SW1 L4-1.9L SOHC VIN 8 (1996)
Malfunction Indicator Lamp: All Technical Service Bulletins
MIL ON - DTC P0141, Rear Heated O2 Sensor & PROM
BULLETIN NO.: 96-T-21A
ISSUED DATE: August, 1996
GROUP/SEQ. NO.: Engine-05
CORPORATION NO.: 686505R
SUBJECT:
MIL On and/or DTC P0141 Stored in PCM Memory (Install New Rear heated Oxygen Sensor and PCM Calibration)
Due to revisions to the VIN breakpoints and Step 1b, this bulletin supercedes bulletin 96-T-21, which should be discarded. Revisions are shown by
double (**) asterisks.
MODELS AFFECTED:
1996 Saturns
CONDITION:
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.
CAUSE:
The rear heated oxygen sensor internal element may be fractured or shorted, causing an inoperative heater friction.
CORRECTION:
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 fails
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.
PROCEDURES
1.
Connect Scan tool to DLC and access diagnostic trouble codes (DTCs).
a.
If DTC P0141 is only DTC present, proceed to step 2 and replace rear heated oxygen sensor.
**
b.
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.**
c.
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 SUPPORTED 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.
