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 for stored diagnostic trouble codes (DTCs) in the powertrain control module (PCM.) |
| • | 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 1 st gear is not indicated by the park/neutral position (PNP) switch. |
| • | When an over/undercharged battery condition does not exist. |
| • | With normal engine RPM. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the test lamp illuminate? | -- | Go to Step 3 | Go to Step 35 |
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 36 |
4 |
Does the test lamp illuminate on any of the circuits? | -- | Go to Step 16 | Go to Step 5 |
5 |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 17 |
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 19 |
7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 20 |
8 | Probe the cruise control release/clutch pedal position 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 go out? | -- | Go to Step 10 | Go to Step 22 |
10 | Probe the stop lamp 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 control inhibit input circuit with a test lamp that is connected to B+. Does the test lamp illuminate? | -- | Go to Step 25 | Go to Step 13 |
13 | Turn the ignition OFF. Reconnect cruise control module, disconnect the powertrain control module (PCM), turn the ignition ON, probe the inhibit circuit with a DDM to a good ground, does it measure near the specified value ? | B+ | Go to Step 14 | Go to Step 26 |
14 | Turn the ignition OFF. reconnect the PCM , disconnect the cruise control module turn the ignition ON, probe the cruise control 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 | Test the vehicle speed circuit between the cruise control module and the PCM for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 34 |
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 42 | Go to Step 33 |
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 42 | 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 42 | Go to Step 33 |
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 42 | Go to Step 33 |
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 42 | Go to Step 33 |
21 | Test the cruise control release/clutch pedal position 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 42 | Go to Step 28 |
22 | Test the cruise control release/clutch pedal position 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 42 | Go to Step 28 |
23 | Test the stop lamp 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 42 | Go to Step 29 |
24 | Test the stop lamp 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 42 | Go to Step 29 |
25 | Test the cruise inhibit 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 42 | Go to Step 32 |
26 | Test the cruise inhibit 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 42 | Go to Step 34 |
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 42 | Go to Step 32 |
28 | Inspect the cruise control release/clutch pedal position switch for proper adjustment. Refer to Clutch Pedal Cruise Control Release Switch Adjustment in Cruise Control. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 30 |
29 | Inspect the stop lamp switch for proper adjustment. Refer to Stop Lamp Switch Adjustment in Lighting Systems. Did you find and correct the condition? | -- | Go to Step 42 | Go to Step 31 |
30 | Inspect for poor connections at the harness connector of the cruise control release/clutch pedal position 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 42 | Go to Step 37 |
31 | Inspect for poor connections at the harness connector of the stop lamp 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 42 | Go to Step 38 |
32 | 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 42 | Go to Step 39 |
33 | Inspect for poor connections at the harness connector of the multifunction turn signal lever. 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 42 | Go to Step 40 |
34 | 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 42 | Go to Step 41 |
35 | 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 42 | -- |
36 | Repair the ground circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 42 | -- |
37 | Replace the cruise control release switch or clutch pedal position switch. Refer to Clutch Pedal Cruise Control Release Switch Replacement in Cruise Control. Did you complete the replacement? | -- | Go to Step 42 | -- |
38 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement and Stop Lamp Switch Adjustment in Lighting Systems. Did you complete the replacement? | -- | Go to Step 42 | -- |
39 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 42 | -- |
40 | Replace the multifunction turn signal lever. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column. Did you complete the replacement? | -- | Go to Step 42 | -- |
41 | Replace the cruise control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 42 | -- |
42 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? | -- | System OK | Go to Step 2 |
