Oil Pressure Gauge - Inoperative Or Needle Fluctuates

NO: 08-07-96 Rev. A

GROUP: Electrical

DATE: Sept. 27, 1996

SUBJECT:
Oil Pressure Gauge - Inoperative Or Needle Fluctuates

NOTE : THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETINS NUMBERED 08-49-95 DATED 11/10/95 AND 08-07-96 DATED 3/25/96, WHICH SHOULD BE NOTED OR REMOVED FROM YOUR FILES. THIS BULLETIN COMBINES BOTH OF THE PROCEDURES AND ADDS THE REPLACEMENT OF THE OIL PRESSURE SENSOR. THE CHANGES ARE HIGHLIGHTED WITH ASTERISKS.

MODELS:

1996 (ZJ) Grand Cherokee
1996 (ZG) Grand Cherokee (export)

SYMPTOM/CONDITION:

The oil pressure gauge may be inoperative, show erratic readings or excessive needle fluctuations.

DIAGNOSIS:

Using the Mopar Diagnostic System (MDS) or the Scan Tool (DRB III) and appropriate Diagnostic Procedure Manual, verify that all engine systems are functioning correctly. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order for future reference and repair as necessary. If the above condition exist, perform the repair procedure.

EQUIPMENT/PARTS REQUIRED:

1    CH6000         Scan Tool (DRB III)
1    CH7035         General Purpose Interface Bus Cable (GPIB)
1    CH7000         J1962 Cable
1    4669020        Label - Authorized Software Update
1    4275086        Label - Authorized Modification
**1  56031003       Oil Pressure Sensor**

REPAIR PROCEDURE:

This bulletin involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software (calibration change), checking the polarity of the oil pressure sensor harness and replacing the sensor.

NOTE : MDS AND DRB III ARE REQUIRED TO PERFORM THE FOLLOWING REPAIR. MDS MUST BE OPERATING WITH RELEASE 19 OR HIGHER AND TIL 1101 OR HIGHER INSTALLED.

1. Connect the MDS and DRB III to the vehicle and power them up.

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

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

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

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

6. 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.

7. 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 a system problem actually exists and should be corrected.

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

NOTE :YOU MAY BE REQUIRED TO REPROGRAM THE VIN AND ALL OPTIONS INTO THE UPDATED PCM. THIS WOULD BE THE SAME PROCEDURE THAT YOU WOULD USE IF YOU ARE INSTALLING A NEW PCM.

NOTE : THE FOLLOWING STEPS ARE REQUIRED BY LAW.

9. Type the necessary information on the "Authorized Software Update" label, P/N 4669020. Attach the label to the PGM and cover the label with the clear plastic overlay.

10. Type the necessary information on the Authorized Modification Label and attach the label near the VECI Label.

CAUTION : REVERSED POLARITY IN THE OIL SENSOR HARNESS CAN CAUSE DAMAGE TO THE NEW OIL PRESSURE SENSOR. BE SURE TO CHECK AND CORRECT THE HARNESS POLARITY PRIOR TO INSTALLATION OF THE NEW SENSOR.

11. Using a digital volt meter. Check for a 5 volt feed at terminal 2 of the oil sensor connector (see Figure 2). If the 5 volt feed is not present at terminal 2, the polarity of the wires are reversed, disassemble the connector and reverse the wires to assure that terminal two is the feed.

12. Remove the oil pressure sensor and install P/N 56031003, tightening the sensor to 14 Nm (120 in. lbs.)

TIME ALLOWANCE:

Labor Operation No: **08-46-10-90                           0.8 Hrs.**

FAILURE CODE:       P8 - New Part