EGR System Test
- To check system operation, place transaxle in Park (A/T) or Neutral (M/T). Apply parking brake.
- With coolant temperature less than 104°F (40°C), start engine and operate at high RPM. EGR valve diaphragm should not retract.
- Allow engine to reach normal operating temperature. Operate engine at high RPM. EGR valve diaphragm should retract and return to normal idle on deceleration.
- If EGR valve does not operate as specified, check for misrouted, restricted, clogged or deteriorated vacuum hoses. If vacuum hoses are okay, check EGR valve. See EGR VALVE below. If EGR valve is okay, check EGR pressure transducer. See EGR PRESSURE TRANSDUCER below. If EGR pressure transducer is okay, go to next step.
- Check EGR solenoid vacuum valve, EGR system check valve, related components and PCM. See DTC P0400 in BASIC TESTING article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate TESTS W/CODES article.