Important: To avoid misdiagnosis:
• Inspect for proper operation of the brake lamps. • Inspect for proper operation of the transmission range switch. • Inspect throttle linkage for mechanical binding which could cause the system to malfunction. • Inspect cruise control adjustment, should have minimum slack. • Inspect for stored Diagnostic Trouble Codes (DTCs) in the PCM. Refer to
Diagnostic System Check - Engine Controls
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. |
| • | When an over / undercharged battery condition DOES NOT exist. |
| • | With normal engine RPM. |
| • | Without high engine RPM. Refer to Powertrain Control Module Description in Engine Controls for additional information. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Cruise Control Schematics | ||||
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 40 |
3 | Probe the ignition 1 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 41 |
4 |
Does the test lamp illuminate on any of the circuits? | -- | Go to Step 18 | Go to Step 5 |
5 |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 19 |
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 21 |
7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 22 |
8 | Probe the cruise control cancel signal circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 9 |
9 |
Does the test lamp illuminate? | -- | Go to Step 37 | Go to Step 10 |
10 |
Does the test lamp illuminate? | -- | Go to Step 23 | Go to Step 39 |
11 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | -- | Go to Step 24 | Go to Step 12 |
12 | Probe the stoplamp switch signal circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 25 | Go to Step 13 |
13 | Press the brake pedal while monitoring the test lamp. Does the test lamp illuminate? | -- | Go to Step 14 | Go to Step 26 |
14 | Probe the cruise inhibit signal circuit with a test lamp that is connected to B+. Does the test lamp illuminate? | -- | Go to Step 28 | Go to Step 15 |
15 | Use a scan tool in order to command the cruise disable ON. Does the test lamp illuminate? | -- | Go to Step 16 | Go to Step 29 |
16 | Probe the cruise engaged output signal circuit with a DMM that is connected to a good ground. Does the voltage measure near the specified value? | B+ | Go to Step 17 | Go to Step 30 |
17 | Check the speedometer for proper operation. Does the speedometer operate properly? | -- | Go to Step 31 | Go to Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages and Console |
18 | Test the signal 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 47 | Go to Step 37 |
19 | Test the on/off signal circuit for a open, high resistance or short to ground and the ABS/TCC switch ignition positive voltage circuits 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 47 | Go to Step 20 |
20 | Test the ignition 1 voltage circuit of the cruise control switch for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 37 |
21 | Test the set/coast signal circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 37 |
22 | Test the resume/accel circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 37 |
23 | Test the cruise control cancel signal circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 32 |
24 | Test the cruise control cancel signal 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 47 | Go to Step 32 |
25 | Test the stoplamp switch signal 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 47 | Go to Step 33 |
26 | Test the stoplamp switch signal circuit for a open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 33 |
27 | Test the stop lamp/ auto trans shift lock control switch positive battery voltage circuit for a open, high resistance or short to ground. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 33 |
28 | Test the cruise inhibit signal 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 47 | Go to Step 36 |
29 | Test the cruise inhibit signal circuit for a open, 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 47 | Go to Step 36 |
30 | Test the cruise engaged output signal circuit for a open, high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 36 |
31 | Test the VSS signal circuit for an open or a high resistance between the cruise control module and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 36 |
32 | Inspect the TCC/Brake switch for proper adjustment. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 34 |
33 | Inspect the stoplamp/automatic transmission shift lock control switch is installed properly. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you find and correct the condition? | -- | Go to Step 47 | Go to Step 35 |
34 | Inspect for poor connections at the harness connector of the TCC/Brake 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 47 | Go to Step 42 |
35 | Inspect for poor connections at the harness connector of the stoplamp/automatic transmission shift lock 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 47 | Go to Step 43 |
36 | 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 47 | Go to Step 44 |
37 | Inspect for poor connections at the harness connector of the cruise control switch assembly. 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 47 | Go to Step 45 |
38 | 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 47 | Go to Step 46 |
39 | Repair the ignition positive voltage circuit if the TCC/Brake switch. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 47 | -- |
40 | Repair 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 47 | -- |
41 | Repair the ground circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 47 | -- |
42 | Replace the TCC/Brake (cruise release) switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | -- | Go to Step 47 | -- |
43 | Replace the stoplamp/automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | -- | Go to Step 47 | -- |
44 |
Important: The powertrain control module must be reprogrammed after replacement. Refer to Powertrain Control Module Programming in Engine Controls. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.6L. Did you complete the replacement? | -- | Go to Step 47 | -- |
45 | Replace the cruise control switch assembly. Refer to Steering Wheel Control Switch Assembly Replacement in Steering Wheel and Column. Did you complete the replacement? | -- | Go to Step 47 | -- |
46 | Replace the cruise control module. Refer to Cruise Control Module Replacement . Did you complete the replacement? | -- | Go to Step 47 | -- |
47 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? | -- | System OK | Go to Step 2 |
