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Home >> GMC >> 1987 >> Forward Control 6.2 J, Automatic, 475/M40 >> Repair and Diagnosis >> Engine Performance >> System >> CCC TBI Tests W/Codes >> Diagnostic Charts >> Code 32 - EGR System Failure (2.8L) >> Test Description

Test Description

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. Code 32 means that EGR vacuum switch was closed during start-up or that vacuum switch was not detected closed under the following conditions:
    • Coolant temperature above 185°F (85°C).
    • EGR duty cycle commanded by ECM is greater than 70%.
    • TPS less than half throttle, but not at idle.
    • All above conditions must be present for 5 seconds. If vacuum switch is detected closed during start-up or, if switch is detected open when the above conditions are met, the "SERVICE ENGINE SOON" light will remain on unless the vacuum switch changes position.
  2. If step 1) caused Code 32 to set, then the ECM has recognized a closed vacuum switch on start-up. This step will determine whether the EGR control valve is the cause, or if the wiring or ECM is the cause.
  3. With ignition on, solenoid should not be energized and vacuum should not flow to EGR valve.
  4. The EGR solenoid and valve are okay and the next step will check the vacuum switch portion of the system.
  5. The switch should close at about 2 in. Hg. With vacuum applied, the switch should close and resistance should be near zero ohms and vacuum should hold.