DaimlerChrysler Jeep Grand Cherokee 2002, Service Manual

Page: 169 / 284

Symptom:
P0850-P/N SWITCH PLAUSIBILITY
When Monitored and Set Condition:
P0850-P/N SWITCH PLAUSIBILITY
When Monitored: With the engine running at >3700 RPM, accelerator pedal position
sensor >70%, fuel quantity >60 mm
3
, and the transmission physically not in Park or
Neutral.
Set Condition: The ECM receives a P/N Switch input of Neutral or Park.
POSSIBLE CAUSES
CHECKING THE P/N SENSE CIRCUIT
ENGINE CONTROL MODULE
P/N SENSE CIRCUIT SHORTED TO VOLTAGE
P/N SWITCH SENSE CIRCUIT OPEN
P/N SWITCH SENSE CIRCUIT SHORTED TO GROUND
INTERMITTENT CONDITION
TEST ACTION APPLICABILITY
1 With the DRBIII
t
, record and erase DTCs.
Test drive the vehicle.
With the DRBIII
t
, read the ECM DTCs.
Does the DRBIII
t
display this DTC?
All
Yes
→
Go To 2
No
→
Go To 6
2 Turn the ignition off.
Disconnect the TCM harness connector.
Turn the ignition on.
With the DRBIII
t
in Engine Inputs/Outputs, read the P/N Switch state.
Connect one end of a jumper wire to the P/N Switch Sense circuit at the TCM harness
connector. Connect the other end of the jumper to ground for 10 seconds then
disconnect from ground.
Dose the DRB Switch state change when connecting and disconnecting from ground?
All
Yes
→
The Park/Neutral Position Sense circuitry is operating properly.
Refer to Transmission Diagnostic information for the related
symptom(s).
Perform ROAD TEST VERIFICATION - VER-2.
No
→
Go To 3
161
DRIVEABILITY - DIESEL
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