Codes P1403/P1404/P1405, EGR Error: Notes

Codes P1403, P1404 and P1405 are EGR flow test failures. PCM tests medium and large EGR solenoid valves by cycling each of them on momentarily while monitoring engine RPM. When a solenoid is on, PCM expects to see a drop in engine RPM. Codes P1403, P1404 and P1405 will set when the following conditions are present.

• Engine coolant temperature is greater than 183°F (84°C).
• Vehicle is in coast down condition.
• Vehicle not in decel fuel cutoff.
• Heated oxygen sensor voltage greater than .57 volt.
• Vehicle in 1st or 2nd gear.
• Vehicle speed is greater than 20 MPH.
• A/C clutch not engaged.
• RPM 925-1063 (to run EGR No. 1 test).
• RPM 975-1188 (to run EGR No. 2 test).
• RPM 1000-1488 (to run EGR No. 3 test).
  NOTE: Test numbers refer to numbers on diagnostic chart.

1. A change in engine RPM should be detected as each solenoid is cycled on.
2. If test light lights, PCM and wiring are okay.