TSB 18-24-98

Light Spark Knock Timing Retard Feature

Visit Geno's Garage for Truck accessories.

Date: Jul. 31, 1998

Models: 1996 - 1997 (BR) Ram Truck

1996 -1997 (AB) Ram Van
1996 -1997 (AN) Dakota
1996 - 1997 (BR) Ram Truck
1996 - 1997 (XJ) Cherokee
1996 - 1997 (ZJ) Grand Cherokee
1996 - 1997 (ZG) Grand Cherokee (international Markets)

NOTE: THIS INFORMATION APPLIES TO VEHICLES EQUIPPED WITH A 2.6L, 4.OL, 3.9L, 5.2L AND 5.9L LIGHT DUTY GASOLINE ENGINES.

Symptom/Condition:

Some vehicles may exhibit light spark knock with a warm engine under load.

Discussion:

Determine when the customer exhibits this condition and verify it by driving the vehicle in similar conditions. If the vehicle exhibits light spark knock with a warm engine under load perform the flash update procedure. Once the flash procedure is completed, spark advance/retard may be adjusted.

Diagnosis:

Select DRB III stand alone, current model year diagnostics, engine, and miscellaneous. When in miscellaneous, spark advance will be available. Use the arrow keys to retard timing in 2 degree increments to a maximum of -4deg'. When the DRB lll screen reads 0 the vehicle will be set at maximum advance and when at -4 it will be set at maximum retard.

NOTE: THE IGNITION KEY MUST BE CYCLED FOR THE CHANGES TO TAKE EFFECT.

After performing the spark advance/retard feature, drive the vehicle to verify that the light spark knock is gone.

This feature will not compensate for heavy spark knock conditions. If heavy knock is experienced, further diagnosis and testing will be required.

Repair:

This Procedure involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software.

NOTE: The MDS and DRB III are required to perform this repair and the system must be operating with release 21 or higher AND TIL CD RELEASE 1165 or higher must be installed. The DRB III must be operating at release 25.5 or higher.

1 .    Connect the MDS (Mopar Diagnostic System) and DRB III (Scan Tool) to the vehicle and power them up.

2.     there was no 2 in this set of instructions!

3.    Use the arrow keys and select #2 MDS DIAGNOSTICS on the DRB III MAIN MENU Screen.

4.    Use the arrow keys and select DIAGNOSTIC MENU on the MDS, then press NEXT MENU.

5.    Use the arrow keys and select VEHICLE CONTROLLER PROGRAMMING on the MDS, then press NEXT MENU.

6.    Use the arrow keys and select PROGRAMMING OF ALL OTHER CONTROLLERS USING MI)S & DRBIII on the MDS, then press NEXT MENU.

7.    Follow the steps presented on the MDS and DRB III which will allow the DRB III to obtain the current part number of the PCM.

8.    The MDS will display the part number of the PCM on the vehicle and the appropriate replacement part number, then press NEXT MENU to begin programming.

If the PCM on the vehicle has already been updated or programmed, a NO UPDATES AVAILABLE message will be displayed. Check the part number of the PCM on the vehicle and compare it to the part number displayed. If the PCM has already been updated, then another condition exists that will require further diagnosis and repair.

9. The MDS and DRB lllo will prompt for any operator action needed during the remainder of the programming process.

 The following steps are required by law:

 

10.    Type or print necessary info on the "Authorized Software Update" label (Fig 1) and attach it to the ECM. Cover the label with clear tape.

11.    Type or print the following information on the Authorized Modification Label and attach the label near the VECI label (Fig 2).

notes:

Policy: Reimbursable within the provisions of the warranty

Time Allowance:
Labor Operation No:       08-19-41-96 . . . . . . . . .0.5 Hrs.

Failure Code:   FM - Flash Module