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 MANUALSCHEVROLET1987HI-CUBE 6.2 J, 475/M40REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 18 (ENGINE CONTROLS - TESTS W/CODES - 7.4L)TROUBLE CODE CHARTSCODE 13, OPEN OXYGEN SENSOR CIRCUITDIAGNOSTIC AIDS
1987 Chevrolet Hi-Cube 6.2 J, 475/M40
Diagnostic Aids
1987 Chevrolet Hi-Cube 6.2 J, 475/M40SECTION Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Suburban, 1994 GMC Rally Camper Special, and 1994 GMC Rally. However, it is still accessible from the selected car via links, so may be relevant.
Verify a clean, tight connection for the sensor ground. An open circuit at sensor signal terminal or ground terminal will result in a Code 13.
CODE 13 TERMINAL & CIRCUIT WIRING IDENTIFICATION
| Application | PCM Terminal | Wire Color | ||
|---|---|---|---|---|
| "C" & "K" Series | ||||
| 7.4L | ||||
| Oxygen Sensor Signal | A10 | Purple | ||
| Oxygen Sensor Ground | A12 | Tan | ||
| "G" Series | ||||
| 7.4L A/T | ||||
| Oxygen Sensor Signal | A10 | Purple | ||
| Oxygen Sensor Ground | A12 | Tan | ||
| "P" Series | ||||
| 7.4L A/T | ||||
| Oxygen Sensor Signal | A10 | Purple | ||
| Oxygen Sensor Ground | A12 | Tan | ||
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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.