LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 1982 >> Magnavan Automatic Trans, Trans Mfr CD 475/M40 >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 1 (EGR Function Testing - General Motors Trucks) >> EGR Function Testing - General Motors Trucks >> Test 3

Test 3

WARNING: This page is about a different variant/trim than selected.
  1. Install scan tool. Ensure transmission range switch is operating properly. With engine at normal operating temperature, command EGR pintle position to zero percent. Increase engine speed to 2000 RPM. If scan tool reads actual EGR pintle position at greater than 3 percent, EGR valve is stuck open. Replace EGR valve.
  2. If scan tool reads actual EGR pintle position at 3 percent or less, command a 25 percent position step increase (i.e. 0-25 percent, 25-50 percent, 50-75 percent, etc.). Observe MAP reading and actual EGR pintle position for 3 seconds. EGR should increase by about 25 percent position and MAP reading should also increase.
  3. If actual EGR pintle position is stable and within 10 percent of desired EGR pintle position command after 2 seconds, go to next step. If actual EGR pintle position is not as specified, go to step 5).
  4. MAP reading should have increased when EGR pintle responded. If MAP did not respond, check EGR passages and EGR valve for blockage. If MAP responded, set desired EGR pintle position to 100 percent. If EGR pintle position sets to 100 percent, EGR is okay. If not, replace EGR valve.
  5. Turn engine off. Check EGR electrical circuit and connecting components. Turn ignition on, check for 5-volt reference voltage on harness connector terminal "D" (Gray wire). If 5-volt reference voltage is not present, check PCM/VCM. If circuits are okay, replace EGR valve.
scientia non olet · About LEMON Manuals