RE: Popping while Engine Braking

From: Thomas Mize (dakotasport94@hotmail.com)
Date: Tue Nov 09 2004 - 16:41:30 EST


TSB 18-23-95

NO: 18-23-95
SUBJECT: Cold Start Sag/Hesitation and/or Exhaust Backfire or Pop
DATE: Jun. 30, 1995
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:

Allow engine to cool down at least eight (8) hours, preferably overnight.
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:

While vehicle is still cold, start engine and accelerate in first gear until
engine speed reaches 3000 RPM.
Remove foot from accelerator pedal. Decelerate the vehicle and allow the
vehicle to come to a stop.
If a backfire or popping sound comes from the exhaust system during
deceleration, perform the repair procedure.
PARTS REQUIRED:
Quantity
Part No.
Description

1

4798341
PCM, 3.9L Man. Trans AN Body 1994 MY

1

4798342
PCM, 3.9L Auto Trans. AN Body 1994 MY

1

4798343
PCM, 3.9L Auto Trans. AB Body 1994 MY

1

4798344
PCM, 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:

Quantity
Part No.
Description

1

CH6000
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.

Record all radio station presets.
Disconnect negative cable at battery and isolate.
Remove 60 way electrical connector from PCM (one bolt). PCM is located in
the right rear side of the engine compartment.
Remove the three PCM mounting bolts and remove PCM.
Install new PCM and torque bolts to 9 in. lbs. (1 Nm) torque.
Connect 60 way electrical connector to PCM. Torque bolt to 35 in. lbs. (4
Nm).
Connect negative cable to battery.
Program radio station presets and clock.
Proceed to module reprogramming.
1995 MODULE REPROGRAMMING:

This section of the bulletin involves reprogramming the PCM with new
software and installation of appropriate labels.

NOTE: THE MOPAR DIAGNOSTIC SYSTEM IS REQUIRED TO PERFORM THE FOLLOWING
REPAIR. THE SYSTEM MUST BE OPERATING WITH RELEASE 16 OR LATER INSTALLED.
(TIL CD 1083 OR LATER).

This repair involves selectively erasing and reprogramming the Powertrain
Control Module with new software (calibration change).

Connect the MDS (Mopar Diagnostic System) and DRBIII (Scan Tool) to the
vehicle and power them up.
Use the arrow keys and select #2 MDS DIAGNOSTICS on the DRBIII MAIN MENU
Screen.
Use the arrow keys and select DIAGNOSTIC MENU on the MDS, then press NEXT
MENU.
Use the arrow keys and select CONTROLLER PROGRAMMING on the MDS, then press
NEXT MENU.
Use the arrow keys and select PROGRAM CONTROLLER PART on the MDS, then press
NEXT MENU.
Follow the steps presented on the MDS and DRBIII which will allow the DRBIII
to obtain the current part number of the controller.
The MDS will display the part number of the controller on the vehicle and
the appropriate replacement part number, then press NEXT MENU to begin
programming.
If the controller on the vehicle has already been updated or programmed, a
NO UPDATES AVAILABLE message will be displayed. Check the part number of the
controller on the vehicle and compare it to the part number displayed. If
the part numbers match and the controller update has been verified, proceed
to Step 9.

The MDS and DRBIII will prompt for any operator action needed during the
remainder of the programming process.
NOTE: THE FOLLOWING STEPS ARE REQUIRED BY LAW.

Type the necessary information on the "Authorized Software Update Label" and
attach it to the PCM and cover the label with a clear plastic sticker.(See
Illustration)
Type the necessary information on the Authorized Modification label and
attach the label near the VECI Label.(See Illustration)
POLICY:
Reimbursable within the provisions of the warranty.

TIME ALLOWANCE:
Labor Operation No.
Description
Time

08-19-42-97
Module, Powertrain Control Reprogram (1995 BR)
0.5 Hrs.

08-19-42-98
Replace Module, Powertrain Control and Reprogram (1994 BR)
0.7 Hrs.

FAILURE CODE:
Code
Description

FM

Flash Module

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1994 Dodge Dakota Sport(1 of 2,986)
1995 Dodge Dakota Sport(RIP)
2001 Chrysler Sebring LX Sedan(1 of 46)
1989 Dodge Daytona (1 of 1,196)
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North East,Maryland USA
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