MIL ON - DTC P0300 ECM Software
05.1-08DATE:
11/95
Sedan Range
MODEL:
1996 MY
Sedan 4.0 NA
VIN
754304-764078
MIL Illumination - DTC P0300 - Service Action S659
ISSUE:
Some 1996 MY vehicles within the above VIN range may experience illumination of the Malfunction Indicator Lamp (MIL) caused by DTC P0300 being set. The DTC is set due to close software tolerances in the ECM rather than a mechanical problem with the engine.
This condition can be rectified by replacing one or both of the Programmable Read Only Memories (PROMs), depending on the VIN, with new PROM(s) from the appropriate modification kit.
ACTION:
NOTE:
Inspect all vehicles within the above VIN ranges for a square yellow ECM rework identification label. This label is located in the tool box area, Illustration 7. Also check for the PECUS label on the ECM, Illustration 6.
If no rework labels are present, replace the PROM(s). If possible, this action should performed during PDI prior to the sale of the vehicle. For vehicles already in service, the modification should be done at the first service opportunity, or in case of a customer complaint.
PREPARATION
1. Connect the PDU to the vehicle and check for any DTCs stored in the ECM.
2. Record any DTCs found on a form S-93, then clear them from the system.
3. Turn the ignition OFF Wait 20 seconds, then disconnect the vehicle battery.
REMOVING ECM
1. Remove the right side A-pillar trim.
2. Remove the trim panel mounting bracket.
3. Remove the ECM retaining bolt and disengage the upper spade mounting of the ECM from the slot in the A-pillar.
4. Disconnect both harness multi-plug connectors from the ECM and remove the ECM from the vehicle.
REPLACING PROM - ALL MODELS
ECM tools required:
^ One Anti-static pad, Part No. JAG 205/ST010,
^ One PROM removal tool, Part No. JAG A 999/ND
^ One TX 20 Torx Tamper-proof screw bit, JAG T20, and
^ One S659 Training video have been supplied for this Service Action procedure. Review the video for general rework guidelines prior to performing this procedure.
CAUTION!
The following steps should only be carried out while working at an anti-static workstation (Illustration 1) and wearing a grounding wrist strap.
1. Position the ECM on the anti-static workmat so that when facing the multiplugs, the red multi-plug is at the upper right and the black multi-plug to the lower left.
2. Note the position of the top cover with its mounting tab to the ECM housing. Mark both the cover and the casing using a felt tip marker to assist reassembly. Remove the four tamper resistant retaining screws of the top cover (the cover adjacent to the red multi-plug) using a Torx 20 Anti-Tamper screw bit.
3. Obtain a wooden block approximately 6x6x1 inches. Remove the seven retaining screws of the printed circuit board (Illustration 2). Lift the printed circuit board and support it on the wooden block so that no strain is applied to the ribbon connectors. Allow a clearance space so that no damage can occur from contact with the mounting brackets.
4. Base on VIN application, the modification kit contains ONE or TWO PROM microchips. Single-chip kits include one 28-pin chip. Two-chip kits contain a 28-pin chip and a 32-pin chip. Remove the appropriate PROM cover(s) by lightly gripping the PROM cover with a pair of pliers and using a side to side rocking action.
5. Use a suitable chip removal tool to carefully remove one or both PROM chips from the printed circuit board (Illustration 3). The PROM removal tool supplied may differ from that shown in the illustration.
6. Before installing the new microchip(s), identify the semicircular cutouts in both the chip and the socket on the printed circuit board (Illustration 4). The two cutouts must be aligned as the chip is inserted into the socket.
NOTE:
To aid in installing the PROM, an installation tool can be sourced at a local electronics supply store.
Careful manual alignment and installation methods must be used at this point in the procedure.
7. Identify and install the replacement 28-pin chip from the kit into the 28-pin socket and, where applicable, the 32-pin chip into the 32-pin socket.
CAUTION!
The microchip MUST lie parallel to the printed circuit board with all the pins engaged into the socket (condition A, Illustration 5). Permanent damage to the chip is likely in conditions B or C. Malfunctions will occur with partial engagement as in condition D.
8. Install the original cover(s) over the PROM chip(s).
9. Carefully fold the printed circuit board back into its original location on the housing of the ECM. Make sure the multi-plug is correctly aligned with its location in the housing. Install the seven retaining screws. Torque the screws to 20 - 25 lb. in. (2.25 - 2.82 Nm).
10. Install the ECM cover on the housing aligning the marks made during disassembly. Install the four mounting screws. Torque the screws to 20 - 25 lb. in. (2.25 - 2.82 Nm).
11. Apply the PECUS label from the kit to the cover near the existing labels without covering them (Illustration 6).
12. Install the ECM by reversing the removal procedures.
13. Apply the 1 in. square yellow rework identification label from the kit in the engine compartment as follows:
Sedan Range:
On the floor of the tool box on the right side of the engine compartment (Illustration 7).
14. Connect the battery and reset the vehicle clock.
15. Start the vehicle and perform an adequate road test to verify proper engine operation. Use the PDU to check the orientation of the oxygen sensors and perform the engine setup only if a driveablity complaint exists.
PARTS INFORMATION:
DESCRIPTION PART NUMBER QTY
Modification kit for Sedan Range RTH 1000
VIN 754304 - 757829
Modification kit for Sedan Range RTH 1002
VIN 757830 - 764078
PARTS CROSS REFERENCE:
WARRANTY INFORMATION:
Service Action S659
CLAIM SUBMISSION PROCEDURE:
Warranty summary codes have been assigned to this service action in order to simplify claim submission. The dealership will be reimbursed the parts and labor time allowance as indicated.
DCS DEALERS
Submit claims using the appropriate summary code for the vehicle model and work performed. Follow standard campaign submission procedures.
NON-DCS DEALERS
Submit claims on the Recall Campaign Summary form W-25. Enter the appropriate summary code for the vehicle model and work performed in the Repair Code column. Do not use the W-1 warranty claim form.