Diagnostic Aids

Check for poor harness connections or harness damage. If no problems are found, turn ignition on. Backprobe applicable PCM terminals with a DVOM while wiggling harness. If a failure is induced, voltage reading will change. If no problems are found, check EGR valve pintles and orifices for excessive carbon build-up. Also, check for plugged EGR tube or passages.

Fig 1: CODE 53-55, Schematic, EGR Fault (3.8L)

Fig 2: CODE 53-55, Flowchart, EGR Fault (3.8L)