P1653

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION
The EGR flow is controlled by the vacuum actuated EGR valve. The EGR vent solenoid purges to atmosphere the vacuum level at the EGR valve actuator as commanded by the Powertrain Control Module (PCM). This is done when the EGR flow is desired to turn off quickly. When the PCM is commanding the EGR vent ON, the voltage potential of the circuit will be low (near 0 volts). When the PCM is commanding the EGR vent OFF, the voltage potential of the circuit will be high (near battery volts). The primary function of the PCM in this circuit is to supply the ground for the EGR vent solenoid. This is a type B code.

CONDITIONS FOR SETTING THE DTC
- PCM requested EGR vent ON.
- Voltage on EGR vent control circuit high (near battery volts).
- Conditions met for 2 seconds. or
- PCM requested EGR vent solenoid OFF.
- Voltage on EGR vent control circuit low (near 0 volts).
- Conditions met for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- No EGR.
- Possible black smoke on acceleration.

CONDITIONS FOR CLEARING THE MIL/DTC
- The PCM will turn the MIL off after three consecutive trips without a fault condition.
- A History DTC will clear when forty consecutive warm-up cycles that the diagnostic does not fail (coolant temperature has risen 5°C (40°F) from start up coolant temperature and engine coolant temperature exceeds 71°C (160°F) that same ignition cycle.

DIAGNOSTIC AIDS
The scan tool has a 5 second ON time abort. The EGR vent solenoid can be commanded ON for as many times as needed, in 5 second intervals. Its possible other EGR DTCs may set along with DTC P1653. This diagnostic can be checked at key up. A quick operational check can be made by commanding the EGR vent solenoid ON and OFF with the scan tool while monitoring Actual EGR. Actual EGR will display Barometric Absolute Pressure (BARO) (approximately) when EGR solenoid is OFF.

TEST DESCRIPTION
Number(s) below refer to the Step number(s) on the Diagnostic Table.

2. Be sure that both the ON and OFF states are commanded. Repeat the commands as many times as necessary.
3. This check can detect a partially shorted coil which would cause excessive current flow. Leaving the circuit energized for 2 minutes allows the coil to warm up. When warm, the coil may open (Amps drop to zero, or short (Amp draw greater than 0.75 A).
7. Listen for an audible click when the solenoid operates.