P1561

DTC P1561 Cruise Vent Solenoid Circuit Diagnostic Chart:

Cruise Control Servo Wiring Schematic:

CIRCUIT DESCRIPTION
The cruise switch within the turn signal lever receives ignition voltage from a 15 amp fuse through CKT 639 to the turn signal lever-cruise switches. The cruise "ON/OFF" "SET/COAST," and "RESUME/ACCEL" switches are inputs to the cruise control portion of the Powertrain Control Module (PCM).

The cruise servo vent and vacuum solenoid outputs are controlled by high side drivers in the PCM. When the ignition is "ON" the PCM looks at these output lines and will set Diagnostic Trouble Codes (DTCs) if an incorrect status is seen on any line.

The vent solenoid is a normally open (de-energized) solenoid valve that allows any vacuum in the cruise servo to be depleted. When the solenoid is energized ("ON"), the cruise servo holds vacuum allowing the servo to stay retracted and hold open the throttle.

DTC P1561 WILL SET WHEN
^ CKT 403 is shorted to voltage when the vent solenoid is commanded "OFF."
^ CKT 403 is open.
^ CKT 403 is shorted to ground when the PCM is commanding the vent solenoid "ON."
^ One of the above conditions are met for more than a half of a second.

ACTION TAKEN (PCM WILL DEFAULT TO)
The PCM will not allow cruise control operation with a current DTC P1561 set. DTC P1561 does not illuminate the Malfunction Indicator Lamp (MIL).

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation.

Check for:
^ Poor connection or damaged harness - Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.