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 MANUALSCHEVROLET2006SUBURBAN C1500, 5.3 ZREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1040 (TRAILER BRAKE CONTROL SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC C0890CIRCUIT/SYSTEM TESTING
2006 Chevrolet Suburban C1500, 5.3 Z
Circuit/System Testing
2006 Chevrolet Suburban C1500, 5.3 ZSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
All electrical components and accessories must be turned OFF and allowed to power down.
- Ignition OFF, disconnect the harness connector at the trailer brake controller switch panel.
- Test for less than 5 ohms of resistance between the ground circuit terminal 5 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the TBCM.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.
- If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the TBCM.
- If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the TBCM.
- If all circuits test normal, test or replace the trailer brake controller switch panel.
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.