P0221

Diagnostic Chart (Part 1 Of 2):

Diagnostic Chart (Part 2 Of 2):

Schematic:

CIRCUIT DESCRIPTION
The Accelerator Pedal Position (APP) module provides a voltage signal that changes relative to the accelerator position. There are 3 differently scaled sensors located within the APP module.

CONDITIONS FOR RUNNING THE DTC
^ The ignition voltage is more than 6.4 volts.
^ The engine speed is more than 300 RPM.
^ There are no in range faults for APP 1 or APP 3. The Powertrain Control Module (PCM) checks for high and low voltage faults.

CONDITIONS FOR SETTING THE DTC
^ The difference between APP 2 and APP 3 is more than 0.50 volts. The PCM compares pre-scaled voltage that is internal to the PCM.
^ The difference between APP 2 and APP 1 is more than 0.23 volts. The PCM compares the pre-scaled voltage that is internal to the PCM.
^ The conditions were met for 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The service throttle soon lamp will not illuminate when one APP DTC sets. The PCM will only illuminate the service throttle soon lamp when multiple APP DTCs set.
^ The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the DTCs.

DIAGNOSTIC AIDS
There are no driveability issues associated with the APP module unless a DTC is present. The most likely causes of this DTC are faulty connections or the sensor itself. The least likely cause is a Powertrain Control Module (PCM) problem.

An intermittent may be caused by:
^ Faulty connections
^ Rubbed-through wire insulation
^ Broken wire inside the insulation

A scan tool reads the APP 2 position in volts and should read approximately 4.5 volts with the throttle closed and the ignition ON or at idle. The voltage should steadily decrease as the throttle is moved toward Wide Open Throttle (WOT). Also, 90 percent pedal travel is acceptable for correct APP operation. Scan the APP 2 sensor while depressing the accelerator pedal with the engine stopped and the ignition ON. The display should vary from approximately 4.5 volts when the throttle is closed to approximately 1.5 volts when the throttle is held at the WOT position.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
4. This step determines if there is a good 5-volt reference.
5. This step will check for an open in the ground circuit.