 |

1. Disconnect the stop lamp switch.
2. Observe the exterior brake lights with the stop lamp switch disconnected.

Are the exterior brake lights illuminated?

--

Go to Step 14

Go to Step 10

10 | With a J 35616-200 unpowered test lamp connected to ground, probe the stop lamp switch power feed circuit pin 1. Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 13
11 |

1. Jumper the stop lamp switch terminals 1 and 2 together using a fused jumper.
2. Monitor the Cruise Release Brake Switch display on the scan tool.

Does the display indicate the state of the brake pedal as Applied?

--

Go to Step 16

Go to Step 12

12 |

1. Turn the ignition OFF.
2. Disconnect the ECM.
3. Using the J 39200 DMM, check the signal circuit for continuity between the switch and the ECM. The DMM should indicate very low resistance.
4. Inspect for proper terminal contact at the ECM connector.
5. Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found and repaired?

--

Go to Step 18

Go to Step 17

13 |

1. Inspect for an open fuse. If an open fuse is indicated, repair the cause of the short.
2. Inspect for proper voltage to the fuse.
3. If a problem was not found in the previous inspections, use the J 39200 DMM and check the switch power feed circuit for continuity between the switch and the fuse. The DMM should indicate very low resistance.
4. Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 18

--

14 | Repair the signal circuit shorted to B+. Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | Go to Step 18 | --
15 | Replace the cruise control release switch. Refer to Cruise Control Switch Replacement . Is the action complete? | -- | Go to Step 18 | --
16 | Replace the stop lamp switch. Refer to stop lamp switch replacement in Body and Accessories. Is the action complete? | -- | Go to Step 18 | --
17 | Important:

• | Perform the Idle Learn Procedure when replacing the ECM or throttle body.

• | This vehicle is equipped with a theft deterrent module that interfaces with the engine control module (ECM). Program the new ECM with the frequency code of the theft deterrent module that is currently on the vehicle.

Replace the ECM. Refer to Engine Control Module Replacement/Programming .

Is the action complete?

--

Go to Step 18

--

18 |

1. Use a scan tool in order to clear the DTCs.
2. Start the engine.
3. Allow the engine to idle until the engine reaches the normal operating temperature.
4. Select DTC and the Specific DTC function.
5. Enter the DTC number that was set.
6. Operate the engine within the Conditions for Setting this DTC until the scan tool indicates the diagnostic Ran.

--

Go to Step 2

Go to Step 19

19 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK