PCM - DTC P0120 TP/Engine Surge/Sag
NO: TSB-99-13-007DATE: October, 1999
MODEL: 1998-99 Mirage
SUBJECT:
PCM REPROGRAMMING FOR ENGINE SURGE/COLD START/DTC P0120
PURPOSE
Some affected vehicles may experience engine surge at 45-50 mph and/or engine sag during cold start. This may be caused by incorrect powertrain control module (PCM) software parameters resulting in incorrect EGR and air/fuel ratio (but does not affect emission levels). The PCM may also cause the "SERVICE ENGINE SOON" light to come and set Diagnostic Trouble Code P0120. Reprogramming the PCM as described in this bulletin will eliminate these conditions.
However, it is very important to check other vehicle conditions that may affect engine performance before reprogramming the PCM.
AFFECTED VEHICLES
1998-99 Mirage models
PROCEDURE
1. Verify that the base idle speed is within the standard value. Deposits in the throttle valve may affect engine performance. Refer to "Basic Idle Speed Adjustment" in Group 13 of the appropriate Mirage service manual.
2. Perform the appropriate inspection procedures as needed:
^ For hesitation, sag or stumble, refer to Inspection Procedure 15 in Group 13 of the appropriate Mirage service manual.
^ For engine surge, refer to Inspection Procedure 19 in Group 13 of the appropriate Mirage service manual.
! CAUTION
BATTERY VOLTAGE (AS MEASURED AT THE BATTERY POSTS WITHOUT ELECTRICAL LOAD) MUST BE 12.4V OR HIGHER IN ORDER TO REPROGRAM THE PCM.
3. Using the MUT-II scan tool, record any DTCs set in the PCM. If any DTC except DTC P0120 is set, follow the appropriate DTC troubleshooting and repair instructions in the service manual. Then go to Step 4.
4. Use the MUT-II to erase all DTCs set in the PCM.
5. Gather the following reprogramming equipment:
6. Turn the ignition key to OFF and disconnect the MUT-II.
7. Install the red label interface cartridge to the MUT-II. Then install the red memory card and the red label ROM pack. Be sure to use the Mirage ROM pack (Database No. RN99081).
8. Connect the MUT-II to the vehicle. Connect BOTH the 16-pin and the 12-pin data link connectors. (Some 1999 models may have the 16-pin connector taped up to the harness.)
9. Turn the ignition key to ON.
! CAUTION
DO NOT DISTURB THE HARNESS CABLES OR CONNECTIONS. INTERRUPTION DURING THE PROGRAMMING PROCESS COULD CAUSE THE PCM TO LOSE DATA OR PREVENT FUTURE PCM REPROGRAMMING.
10. Select MFI, and press "YES".
11. If the PCM has already been reprogrammed, the MUT-II will display this screen.
NOTE:
The MUT-II will first display a "SUM CHECKING" message for a few seconds, indicating that the scan tool is verifying the ROM-ID.
It this screen is displayed. STOP! Do not continue with this procedure.
12. If the PCM is unable to be reprogrammed, the MUT-II will display this screen.
NOTE:
The MUT-II will first display a "SUM CHECKING" message for a few seconds, indicating that the scan tool is verifying the ROM-ID.
Verify that the correct ROM pack is installed. If the correct ROM pack is installed. and this screen is displayed. replace the PCM. Record this MUT-II screen information and the ROM pack database number on the repair order.
13. If the PCM can be reprogrammed, this screen will display. Press "YES".
14. The MUT-II will display this screen as it reprograms the PCM. It will take a few minutes to complete.
! CAUTION
DO NOT DISTURB THE HARNESS CABLES OR CONNECTIONS. INTERRUPTION DURING THE PROGRAMMING PROCESS COULD CAUSE THE PCM TO LOSE DATA OR PREVENT FUTURE PCM REPROGRAMMING.
15. Press "C".
16. Turn the ignition key to OFF. Reprogramming is complete.
To verify that the correct reprogramming has been made, the ROM ID number will display on the MUT-II screen. The table below shows the vehicle models and their appropriate PCM part numbers ROM ID numbers that display after reprogramming. Also enter the appropriate vendor number listed below.
17. Using a ball-point pen, enter the appropriate PCM part number, vendor number, ROM ID #, this TSB number (TSB-99-13-007), your dealer code, and the current date on the Engine Compartment Label.
NOTE:
If the Engine Compartment Label does not provide a space for the vendor number and ROM ID #, write this information in as shown:
18. Carefully remove all dirt and oil from the vacant area shown on the underside of the hood. Affix the Engine Compartment label in the area shown.
19. Using a ball-point pen, enter the new PCM part number, vendor code, this TSB number (TSB-99-13-007), your dealer code, and the current date on the Control Module Label.
20. Affix the Control Module Label to the PCM, located behind the front passenger side kick panel.
WARRANTY INFORMATION
Use normal warranty procedures for idle adjustment.
PCM Reprogramming
Nature Code: 99D Cause Code: 990
Labor Operation No. 13850A11 Time Allowance: 0.3 hr.
Warranty Coverage: 36 months/36,000 miles.
Special Warranty Information: Normal warranty procedures apply.