RAM 1500 Truck 2WD V6-3.9L VIN X (1999)
PROM - Programmable Read Only Memory: Customer Interest
PCM - Start and Stall, Idle Undershoot/Lost IAC Steps
NO: 18-36-98
GROUP: Vehicle Performance
DATE: Dec. 18, 1998
SUBJECT:
Start And Stall, Idle
Undershoot - Lost
Idle Air Control (IAC) Steps
MODELS:
1999
(AB)
Ram Van
1999
(AN)
Dakota
1999
(BR/BE)
Ram Truck
1999
(DN)
Durango
1999
(TJ)
Wrangler
1999
(WJ)
Grand Cherokee
1999
(XJ)
Cherokee
NOTE:
THIS INFORMATION APPLIES TO VEHICLES EQUIPPED WITH GASOLINE ENGINES BUILT PRIOR TO DEC. 18, 1998 (MDH 1218XX).
SYMPTOM/CONDITION:
Some vehicles may exhibit an idle undershoot or die out during engine starting and may be caused by IAC lost steps. This condition is more likely to
occur during cold weather, low battery voltage, cold engine start, and quick ignition key "On" - "Off" operation.
DIAGNOSIS:
Using the Mopar Diagnostic System (MDS/MDS2) or 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. If no other problems are found, perform the Repair.
NOTE:
WHENEVER A POWERTRAIN CONTROL MODULE (PCM) IS REPLACED DUE TO FAILURE, THE SOFTWARE OF THE
REPLACEMENT CONTROLLER SHOULD BE VERIFIED FOR THE LATEST REVISION LEVEL. USE THE FLASH PROCEDURE TO
UPDATE REPLACED CONTROLLERS AS NECESSARY.
EQUIPMENT/PARTS REQUIRED:
1
CH6000
Scan Tool (DRB III(R))
1
CH7035
General Purpose Interface Bus Cable (GPIB)
1
CH7000/7001
J1962 Cable
1
04669020
Label - Authorized Software Update
1
04275086
Label - Authorized Modification
NOTE:
THE MDS AND DRB III(R) ARE REQUIRED TO PERFORM THIS REPAIR AND THE SYSTEM MUST BE OPERATING WITH RELEASE
21 OR HIGHER AND TIL CD RELEASE 1175 OR HIGHER MUST BE INSTALLED.
REPAIR PROCEDURE:
This procedure involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software (99cal14 calibration change).
1.
Connect the MDS (Mopar Diagnostic System) and DRB III(R) (Scan Tool) to the vehicle and power them up.
2.
Use the arrow keys and select # 2 CONNECT TO MDS 1 OR MDS 2 on the DRB III(R) MAIN MENU Screen.
3.
Select # 1 MDS DIAGNOSTICS OR DRB UPDATE on the DRB III(R).
4.
Use the arrow keys and select DIAGNOSTIC MENU on the MDS, then press NEXT MENU.