Test W - EGR On-Off Check
NOTE:
Code 34 may be result of high volume exhaust vent system reducing backpressure. If this is suspected, perform test in well-ventilated area without exhaust vent connected.
- Code 34 Displayed. Use only VOM/DVOM, not STAR tester, for this step. Turn key OFF and wait 10 seconds. Place DVOM on 20 volt scale. Connect negative DVOM lead to STO and positive lead to positive battery terminal. Insert jumper wire between STI and signal return circuit to enter Output State mode. Perform KOEO Self-Test until end of Continuous Test Code display. DVOM will read 0 volts. Depress and release throttle and observe DVOM reading. If DVOM did not show high voltage, depress throttle to WOT and release. If output voltage does not go to high reading, go to Circuit Test NN, step 13). If DVOM registered high reading, stay in Output State mode and go to next step of this test. Leave equipment connected.
- Set DVOM to 20 volt scale. Connect DVOM positive lead to VPWR at EGR solenoid and negative lead to EGR output circuit. Depress and release throttle several times while observing DVOM. EGR output should cycle ON and OFF as throttle is operated. If so, go to next step. If not, remove signal return jumper wire and go to step 5) of this test.
- Disconnect DVOM and leave jumper wire installed. Connect vacuum pump to solenoid vacuum supply port and vacuum gauge to output port of solenoid. Apply minimum vacuum of 6 in. Hg. Depress and release throttle several times to cycle EGR output while maintaining vacuum at supply port. Note vacuum gauge reading. If vacuum output cycles, go to next step. If vacuum output does not cycle, replace EGR solenoid and repeat QUICK TEST.
- Remove jumper wire, vacuum gauge and vacuum pump. With vacuum lines disconnected at EGR solenoid, start engine. If vacuum is present, EEC-IV system is not cause of problem. Check EGR system. If vacuum is not present, correct vacuum source blockage or leak and repeat QUICK TEST.
- Turn key OFF and wait 10 seconds. Leave EGR solenoid disconnected. Set DVOM on 200 ohm scale. Measure solenoid resistance. If resistance is less than 65 ohms or more than 110 ohms, replace solenoid and repeat QUICK TEST. If resistance is between 65-110 ohms, reconnect solenoid and go to next step.
- Turn key ON, leaving engine OFF. Set DVOM to 20 volt scale. Measure voltage at EGR solenoid connector between VPWR and ground. If less than 10.5 volts, repair open in harness and repeat QUICK TEST. If 10.5 volts or higher, go to next step.
- Turn key OFF and wait 10 seconds. Disconnect 60-pin ECA connector. Inspect for and repair any damaged wiring. Connect breakout box and leave ECA disconnected. Set DVOM to 200 ohm scale. Measure resistance between test pin 35 and EGR circuit at connector. If 5 ohms or higher, repair open circuit and repeat QUICK TEST. If less than 5 ohms, go to next step.
- Turn key OFF and wait 10 seconds. Place DVOM on 200,000 ohm scale. Leave breakout box installed and ECA disconnected. Disconnect EGR solenoid. Measure resistance between test pin 35 and test pins 40, 46, and 60. If 10,000 ohms or more, go to next step. If less than 10,000 ohms, repair short to ground and repeat QUICK TEST.
- Turn key OFF and wait 10 seconds. Leave breakout box installed with ECA and EGR solenoid disconnected. With DVOM on 200,000 ohm scale, measure resistance between test pin 35 and test pins 37 and 57. If less than 10,000 ohms, repair short to power and repeat QUICK TEST. If 10,000 ohms or more, replace ECA and repeat QUICK TEST.