MIL On and/or DTC P0141 Stored in PCM Memory

The malfunction indicator lamp (MIL) (SERVICE ENGINE SOON telltale lamp) may be On with diagnostic trouble code (DTC) P0141 stored in powertrain control module (PCM) malfunction history.

The rear heated oxygen sensor internal element may be fractured or shortened, causing an inoperative heater function.

Refer to the following procedures to repair this condition. After condition is repaired, download a new service calibration on vehicles built before and including VIN TZ201459 (automatic transaxle) or VIN TZ201811 (manual transaxle). This new calibration revises parameters that result in false for inactivity of the rear heated oxygen sensor, preventing DTC P0140.

Important: The new service calibration does not have to be installed on vehicles built after the above VIN breakpoints.

1. Connect Scan tool to DLC and access diagnostic trouble codes (DTCs).

1.1.	If DTC P0141 is only DTC present, proceed to step 2 and replace rear heated oxygen sensor.

1.2.

If DTCs P0440, P0443 or P1406 are present along with DTC P0141, check the EGR fuse located in the underhood junction block (UHJB). If the fuse has opened, disconnect the rear heated oxygen sensor and verify that the short is no longer present. If short is no longer present, replace the EGR fuse and proceed to step 2 and replace the rear heated oxygen sensor.

1.3.	If the short remains, refer to the appropriate diagnostics in the "1996 Powertrain Controls Service Manual" to repair the condition. After condition has been repaired, proceed to step 14 of this bulletin, and if applicable, download the new service calibration.

2. Disconnect negative battery cable.

Caution: MAKE SURE VEHICLE IS PROPERLY SUPPOSED AND SQUARELY POSITIONED. TO HELP AVOID PERSONAL INJURY WHEN A VEHICLE IS ON A HOIST, PROVIDE ADDITIONAL SUPPORT FROM THE OPPOSITE END FROM WHICH COMPONENTS ARE BEING REMOVED. MAKE SURE HOIST DOES NOT CONTACT FUEL OR BRAKE LINES.

3. Raise vehicle squarely on a hoist.



4. Remove rear heated oxygen sensor wiring harness from the cradle by pushing up on retaining clip tab.
5. Remove connector position assurance (CPA) device and disconnect rear heated oxygen sensor wiring harness from engine wiring harness.
6. Remove the rear heated oxygen sensor wiring harness from the three - way catalytic converter heat shield trough by gently pushing the wiring harness from its retaining clips.





7. Remove rear heated oxygen sensor using Saturn tool SA9603E. If necessary, use a liquid penetrate before removing rear heated oxygen sensor.

Notice: The rear heated oxygen sensoruses a permanently attached pigtail and connector. This pigtail should not be removed from the oxygen sensor. Damage to, or removal of, the pigtail or connector could affect proper operation of the rear heated oxygen sensor.

Notice: Service replacement oxygen sensors have a sufficient amount of anti--seize compound; therefore, additional anti--seize compound is not recommended.

8. Install rear heated oxygen sensor using Saturn tool SA9603E.

Tighten
Torque 45 N·m (33 lb ft)





Notice: Make sure to center the white marker tape on the rear heated oxygen sensor pigtail with the edge of the trough. The white marker tape must be centered with the edge of the trough to ensure there will be no stress on the sensor connection.

9. Connect rear heated oxygen sensor wiring harness connector into engine wiring harness connector.
10. Install the connector position assurance (CPA) device into electrical connector.
11. Install rear heated oxygen sensor wiring harness retaining clips into cradle.
12. Lower vehicle.
13. Connect negative battery cable.
14. On vehicles built before and including VIN TZ201454 (automatic transaxle) or VIN TZ221884 (manual transaxle) select the following through the Scan tool menus:

14.1.

1996 Vehicle

14.2.

PCM/EC

14.3.

SCANNER

14.4.

VEHICLE ID TABLE

14.5.

Compare END MODEL # to the following "1996 Purge Diagnostic Enhancement Calibrations" chart:

•

If End Model # Displayed on Scan tool is listed in the "PRIOR END MODEL #" column, download a new service calibration using EEPROM programming feature of the service stall system (SSS). (Refer to "PCM Flash Programming" under "General Description" in the "PCM Serial Data" section of the "1996 Revised Powertrain Controls Service Manual," or the "Service Stall Users Guide" for proper programming procedures.)

•	If the End Model # displayed on Scan tool is listed in the "END MODEL #" column, the new service calibration has already been downloaded and there is no need to download a new service calibration.

25167115 - Sensor Asm - Heated Oxygen

To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System for J6380 (replace rear hated oxygen sensor), or if another procedure is performed, refer to the appropriate Electronic Labor Time Guide for the correct Labor Operation Code and Time.