DTC P1491: EGR Valve Insufficient Lift 1. Reset the ECM/PCM. 2. Start the engine. Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on. 3. Check for a Temporary DTC with the scan tool. 4. Test-drive the vehicle for approx. 10 minutes. Try to keep the engine speed in the 1,700-2,500 rpm range. Is Temporary DTC P1491 indicated? YES – Go to step 5. NO – 5. Turn the ignition switch OFF. 6. Disconnect the EGR valve 6P connector. 7. Start the engine and let it idle.
8. Measure voltage between EGR valve 6P connector terminals No. 4 and No. 6. Is there battery voltage? YES – Substitute a known-good ECM/PCM and recheck. If the symptom/indication goes away, replace the original ECM/PCM. NO – Go to step 9. Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the EGR valve and the ECM/PCM. 9. Turn the ignition switch OFF. 10. Turn the ignition switch ON (II). 11. Measure voltage between EGR valve 6P connector terminals No. 2 and No. 3. Is there approx. 5 V?Related Entry : p1491 honda accord 2000, honda accord 2000 egr insufficient air p1491, honda accord 2000 ex p1491dp, 2000 honda accord code p1491, 2000 honda accord p1491 code, p1491 honda, p1491 pd honda,