PCM - Harsh Initial A/C Engagement
NUMBER: 18-20-99GROUP: Vehicle Performance
DATE: Aug. 20, 1999
SUBJECT:
Harsh A/C Initial Engagement - Clunk Noise
OVERVIEW:
This bulletin involves defining initial harsh A/C engagement and selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software.
MODELS:
2000 (PL) Neon
SYMPTOM/CONDITION:
Some vehicles may intermittently exhibit harsh initial A/C engagement due to liquid refrigerant collecting in the A/C compressor. On initial A/C engagement, after a soak of several hours (or longer), the A/C compressor may make a clunk sound or noise, and the engine may feel rough for a few seconds. If the vehicle is in motion, it may hesitate or stumble.
DIAGNOSIS:
The symptoms and or conditions are difficult to duplicate. If the customer describes any of the above symptoms or conditions, perform the Repair Procedure.
NOTE:
WHENEVER A POWERTRAIN CONTROL MODULE (PCM) IS REPLACED DUE TO FAILURE, THE SOFTWARE OF THE REPLACEMENT CONTROLLER MUST BE VERIFIED FOR THE LATEST REVISION LEVEL. USE THE FLASH PROCEDURE TO UPDATE REPLACED CONTROLLERS AS NECESSARY.
PARTS REQUIRED:
1 04669020 Label, Authorized Software Update
1 04275086 Label, Authorized Modification
EQUIPMENT REQUIRED:
1 CH6OOO Scan Tool (DRB III(R))
1 CH7035 General Purpose Interface Bus Cable (GPIB)
1 CH7OOO/7001 J1962 Cable
1 MDS2
NOTE:
THE MDS2 AND DRB III(R) ARE REQUIRED TO PERFORM PART OF THIS REPAIR. THE MDS2 SYSTEM MUST BE OPERATING AT CIS CD2040 OR HIGHER.
REPAIR PROCEDURE:
1. Log onto the MDS2 system.
2. Connect the MDS2 (Mopar Diagnostic System) and DRB III(R) (Scan Tool) to the vehicle and switch the ignition key to "ON".
3. Use the arrow keys and select # 2 CONNECT TO MDS1 OR MDS2 on the DRB III(R) MAIN MENU SCREEN.
4. Use the arrow keys and select # 2 RUN MDS2 APPLICATION on the DRB III(R) MAIN MENU SCREEN.
NOTE:
ONCE MDS2, DRB III(R) AND VEHICLE COMMUNICATION HAS BEEN ESTABLISHED, THE CANNOT READ VIN FROM DRB III(R) MESSAGE (ON THE MDS2) WILL BE REPLACED BY THE VEHICLE VIN. PRESS THE "OK" BUTTON ON THE MDS2 TO REQUEST A MDS2 SESSION FOR THE VEHICLE VIN INDICATED. PRESS THE "OK" BUTTON WHEN ASKED TO BEGIN SESSION.
5. Push the FLASH tab on the MDS2.
NOTE:
A MESSAGE MAY APPEAR THAT INDICATES NO UPDATES ARE AVAILABLE. IF THIS OCCURS, MAKE SURE YOUR DIAGNOSTIC EQUIPMENT IS OPERATING AT THE LATEST SOFTWARE LEVEL AS LISTED EARLIER IN THIS BULLETIN. IF THE LATEST SOFTWARE IS INSTALLED, AND NO UPDATES ARE AVAILABLE, ANOTHER VEHICLE CONDITION EXISTS THAT WILL REQUIRE FURTHER INVESTIGATION.
6. Select READ PART NUMBERS FROM VEHICLE and click SHOW UPDATES on the MDS2.
NOTE:
A MESSAGE MAY APPEAR THAT INDICATES NO UPDATES ARE AVAILABLE. IF THIS OCCURS, MAKE SURE YOUR DIAGNOSTIC EQUIPMENT IS OPERATING AT THE LATEST SOFTWARE LEVEL AS LISTED EARLIER IN THIS BULLETIN. IF THE LATEST SOFTWARE IS INSTALLED, AND NO UPDATES ARE AVAILABLE, ANOTHER VEHICLE CONDITION EXISTS THAT WILL REQUIRE FURTHER INVESTIGATION.
7. Select the new software part number with the light pen and click UPDATE CONTROLLER SOFTWARE.
8. The MDS2 and DRB III(R) will prompt for any operator action needed during the remainder of the reprogramming process.
NOTE:
THE FOLLOWING STEPS ARE REQUIRED BY LAW.
9. Type the necessary information on the "Authorized Software Update Label" p/n 04669020 (Figure 1). Attach the label to the PCM and cover the label with the clear plastic overlay.
10. Type the necessary information on the "Authorized Modification Label" p/n 04275086 and attach the label near the VECI label (Figure 2).
POLICY: Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No: 08-19-40-91 0.5 Hrs.
FAILURE CODE: FM - Flash Module