For 1990-2009 cars

### Diagnostic Aids

Important: Perform the following in order to avoid misdiagnosis.

• | Inspect for proper operation of brake lamps.

• | Inspect throttle linkage for mechanical binding which could cause the system to malfunction.

• | Inspect cruise control cable adjustment, should have minimum slack.

• | Inspect for stored Diagnostic Trouble Codes (DTCs) in the PCM. Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls.

• | EMI on the speed sensor signal circuit may cause erratic cruise control operation.

### Conditions for Enabling Cruise Control

• | When vehicle speed is more than 40 km/h (25 mph)

• | When PARK, REVERSE, NEUTRAL, or 1st gear is not indicated by the Park Neutral Position Switch.

• | When an over/undercharged battery condition does not exist.

• | With normal engine RPM.

• | Without high engine RPM (fuel cut-off). Refer to Fuel Metering Modes of Operation in Engine Controls for additional information.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform A Diagnostic Systems Check - Cruise Control? | -- | Go to Step 2 | Go To Diagnostic System Check - Cruise Control
2 |

1. Turn OFF the ignition.
2. Disconnect the cruise control module.
3. Turn ON the ignition, with the engine OFF.
4. Probe the ignition positive voltage circuit of the cruise control module with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 3

Go to Step 36

3 | Probe the ignition positive voltage circuit of the cruise control module with a test lamp that is connected to the ground circuit of the cruise control module. Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 37
4 |

1. Turn ON the ignition, with the engine OFF.
2. Turn OFF the cruise control.
3. Probe the on/off, the set/coast, and the resume/accelerate circuits with a test lamp that is connected to a good ground.

Does the test lamp illuminate on any of the circuits?

--

Go to Step 16

Go to Step 5

5 |

1. Turn ON the ignition, with the engine OFF.
2. Turn ON the cruise control.
3. Probe the on/off circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 17

6 |

1. Probe the set/coast circuit with a test lamp that is connected to a good ground.
2. Press and hold the SET/COAST switch.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 19

7 |

1. Probe the resume/accelerate circuit with a test lamp that is connected to a good ground.
2. Press and hold the RESUME/ACCEL switch.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 20

8 | Probe the cruise control release switch circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 21
9 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | -- | Go to Step 22 | Go to Step 10
10 | Probe the brake switch circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 23 | Go to Step 11
11 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | -- | Go to Step 12 | Go to Step 24
12 | Probe the cruise disable/enable circuit with a test lamp that is connected to B+. Does the test lamp illuminate? | -- | Go to Step 25 | Go to Step 13
13 | Use a scan tool in order to command the cruise inhibit/enable OFF. Does the test lamp illuminate? | -- | Go to Step 14 | Go to Step 26
14 | Probe the cruise engaged output circuit with a DMM that is connected to a good ground. Does the voltage measure near the specified value? | B+ | Go to Step 15 | Go to Step 27
15 |

1. Raise and suitably support the vehicle.
2. Block one of the drive wheels.
3. Place the Transaxle/Transmission Selector in drive.
4. Set the DMM to the AC scale.
5. Probe the VSS signal circuit with a DMM that is connected to a good ground.
6. Rotate one of the drive wheels.
7. Observe the DMM.

Does the voltage displayed on the DMM vary?

--

Go to Step 35

Go to Step 28

16 | Test the circuit that illuminated the test lamp for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 34
17 | Test the on/off circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 18
18 | Test the ignition positive voltage circuit for an open or high resistance between the cruise control module and the cruise control switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 34
19 | Test the set/coast circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 34
20 | Test the resume/accelerate circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 34
21 | Test the cruise control release switch circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 29
22 | Test the cruise control release switch circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 29
23 | Test the brake (stoplamp) switch circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 30
24 | Test the brake (stoplamp) switch circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 30
25 | Test the cruise disable/enable circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 33
26 | Test the cruise disable/enable circuit for an open, a high resistance, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 33
27 | Test the cruise engaged output circuit for an open, a high resistance, or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 33
28 | Test the speed sensor circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 33
29 | Inspect the cruise control release switch for proper adjustment. Refer to Cruise Release Switch Adjustment . Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 31
30 | Inspect the brake (stoplamp) switch for proper adjustment. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 32
31 | Inspect for poor connections at the harness connector of the cruise control release switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 38
32 | Inspect for poor connections at the harness connector of the brake (stoplamp) switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 39
33 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 40
34 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 41
35 | Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 42
36 | Repair the ignition positive voltage circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | --
37 | Repair the ground circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | --
38 | Replace the cruise control release switch. Refer to Cruise Control Release Switch Replacement and Cruise Release Switch Adjustment . Did you complete the replacement? | -- | Go to Step 43 | --
39 | Replace the brake (stoplamp) switch. Refer to Stop Lamp Switch Replacement and Stop Lamp Switch Adjustment in Hydraulic Brakes. Did you complete the replacement? | -- | Go to Step 43 | --
40 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Did you complete the replacement? | -- | Go to Step 43 | --
41 | Replace the multifunction turn signal lever. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle . Did you complete the replacement? | -- | Go to Step 43 | --
42 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Did you complete the replacement? | -- | Go to Step 43 | --
43 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? | -- | System OK | Go to Step 2