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.
1991 Chevrolet APVFACTORY OEM SERVICE PROCEDURE
Engine Controls - Pin Voltage Charts
- Introduction
- ECM Terminal Id & Pin Voltages
- 2.5L "S" Series Truck
- 2.8L "S" Series Truck
- 4.3L "S" & "T" Series Truck & "M" & "L" Series Van
- 4.3L & 5.7L "G" Series Van
- 4.3L, 5.0L & 5.7L "C" & "K" Series Van W/O 4L80-E A/T
- 5.7L & 7.4L "R" & "V" Series W/O 4L80-E A/T
- 4.3L, 5.7L & 7.4L "C", "K", "R" & "V" Series W/4L80-E A/T
- 6.2L Diesel "R" & "V" Series W/4L80-E A/T
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.