Circuit Description

VCM tests exhaust gas recirculation valve by momentarily commanding valve on while monitoring manifold absolute pressure. If expected manifold absolute pressure increase is not seen under certain operating conditions (decel) for a calibrated number of tests, VCM will turn on Malfunction Indicator Light (MIL) and store DTC P0401.

Conditions for setting DTC:

• No ECT, IAC, IAT, MAP, TP, VSS sensor DTCs are set.
• No linear EGR pintle position DTCs are set.
• No transmission DTCs set.
• ECT is greater than 154°F (70°C).
• BARO is greater than 70 kPa (less than 10,3000 ft.).
• Vehicle speed is greater than 25 MPH.
• A/C clutch status is unchanged.
• Transmission status is unchanged.
• No misfire DTCs are set.
• Engine speed is 1000-1600 RPM.