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.
Test Description
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Test Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
- 8: This step tests the center high mounted stop lamp (CHMSL) supply voltage/stop lamp supply voltage circuit for an open or for a high resistance between the stop lamp switch and the throttle actuator control (TAC) module.
- 9: This step tests the cruise control set/coast switch signal circuit for an open or for a high resistance.
- 10: This step tests the cruise control resume/accel switch signal circuit for an open or for a high resistance.
- 11: This step tests the ignition 3 voltage circuit for an open, for a short to ground, or for a high resistance.
- 29: DTCs will set in the powertrain control module (PCM) when you perform this table.
Cruise Control Inoperative/Malfunctioning (5.3L)
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference : Cruise Control Schematics Connector End View Reference: Powertrain Control Module (PCM) Connector End Views in Engine Controls - 4.8L, 5.3L, and 6.0L |
|||
| 1 | Did you perform the Diagnostic System Check - Cruise Control? | Go to Step 2 | Go to Diagnostic System Check - Cruise Control |
| 2 |
|
Go to Step 4 | Go to Step 3 |
| 3 |
|
Go to Step 22 | Go to Step 13 |
| 4 |
|
Go to Step 5 | Go to Step 11 |
| 5 |
|
Go to Step 6 | Go to Step 9 |
| 6 |
|
Go to Step 7 | Go to Step 10 |
| 7 | Do the stop lamps operate properly? | Go to Step 8 | Go to Stop Lamps Inoperative in Lighting Systems |
| 8 |
|
Go to Diagnostic Aids | Go to Step 21 |
| 9 |
|
Go to Step 22 | Go to Step 19 |
| 10 |
|
Go to Step 22 | Go to Step 20 |
| 11 |
|
Go to Step 12 | Go to Step 15 |
| 12 |
|
Go to Step 22 | Go to Step 18 |
| 13 | Test the cruise control on switch signal circuit 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 14 |
| 14 |
|
Go to Step 24 | Go to Step 23 |
| 15 | 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 29 | Go to Step 16 |
| 16 | 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 29 | Go to Step 17 |
| 17 | Test the cruise control on 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 29 | Go to Step 25 |
| 18 | Test the cruise control on 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 23 |
| 19 | 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 23 |
| 20 | 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 23 |
| 21 | Test the center high mounted stop lamp (CHMSL) supply voltage/stop lamp supply voltage circuit for an open or for a high resistance between the stop lamp switch and the throttle actuator control (TAC) module. 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 |
| 22 | 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 29 | Go to Step 26 |
| 23 | Inspect for poor connections at the harness connector of the TAC 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 27 |
| 24 | 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 28 |
| 25 | Repair the open, the high resistance, or the short to ground in the ignition 3 voltage circuit. Refer to Circuit Testing
and to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 29 | - |
| 26 | Replace the cruise control switch. Refer to Multifunction, Turn Signal Switch Replacement
in Steering Wheel and Column. Did you complete the replacement? |
Go to Step 29 | - |
| 27 | Replace the TAC module. Refer to Throttle Actuator Control (TAC) Module Replacement
in Engine Controls - 4.8L, 5.3L, and 6.0L. Did you complete the replacement? |
Go to Step 29 | - |
| 28 |
IMPORTANT:
Program the replacement PCM. Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement
in Engine Controls - 4.8L, 5.3L, and 6.0L.Did you complete the replacement? |
Go to Step 29 | - |
| 29 |
|
System OK | Go to Step 2 |
RENDER: 1.0x
NO RELATED
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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.