Dakota 4WD V8-318 5.2L Magnum (1995)
Powertrain Control Module: Customer Interest
PCM - Cold Start Sag/Hesitation or Backfire/Pop
NO: 18-23-95
GROUP: Vehicle Performance
DATE: Jun. 30, 1995
SUBJECT:
Cold Start Sag/Hesitation and/or Exhaust Backfire or Pop
MODELS:
1994 - 1995
(AB) Ram Van/Wagon
1994 - 1995
(AN) Dakota
1994 - 1995
(BR) Ram Truck
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A 3.9L ENGINE.
SYMPTOM/CONDITION:
^
Driving away after a cold start up, a sag/hesitation may be experienced. At idle, a slight engine surge/rough idle may also be felt. The condition may
persist for up to one minute and be most prevalent on cold starts at ambient of 60-80 degrees F.
^
An exhaust backfire or popping noise in the exhaust system may occur during a closed throttle deceleration before the engine has reached normal
operating temperatures.
^
The vehicle may exhibit one or both of these conditions.
DIAGNOSIS:
Using the Mopar Diagnostic System (MDS) or Scan Tool (DRB III) with the appropriate Diagnostic Procedure Manual, verify that all
engine/transmission systems are functioning as designed. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order and repair
before proceeding with the repair procedure in this bulletin.
COLD START SAG/HESITATION:
1.
Allow engine to cool down at least eight (8) hours, preferably overnight.
2.
Following cold start drive away, make frequent stops and medium accelerations checking for sags and hesitations. If sags or hesitations result,
perform the repair procedure.
EXHAUST BACKFIRE OR POPPING NOISE:
1.
While vehicle is still cold, start engine and accelerate in first gear until engine speed reaches 3000 RPM.
2.
Remove foot from accelerator pedal. Decelerate the vehicle and allow the vehicle to come to a stop.
3.
If a backfire or popping sound comes from the exhaust system during deceleration, perform the repair procedure.
PARTS REQUIRED:
1
4798341
POM, 3.9L Man. Trans AN Body 1994 MY
1
4798342
POM, 3.9L Auto Trans. AN Body 1994 MY
1
4798343
POM, 3.9L Auto Trans. AB Body 1994 MY
1
4798344
POM, 3.9L Man. Trans. BR Body 1994 MY
1
4798345
PCM, 3.9L Auto Trans. BR Body 1994 MY
1
4275086
Label - Authorized Modification
1
4669020
Label - Authorized Software Update
EQUIPMENT NEEDED:
1
CH6OOO
Scan Tool (DRB III)
1
CH7035
General Purpose Interface Bus Cable (GPIB)
1
CH7015
Engine Cable
REPAIR PROCEDURE:
This bulletin includes the replacement of the Powertrain Control Module (PCM) for 1994 model year vehicles, and the flashing of 1995 model year
vehicles with revised software.
MODULE REPLACEMENT:
This section of the bulletin involves the replacement of the powertrain control module with one of the above powertrain control modules.