SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET1987STEP VAN P20, 7.4 W, AUTOMATIC, 400/M40REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 16 (ENGINE CONTROLS - TESTS W/CODES - 5.7L)TROUBLE CODE CHARTSCODE 31, ENGINE SPEED GOVERNOR - 5.7L "G" SERIESNOTES
1987 Chevrolet Step Van P20, 7.4 W, Automatic, 400/M40

Code 31, Engine Speed Governor - 5.7L "G" Series: Notes

1987 Chevrolet Step Van P20, 7.4 W, Automatic, 400/M40SECTION Notes
WARNING: This page does not describe the selected car, but rather 20 other vehicles, including the 1994 GMC Yukon, 1994 GMC Vandura Special, 1994 GMC Vandura, 1994 GMC Suburban, and 1994 GMC Rally Camper Special. However, it is still accessible from the selected car via links, so may be relevant.

The PCM controls the engine speed control governor based upon engine speed (RPM). The PCM sends a pulse width modulation signal to the engine speed control governor module to drive the engine speed control governor motor. Depending upon the amount of governing required, the module translates the PCM data into a voltage signal which it sends to the motor. The motor then pulls back the throttle to the correct overspeed condition.

A Code 31 will set if a fault occurs in the governor module, motor, linkage, wiring or PCM. If Code 31 is set, the PCM will limit engine speed by momentarily reducing fuel delivery to injectors.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. Determines if engine speed governor module has proper voltage.
  2. Applying voltage to the motor will determine motor, wiring and linkage integrity. DO NOT  hold current to motor for longer than 30 seconds or damage to motor will result.
  3. This will command full governing to determine if PCM or engine speed governor is at fault.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready ToolsFree Quote CheckQuote Shield Pro

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.