Symptom Diagnosis Test
- If engine stalls on decel, or at idle, proceed to step 1).
- If engine has high idle speeds on every restart, proceed to step 2).
- If incorrect or incomplete service codes are displayed, perform Diagnostic Circuit Test.
- If drive complaints are intermittent, perform Continuous Testing portion of Quick Test.
- If engine stalls, runs rough or misses, check electrical connections, ignition system. If no problems are found, proceed to step 4). After completing test, perform No Start Test.
- Disconnect and plug vacuum hose from EGR valve. Start and run engine until it reaches normal operating temperature. Perform Quick Test. If vehicle does not stall, EGR service is required. If vehicle stalls, perform Idle Speed Control Test.
- Turn ignition key off. Connect voltmeter negative lead to self test output wire and positive lead to battery positive terminal. DO NOT connect grounded jumper to self test input wire. Turn ignition key on and observe voltmeter. If no pulsing codes are displayed, perform Idle Speed Control Test. If pulsing codes are displayed, proceed to step 3).
- Disconnect ECA connector J1. Measure resistance from ECA connector J1 pin 13 to chassis ground. If resistance is less than 10,000 ohms, repair short to ground in White/Red wire leading from pin 13 to self test input connector. If resistance is 10,000 ohms or above, disconnect and inspect ECA connectors for damaged or corroded terminals. If connectors are good and fault is still present, replace ECA.
- Disconnect and plug all vacuum lines connected to EGR on off solenoid. Connect a hand-held vacuum pump to lower port on solenoid. Start and run engine until it reaches normal operation temperature. Let engine idle for 3 minutes, then apply 10 in. Hg vacuum to solenoid using vacuum pump.
- Vacuum should hold. While observing vacuum gauge, rapidly accelerate engine. Vacuum should bleed off. If vacuum holds at idle and bleeds off during acceleration, EEC system is okay. Check EGR valve and Backpressure Variable Transducer Valve. If vacuum does not hold, proceed to step 6). If vacuum does not bleed off, proceed to step 7).
- Disconnect harness from EGR solenoid. apply 10 in. Hg vacuum to solenoid. If solenoid does not hold vacuum, replace solenoid. If solenoid holds vacuum, check circuit from ECA connector J2 pin 17 for shorts to ground. If okay, disconnect and inspect ECA connectors for damaged or corroded terminals. If connectors are good, reconnect ECA and retest. If problem is still present, replace ECA.
- Turn ignition key off and disconnect wiring harness from EGR solenoid. Measure resistance of EGR solenoid coil. If resistance is not within 45-90 ohms, replace solenoid. If resistance is within 45-90 ohms, proceed to step 8).
- With ignition key on, solenoid and ECA connected, measure voltage at Yellow wire at EGR connector. If voltage is less than 10.5 volts, repair poor connection or open circuit in Red wire connected to solenoid. If voltage is more than 10.5 volts, check Yellow wire connected to solenoid for opens. If okay, disconnect and inspect ECA connectors for damaged or corroded terminals. If okay, reconnect ECA and retest. If problem is still present, replace ECA.