Service Procedure

The following service procedure is to be performed on certain 1991-1995 model Cadillac vehicles equipped with the 4.9 liter engine (RPO L26), which can be easily identified by the character "B" in the 8th position of the Vehicle Identification Number.

It is important to note that some 1991 and 1992 model vehicles built before October 24, 1991 may have experienced warranty repairs with a labor operation code of T6527 or J6364 and received the prom being recalled as a service part. VIN breakpoints for 1992 model vehicles are:

247930 for DeVille 604013 Eldorado 806499 for Seville

Affected 1991 model vehicles and 1992 model vehicle built before these breakpoints should be inspected and repaired if necessary. Dealers must confirm vehicle eligibility through the Vehicle Information Service System (VISS) and/or their "involved vehicle listing" prior to performing this inspection. All 1992 model vehicle built after the breakpoints require Mem-Cal replacement using the following procedure.

1. Determine the PROM ID number by using the appropriate procedure which follows. Note that the use of a Tech 1 diagnostic tool for this purpose is specifically NOT recommended.

^ Turn ignition key to the "RUN" position.

^ Simultaneously press and hold the "OFF" and "WARMER" buttons on the Electronic Climate Control (ECC) panel until all segments on the ECC and Fuel Data Center (FDC) panel are illuminated. Then release the buttons.

A. All 1991-1993 model C

^ Observe the FDC panel. Any Powertrain Control Module (PCM) or Body Control Module (BCM) Diagnostic Trouble Codes which may be present will be displayed on the FDC panel. Codes will be stored in memory as either history or current codes. Any PCM history codes will appear first preceded by ..E. Any PCM current codes will then be displayed preceded by E.E. The same sequence will follow for any BCM codes. BCM codes will follow ..F and F.F readouts for history and current codes respectively. Record all codes on the repair order for use in diagnosing other possible customer service needs.

^ After all Trouble Codes have been displayed .7.0 will display.

^ When .7.0 appears on the FDC, press the "LO" button on the ECC panel to access PCM data. E.9.0 will display. Press the "LO" button again and P.2.5 will display. The PROM ID number will be displayed as a three digit code following P.2.5. Record PROM ID number on the repair order.

B. All 1991-1993 model E/K (Except 1993 model ETC, STS, Eldorado Sport Coupe) and 1994-1995 model Ksp except those registered in the State of California. Note that DeVille Concours is not included.

^ Observe the Driver Information Center (DIC). All history or current Powertrain Control Module (PCM) Instrument Panel Cluster (IPC) Air conditioning programmer (ACP), Supplemental Inflatable Restraint (SIR) and Traction Control System (TCS) codes which are present will be displayed in that order followed by PCM?. Record all codes on the repair order for use in diagnosing other possible customer service needs. After PCM? is displayed, press "HI" to access PCM DATA?. Press "HI" again to enter PCM parameters and PDO1 will display. Press "LO" and PD99 will display preceded by the 3 or 4 digit PROM ID number. Record PROM ID number on the repair order.





Notice:
On 1991 and 1992 model vehicle only, if the PROM ID is the number, listed in Table 1 of this bulletin, or a lower number, the Mem-Cal should NOT be replaced. Proceed to Step 19.














2. After determining the PROM ID number of the Mem-Cal which is currently installed in the vehicle, refer to Table 2 of this bulletin. Find the model year, carline and emission system of the vehicle being serviced. Identify the old Prom ID number as recorded on the repair order. Determine the new Prom ID number and Mem-Cal part number to be installed in the PCM as indicated on the right side of the table.

Caution:
To prevent internal PCM damage, the ignition must be "off" when disconnecting or reconnecting power to the PCM.

The Mem-Cal and PCM are sensitive to electrostatic discharge. Follow these procedures before handling these components to reduce any possible electrostatic charge build up on the technician's body and inadvertent discharge to the electronic part:

a. Always touch a known good ground before handling these components. This should be repeated while handling the part and more frequently after sliding across a seat, sifting down from a standing position or walking a distance.

b. Avoid touching the electrical terminals of the part unless instructed to do so by a written diagnostic procedure.

c. Do not remove a part from its protective package until it is time to install it.

d. Before removing the part from its package, ground the package to a known good ground on the vehicle.

Mem-Cal/Prom Removal

Before proceeding to step 3, determine the AM and FM radio station which have been per-set by the customer. Write them on the repair order. The battery electrical disconnect will result in loss of both clock time and all pre-set radio stations. Resetting the clock to the correct time and the radio to the customer's preferred stations before returning the vehicle is a courtesy which will be sincerely appreciated.

3. Turn ignition key to "OFF" position and disconnect the negative battery cable.

4. Remove right hush panel.

5. Remove the three (3) electrical connectors to PCM.

6. Remove PCM retaining nut.

7. Pull PCM rearward to disengage the top mounting pins and remove the PCM from the passenger compartment.

8. Remove Mem-Cal access cover from the PCM and remove Mem-Cal. When removing the Mem-Cal use two fingers and push both retaining clips from the Mem-Cal at the same time. Grasp the Mem-Cal at both ends and lift from the Mem-Cal socket.

