Diagnostic Aids
To avoid a misdiagnosis, inspect for the following:
| • | Proper operation of the stop lamps. Refer to Exterior Lighting Systems Description and Operation in Lighting Systems. |
| • | Proper adjustment of the cruise control cable. Refer to Cruise Control Cable Adjustment |
| • | The throttle linkage is not binding. |
Electromagnetic interference on the speed sensor signal circuit may cause erratic cruise control operation.
For an intermittent condition, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Conditions for Enabling Cruise Control
| • | The vehicle speed is greater than 40 km/h (25 mph). |
| • | The vehicle is not in PARK, REVERSE, NEUTRAL, or 1st gear. |
| • | The system voltage is within 9 volts and 16 volts. |
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views | ||||||||||
1 | Did you perform the Cruise Control Diagnostic System Check? | -- | Go to Step 2 | |||||||
2 |
Does the test lamp illuminate? | -- | Go to Step 3 | Go to Step 24 | ||||||
3 | Connect a test lamp between the ignition 1 voltage circuit and the ground circuit of the cruise control module. Does the test lamp illuminate? | -- | Go to Step 4 | Go to Step 25 | ||||||
4 |
Does the test lamp illuminate for any of the signal circuits listed above? | -- | Go to Step 15 | Go to Step 5 | ||||||
5 |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 16 | ||||||
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 20 | ||||||
7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 21 | ||||||
8 | Connect a test lamp between the TCC brake switch/cruise control release switch signal circuit and a good ground. Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 23 | ||||||
9 |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 26 | ||||||
10 | With a DMM, measure the voltage of the cruise control engaged signal circuit. Does the voltage measure near the specified value? | 9 Volts | Go to Step 11 | Go to Step 22 | ||||||
11 | With a DMM, measure the voltage at the vehicle speed signal circuit. Does the voltage measure near the specified value? | 9 Volts | Go to Step 12 | Go to Step 13 | ||||||
12 |
Does the voltage measure near the specified value? | 9 Volts | Go to Diagnostic Aids | Go to Step 27 | ||||||
13 | Test the vehicle speed signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
14 | Test the cruise control inhibit signal circuit for a short to ground, for an open, or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 29 | ||||||
15 | Test the signal circuit that illuminated the test lamp for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
16 | Test the cruise control On switch signal circuit for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 17 | ||||||
17 | Test the cruise control set/coast switch signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 18 | ||||||
18 | Test the cruise control resume/accel switch signal circuit for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 19 | ||||||
19 | Test the ignition 1 voltage circuit of the cruise control switch for an open, for a high resistance, or for short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
20 | Test the cruise control set/coast switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
21 | Test the cruise control resume/accel switch signal circuit for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 28 | ||||||
22 | Test the cruise control engaged signal circuit for an open, for a high resistance, or for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 27 | ||||||
23 | Repair the open or the high resistance in the TCC brake switch/cruise control release signal circuit between the fuse block - underhood and the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 33 | -- | ||||||
24 | Repair the open, the high resistance, or the short to ground in the ignition 1 voltage circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 33 | -- | ||||||
25 | Repair the open or the high resistance in the ground circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 33 | -- | ||||||
26 | Repair the open or the high resistance in the CHMSL supply voltage/stop lamp supply voltage circuit between the fuse block - underhood and the cruise control module. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 33 | -- | ||||||
27 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 30 | ||||||
28 | Inspect for poor connections at the harness connector of the cruise control switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 31 | ||||||
29 | Inspect for poor connections at the harness connector of the cruise control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 33 | Go to Step 32 | ||||||
30 |
Important: Program the replacement PCM. Replace the PCM. Refer to the appropriate procedure:
Did you complete the replacement? | -- | Go to Step 33 | -- | ||||||
31 | Replace the cruise control switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column. Did you complete the replacement? | -- | Go to Step 33 | -- | ||||||
32 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Did you complete the replacement? | -- | Go to Step 33 | -- | ||||||
33 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? | -- | System OK | Go to Step 2 | ||||||
