Cruise Control Inoperative/Malfunctioning (WO/ETC) Diagnostic Aids Important: Perform the following in order to avoid misdiagnosis. Inspect for proper operation of brake lamps and clutch switch, if equipped. 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 cable adjustment, should have minimum slack. EMI on the speed sensor signal circuit may cause erratic cruise control operation. Conditions for Enabling Cruise Control The vehicle speed is greater than 40 km/h (25 mph). Step Action Value(s) Yes No Schematic Reference: Cruise Control Schematics 1 2 3 Did you perform the Cruise Control Diagnostic System Check? Step 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. 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 Diagnostic System Check - Cruise Control Step 3 Step 33 Step 4 Step 34
module. 4 5 6 7 8 9 10 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 signal circuits with a test lamp that is connected to a good ground. Does the test lamp illuminate on any of the circuits? 1. Turn ON the ignition, with the engine OFF. 2. Turn ON the cruise control. 3. Probe the cruise control on/off signal circuit with a test lamp that is connected to a good ground. 1. Probe the cruise control set/coast signal circuit with a test lamp that is connected to a good ground. 2. Press and hold the SET/COAST switch. 1. Probe the cruise control resume/accelerate signal circuit with a test lamp that is connected to a good ground. 2. Press and hold the RESUME/ACCEL switch. Probe the TCC/brake, cruise release signal circuit with a test lamp that is connected to a good ground. Is the vehicle equipped with a manual transmission? 1. Turn OFF the ignition. 2. Disconnect the clutch pedal position (CPP) switch. Step 16 Step 5 Step 6 Step 17 Step 7 Step 19 Step 8 Step 20 Step 11 Step 9 Step 10 Step 21 Step 22 Step 21
3. Turn ON the ignition, with the engine OFF. 4. Probe the CPP switch harness connector ignition positive voltage circuit with a test lamp connected to a good ground. 11 Press the brake pedal while monitoring the test lamp. Step 23 Step 12 12 Probe the stoplamp switch signal circuit with a test lamp that is connected to a good ground. Step 24 Step 13 13 Press the brake pedal while monitoring the test lamp. Step 14 Step 25 14 Probe the cruise engaged signal circuit with a DMM that is connected to a good ground. B+ Does the voltage measure near the specified value? Step 15 Step 26 15 Check the speedometer for proper operation. Does the speedometer operate properly? Step 27 Symptoms - Instrument Panel, Gages and Console in Instrument Panel, Gages, and Console 16 Test the circuit that illuminated the test lamp for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Step 30 17 Test the cruise control on/off signal circuit for an open, high resistance or short to ground and the set/coast, resume/accel signal circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Step 18
18 19 20 21 22 23 24 25 Test the ignition positive voltage circuit of the cruise control switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Test the set/coast switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Test the resume/accelerate switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Test the TCC/ brake, cruise release signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Test the TCC/ brake, cruise release signal circuit for an open or a high resistance between the CPP switch and the cruise control module. Refer to Circuit Testing and Wiring Repairs in Test the TCC/ brake, cruise release switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Test the stoplamp switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Test the stoplamp switch signal circuit for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Step 30 Step 30 Step 30 Step 28 Step 35 Step 28 Step 28 Step 28
26 27 28 29 30 31 Test the cruise engaged signal circuit for an open, a high resistance, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Test the speed sensor circuit for an open or a high resistance between the PCM and cruise control module. Refer to Circuit Testing and Wiring Repairs in 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 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in 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 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 Step 29 Step 31 Step 36 Step 37 Step 38 Step 39 32 Inspect for poor connections at the Step 35
harness connector of the CPP switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in 33 34 35 36 37 38 Repair the ignition positive voltage circuit of the cruise control module. Refer to Wiring Repairs in Wiring Systems. Repair the ground circuit of the cruise control module. Refer to Wiring Repairs in Replace the CPP switch. Refer to Clutch Pedal Engine Start Switch Replacement in Clutch. Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Important: The PCM must be reprogrammed after replacement. Refer to Powertrain Control Module Programming in Engine Controls - 4.3L, or Powertrain Control Module Programming in Engine Controls - 4.8L, 5.3L, 6.0L. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.3L, or Powertrain Control Module Replacement in Engine Controls - 4.8L, 5.3L, 6.0L. Replace the cruise control switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column. 39 Replace the cruise control module.
Refer to Cruise Control Module Replacement. 40 Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? System OK Step 2