Mem-Cal Installation

9. Align the notches on the Mem-Cal with the notches in the Mem-Cal socket. Gently press on the ends of the Mem-Cal until it is seated in the socket. Do not press on the middle of the Mem-Cal. Push the clips onto the sides of the Mem-Cal until they snap into place. Listen for the click from each end.

10. Install the Mem-Cal access cover onto the PCM.

11. Place the PCM onto the mounting bracket, slide the PCM forward to engage the top mounting pins and install the PCM retaining nut.

12. Install the three (3) electrical connectors to the PCM.

13. Reconnect negative battery cable.

14. Start the engine. Engine should start and run. Turn engine off.

^ Functionally check the PCM/Mem-Cal by turning the ignition to "RUN" and enter diagnostics as described in Step 1. Code E52 and B552 (1991 model E/K and 1991-1993 model C only ) or Codes P052 HISTORY and 1052 HISTORY (1992-1993 model E/K and 1994-1995 model Ksp only) will appear and must be cleared.

^ Clear code E52 by pressing "OFF" and "HI" simultaneously. Press any ECC panel button to exit diagnostics. If diagnostic Code F32 or B334 or 1034 appears on the display, the Mem-Cal is not fully seated or is malfunctioning. If it is necessary to remove and reinstall the Mem-Cal, follow the procedures listed in Steps 3 through 14.

^ To clear codes P052 HISTORY and 1052 HISTORY wait until PCM? displays. After PCM? is displayed press "HI". PCM DATA? should display. If PCM DATA? is not accessible or a NO PCM DATA message is displayed, verify that the PCM contains the correct PROM, that the PCM connectors are correctly installed, and the PCM fuses in the engine compartment fuse block are present and not blown (see page 8A-20-0 in the appropriate Service Information Manual). Press "LO" four times until PCM CLEAR CODES displays. Press "HI" to clear all PCM codes. Press "LO" twice to display IPC?. Press "HI" to display IPC DATA? followed by "LO" three times to display IPC CLEAR CODES?. Press "HI" to clear all IPC codes. Press "DEFOG" to exit diagnostics.

15. Once engine operation is verified, perform the following TPS/Idle Learn Procedure. Note that in order to perform this procedure the outside temperature must be above 10 degrees Celsius (50 degrees Fahrenheit) to enable A/C compressor operation and the engine coolant temperature must be above 80 degrees Celsius (176 degrees Fahrenheit) to insure PCM closed loop operation. Check engine coolant temperature as follows:

A. All 1991-1993 model C

^ Enter diagnostics by simultaneously pressing the "OFF" and "WARMER" buttons on the ECC panel. After .7.0 displays on the FDC panel press the "LO" button to display E.9.0. Press "HI" four times to display P.0.4 which will be followed by the coolant temperature displayed in degrees Celsius.

B. All 1994-1995 model Ksp

^ Enter diagnostics by simultaneously pressing the "OFF" and "WARMER" buttons on the ECC panel. When PCM? displays on the DIC panel, press "HI" to display PCM DATA?. Press "HI" four more times to display P.0.4 which will be followed by the coolant temperature displayed in degrees Celsius.

C. All 1991-1993 model E/K

^ Coolant temperature, in degrees Fahrenheit, may be displayed on the DIC by pressing and releasing the "ENG DATA" (1991 model E/K) or "INFORMATION" (1992-1993 model E/K) button until it appears.

TPS/Idle Learn Procedure

a. Starting from the ignition "OFF" position, wait a minimum of 20 seconds then turn the ignition to the "RUN" position (engine not running).

b. Enter diagnostics by simultaneously pressing the "OFF" and "WARMER" buttons on the Electronic climate Control (ECC) panel.

c. Turn the ignition to the "OFF" position.

d. Wait a minimum of 20 seconds then turn the ignition to the "RUN" position (engine not running).

e. Enter diagnostics by simultaneously pressing the "OFF" and "WARMER" buttons on the ECC panel.

f. Turn the ignition to the "OFF" position.

g. Wait a minimum of 20 seconds then start engine.

h. With the engine running, apply brakes and place transaxle in "DRIVE" range.

i. Turn the ECC to "OFF" and allow the engine to idle for at least one minute (foot off the accelerator).

j. Turn the ECC to "AUTO" and verify that A/C compressor engagement occurs. Allow engine to idle for at least one minute (foot off the accelerator).

k. Place transaxle in "PARK" range and turn engine off.

16. Install hush panel.

17. Destroy the Mem-Cal removed from the vehicle by crushing it in a vise or press. Wear safety goggles or other protective eyewear when performing this procedure.

18. Reset the clock to the correct time and the AM and FM radio stations to those which were previously set by the customer.

19. Install Campaign Identification Label.

20. California Dealers Only: Provide the customer with a "Vehicle Emission Recall Proof of Correction" certificate.