PROM - Revised PCM Calibration Enhancement
File In Section: 6E - Engine Fuel & EmissionBulletin No.: 77-65-07A
Date: September, 1997
INFORMATION
Subject:
PCM Calibration Enhancement
Models:
1997 Cadillac Concours, DeVille, Eldorado, Seville
1997 Oldsmobile Aurora with 4.0L, 4.6L Engines
(VINs C, Y, 9 - RPOs L47, LD8, L37)
This bulletin is revised to include the 1997 model year commercial chassis calibration.
Please discard Corporate Bulletin 77-65-07 (Section 6E - Engine Fuel & Emission).
A PCM calibration enhancement has been released for the 4.0L and 4.6L engines identified above and built before February 1, 1997. This PCM calibration can be used to service 1997 model year 4.0L and 4.6L engines with the following DTCs after following the complete instructions for each DTC code listed below.
DTC DTC Description
P0135, P0141,
P0147, P0155 O2 Heater Code
P0133, P0153 O2 Response Slow Time
P1134, P1154 O2 Ratio of Response Times
P1140 O2 Response Ratio Pre-Converter O2
P0325 Knock Sensor Module Circuit
P0401 EGR System Malfunction
Surge Light-load surge at 30-35 MPH
If any of the DTCs above are present, carefully follow the steps listed below:
Procedure
1. BUILT BEFORE FEBRUARY 1997 If the vehicle was produced prior to February 1, 1997, proceed to step 2 below. If the vehicle was produced after February 1, 1997, consult the diagnostic procedures for the specific DTCs listed in Section 6E of the applicable Service Manual.
2. PREVIOUS UPDATE WITH TECHLINE CD ROM DISC # 11997
If the vehicle was updated with an enhanced calibration from Techline CD ROM Disc # 11997, consult the diagnostic procedures for the specific DTCs listed in Section 6E of the applicable Service Manual. If the vehicle was not updated with an enhanced calibration from Techline CD ROM Disc # 11997, proceed to the specific DTC listed below and follow the instructions for that DTC completely.
Important:
All DTCs, technician observations, and customer comments are to be recorded on the repair order in accordance with article 1 .6.2G of the General Motors Service Policies and Procedures Manual.
^ For O2 Heater DTCs P0135, P0141, PO147, P0155:
Verify O2 heater operation using the Service Manual Section 6E DTC diagnostic chart codes. Follow the DTC diagnostic chart until the heater fault is not present. Update the PCM with applicable calibration; do NOT change the oxygen sensor.
^ For O2 Response and Ratio DTCs P0133, P0153, P1134, P1154:
- Verify O2 heater operation using the Service Manual Section 6E diagnostic chart codes. Follow the DTC diagnostic chart to the point it becomes necessary to replace the oxygen sensor. Update PCM with applicable calibration; do NOT change oxygen sensor.
- Verify the repair using the Tech II device.
^ For O2 Response Ratio Pre-Converter O2 DTC P1140:
- Verify O2 heater operation using the Service Manual Section 6E diagnostic chart codes. Follow the diagnostic chart to the point it becomes necessary to replace the oxygen sensor. Update the PCM with applicable calibration; do NOT change the oxygen sensor.
- Verify the repair using the Tech II device.
^ For Knock Sensor Module Circuit DTC P0325:
Update the PCM with the applicable calibration before using the published Service Manual diagnostic procedure if a low battery voltage condition along with extended crank condition may have been present during the setting of DTC P0325.
^ For EGR System Malfunction DTC P0401:
This DTC is more likely to set by frequent vehicle hot restarts in high ambient temperatures. Verify there are no induction system leaks. If no induction system leaks are found, proceed to the Service Manual DTC diagnostic chart. If, at Step 7 of the DTC diagnostic chart, the answer is "YES," update COM with the applicable calibration.
^ For Surge:
If a vehicle exhibits surge at low speeds of 30 to 35 mph under light load conditions or at the 1-2 shift under minimal throttle, update the PCM with the applicable enhanced calibration.
Parts Information
After following the specific instructions outlined above and/or the necessary procedures in the Service Manual have been performed indicate that a calibration enhancement is required, update the vehicle with the applicable enhanced calibration listed below:
Warranty Information
For 1997 Cadillac Concours, DeVille, Eldorado, Seville, Commercial Chassis, and Oldsmobile Aurora models repaired under warranty, use:
Labor Operation Description Labor Time
J6355 PROM, Reprogramming 0.4 hr
On Car