Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 958 (CRUISE CONTROL SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESCRUISE CONTROL INOPERATIVE/MALFUNCTIONING (4.3L)CONDITIONS FOR ENABLING CRUISE CONTROL
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Conditions for Enabling Cruise Control
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Conditions for Enabling Cruise Control
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- 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 between 12 volts and 16 volts.
Cruise Control Inoperative/Malfunctioning (4.3L)
| Step | Action | Value | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Cruise Control Schematics Connector End View Reference: Cruise Control Connector End Views or Powertrain Control Module (PCM) Connector End Views in Engine Controls - 4.3L |
||||
| 1 | Did you perform the Cruise Control Diagnostic System Check? | - | Go to Step 2 | Go to Diagnostic System Check - Cruise Control |
| 2 |
|
- | Go to Step 3 | Go to Step 5 |
| 3 | Connect a test lamp between the ignition 3 voltage circuit and the ground circuit of the cruise control module. Does the test lamp illuminate? |
- | Go to Step 4 | Go to Step 22 |
| 4 |
|
- | Go to Step 12 | Go to Step 6 |
| 5 |
|
- | Go to Step 13 | Go to Step 21 |
| 6 |
|
- | Go to Step 7 | Go to Step 14 |
| 7 |
|
- | Go to Step 8 | Go to Step 16 |
| 8 |
|
- | Go to Step 9 | Go to Step 17 |
| 9 | Connect a test lamp between the stop lamp supply voltage circuit and a good ground. Refer to Circuit Testing
in Wiring Systems. Does the test lamp illuminate? |
- | Go to Step 10 | Go to Step 19 |
| 10 | With a DMM, measure the voltage from the vehicle speed signal circuit to a good ground. Refer to Circuit Testing
in Wiring Systems. Does the voltage measure at the specified value? |
B+ | Go to Step 11 | Go to Step 20 |
| 11 | With a DMM, measure the voltage from the cruise control engaged signal to a good ground. Refer to Circuit Testing
in Wiring Systems. Does the voltage measure at the specified value? |
B+ | Go to Step 25 | Go to Step 18 |
| 12 | 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 29 | Go to Step 24 |
| 13 | Test the signal circuit that illuminated the test lamp 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 29 | Go to Step 24 |
| 14 | Test the cruise control on/off 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 29 | Go to Step 15 |
| 15 | Test the ignition 3 voltage circuit for an open or for a high resistance between S204 and the multifunction switch. Refer to Circuit Testing
and to Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 29 | Go to Step 24 |
| 16 | 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 29 | Go to Step 24 |
| 17 | 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 29 | Go to Step 24 |
| 18 | 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 29 | Go to Step 23 |
| 19 | Repair the open, the high resistance, or the short to ground in the stop lamp supply voltage circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 29 | - |
| 20 | Repair the open or the high resistance in the vehicle speed signal circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 29 | - |
| 21 | Repair the open, the high resistance, or the short to ground in the ignition 3 voltage circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 29 | - |
| 22 | 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 29 | - |
| 23 | 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 29 | Go to Step 26 |
| 24 | Inspect for poor connections at the harness connector of the multifunction 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 29 | Go to Step 27 |
| 25 | 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 29 | Go to Step 28 |
| 26 |
IMPORTANT:
Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement
in Engine Controls - 4.3L.Did you complete the replacement? |
- | Go to Step 29 | - |
| 27 | Replace the multifunction switch. Refer to Multifunction, Turn Signal Switch Replacement
in Steering Wheel and Column. Did you complete the replacement? |
- | Go to Step 29 | - |
| 28 | Replace the cruise control module. Refer to Cruise Control Module Replacement (4.3L Engine) . Did you complete the replacement? |
- | Go to Step 29 | - |
| 29 | Operate the vehicle within the conditions for cruise control operation. Does the cruise control system operate correctly? |
- | System OK | Go to Step 2 |
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.