Circuit Description

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

Conditions required to set DTC are:

• No ECT, EVAP, IAC, IAT, MAP, TP or VSS DTCs set.
• BARO is greater than 72 kPa.
• ECT is greater than 140°F (60°C).
• IAC position is steady, changing less than 5 counts.
• System voltage is 11.5-16 volts.
• Vehicle speed greater than 14 MPH.
• A/C clutch status is unchanged.