DaimlerChrysler Jeep Grand Cherokee 2002, Service Manual

Page: 215 / 284

POSSIBLE CAUSES
VERIFY APP SENSOR OPERATION
APP SENSOR SIGNAL CIRCUIT SHORTED TO THE SENSOR GROUND CIRCUIT
5-VOLT SUPPLY OR SENSOR REF VOLTAGE A CIRCUIT SHORTED TO VOLTAGE
ECM - SENSOR GROUND OPEN
APP SENSOR CIRCUIT SHORTED TO VOLTAGE
APP SENSOR GROUND CIRCUIT SHORTED TO VOLTAGE
ECM - APP SENSOR SIGNAL CIRCUIT
TEST ACTION APPLICABILITY
1 NOTE: If DTC P0641 or P0651 is present with this DTC, diagnose DTCs
P0641 and P0651 before diagnosing this DTC.
NOTE: The APP Sensor is a device that contains 2 separate potentiometer
type sensors. Each sensor has its own 5-volt supply circuit, sensor ground
circuit and signal circuit. The APP Sensor no longer incorporates a low-idle
switch.
NOTE: The APP Sensor #2 signal should always be 1/2 the voltage of the APP
Sensor #1 signal.
Turn the ignition on.
With the DRB, read the APP Sensor #1 and APP Sensor #2 Volts with the accelerator
pedal in the at rest position.
Does the DRB display between 0.50 and 0.90 volt for sensor #1 and 1/2 the #1 voltage
for #2? All
Yes
→
Go To 2
No
→
Go To 5
2 Turn the ignition on.
Fully depress the accelerator pedal.
With the DRB, read the voltage for APP Sensor #1 and APP Sensor #2.
Does the DRB display between 4.0 and 4.5 volts for #1 and 1/2 #1 voltage for #2? All
Yes
→
Go To 3
No
→
Go To 5
3 Turn the ignition on.
With the DRB, read the APP Sensor #1 and APP Sensor #2 percentages (%).
With the accelerator pedal in the idle position, slowly depress the accelerator pedal
until the pedal is fully depressed.
NOTE: The percentage readings for APP Sensor #1 and #2 should increase
smoothly as the pedal is depressed.
Does the percentage increase smoothly for both readings with the accelerator pedal
travel? All
Yes
→
Go To 4
No
→
Replace the Accelerator Pedal Position Sensor in accordance with
the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
207
DRIVEABILITY - DIESEL
P2120-ACC PEDAL POSITION SENSOR 1 CKT PLAUSIBILITY —
Continued
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