Circuit Description

PCM tests Exhaust Gas Recirculation (EGR) valve during deceleration by momentarily commanding EGR valve on while monitoring engine MAP. PCM will illuminate MIL and store DTC P0401 if expected increase in MAP is not seen under test conditions during deceleration.

Conditions required to set DTC are:

• No CKP, ECT, EGR pintle position, IAT, MAP, or TP sensor DTCs set.
• No misfire or VSS DTCs set.
• BARO is greater than 75 kPa.
• ECT greater than 140°F (60°C).
• IAC position steady, changing less than 10 counts.
• System voltage is 11.5-16 volts.
• Vehicle speed greater than 15 MPH.
• Commanded state of A/C relay is steady.