Code 53 - EGR Control Error (3.8L)
Code 53 will be set if EGR diagnostic switch senses vacuum when ECM signals no EGR or senses no vacuum when ECM signals for EGR. The EGR solenoid is energized based on the engine running above idle but less than WOT, engine coolant temperature at least 108°F (42.5°C) and transmission in gear. The "pulse width" for EGR solenoid is determined by engine load input to ECM.
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- This tests for a stuck vacuum switch or grounded wire to ECM diagnostic switch input. Normally no code would be set at idle.
- Load the engine in Drive to check if diagnostic switch senses EGR which is under normal load. If the "SERVICE ENGINE SOON" light comes on, a fault is present.
- This test checks if circuit 345 is grounded to EGR solenoid. Normally light should be off.
- This test checks if circuit 345 to EGR solenoid is open. By grounding diagnostic test terminal, test light should be on if ECM is functioning and solenoid wiring is okay.
- This tests circuits 432 and 450 from ECM to diagnostic vacuum switch. Normally a voltmeter will read battery voltage if circuits are okay.
- This test determines whether diagnostic switch or EGR solenoid is faulty. By applying 10 in. Hg vacuum to diagnostic switch with an ohmmeter across terminals of switch, a functional check can be made. If the switch functions and resistance drops to near zero, fault is a poor connection or faulty solenoid.