LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 1994 >> Forward Control 7.4 N >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 6.5L Diesel >> Diagnostic Trouble Code Charts >> DTC 71 - Set/Coast Switch Fault >> Notes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC 71 - Set/Coast Switch Fault: Notes

The cruise ON/OFF, SET/COAST and RESUME/ACCEL switches are inputs to the fuel control portion of the PCM. These inputs allow the PCM to control and hold a requested speed. The set/coast request signal circuit supplies ignition voltage to the PCM when set/coast is depressed. DTC 71 will set when:

PCM will default to the PCM disallowing all cruise inputs. TCC shift schedules may be affected.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. This step determines if the cruise control switch is okay.
  2. This step determines if the PCM or switch is at fault.