1500 4x2 Pickup V8-5.2L CNG VIN T (1996)
Fluid Pressure Sensor/Switch: All Technical Service Bulletins
A/T - Engine Bucking/Surging at 5,300 Rpm
NO: 18-19-98
GROUP: Driveability
DATE: Apr. 10, 1998
SUBJECT:
Vehicle Bucking During Wide Open Throttle Acceleration
MODELS:
1996 - 1998
(AB)
Ram Van
1996 - 1998
(AN)
Dakota
1996 - 1998
(BR/BE) Ram Truck
1998
(DN)
Durango
1996 - 1998
(ZJ)
Grand Cherokee
1996 - 1998
(ZG)
Grand Cherokee (International Markets)
NOTE:
THIS INFORMATION APPLIES TO VEHICLES BUILT BEFORE JAN 16, 1998 MDH (0116XX) EQUIPPED WITH GASOLINE ENGINES
AND A 42/44/46 OR 47RE TRANSMISSION.
SYMPTOM/CONDITION:
Some vehicles may experience bucking during wide open throttle (WOT) acceleration. The bucking occurs at approximately 5300 RPM. This condition
may be caused by reaching the high RPM fuel shut off rev limit before the transmission can shift into the next higher gear and is most likely to occur
with high electrical loads (high beams on, heated back lite, heated seats, radio, HVAC blower on MAX etc.). During high current demands, the generator
may emit electrical noise that can affect the transmission governor pressure sensor output. If this occurs, the transmission may not shift properly to the
next higher gear under (WOT) acceleration conditions and therefore reach the fuel shut off rev limiter. This may be seen most often between the 2-3 shift
but can also be experienced between the 1-2 shift.
DIAGNOSIS:
Using the Diagnostic Scan Tool (DRB III(R)) with the appropriate Diagnostic Procedures Manual, verify all engine/transmission systems are functioning
as designed. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order and repair as necessary before proceeding further with this
bulletin.
NOTE:
ONLY PERFORM THE FOLLOWING PROCEDURE SAFELY ON A HIGHWAY OR ROAD OBEYING ALL POSTED SPEED LIMITS AND
LAWS.
Attempt to duplicate the condition by switching on all accessory loads and driving the vehicle with WOT accelerations through a shift sequence to see if
the engine will reach the fuel shut off rev limiter before the 2-3 or 1-2 shift is made.
If the bucking condition is experienced at approximately 5300 RPM before making the appropriate upshifts, switch off all electrical loads and repeat the
procedure. Repeat the procedure with the electrical loads on and off a second time. If the bucking occurs with the electrical loads on and does not occur
with the loads off, perform the Repair Procedure.
PARTS REQUIRED:
1
56041403AA
Sensor, Governor Pressure
REPAIR PROCEDURE:
This bulletin involves installing a newly designed governor pressure sensor.