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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1000 (ENGINE COOLING SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC P1A87: LOW STARTER/GENERATOR CONTROL MODULE COOLANT LEVELDIAGNOSTIC AIDS
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Diagnostic Aids

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Diagnostic Aids
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.

If the vehicle is on an extreme angle this DTC may set.

DTC P1A87

Step Action Yes No
Schematic Reference: Engine Cooling Schematics 
Connector End View Reference: Cooling System Connector End Views 
1 Was the Engine Cooling Diagnostic System Check performed? Go to Step 2  Go to Diagnostic System Check - Engine Cooling 
2
  1. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
  2. With a scan tool, observe the SGCM DTC list.
Is the DTC set as current DTC?		 Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3
IMPORTANT: Perform the programming procedure for the SGCM.
Replace the SGCM. Refer to Starter/Generator Control Module (SGCM) Replacement (5.3L Engine w/RPO HP2) in Engine Electrical.Did you complete the replacement?		 Go to Step 4  -
4
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 Go to Step 2  System OK
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.