Operation CHARM: Car repair manuals for everyone.
Home >> Honda >> 1997 >> Prelude L4-2156cc 2.2L DOHC (VTEC) MFI >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Technical Service Bulletins >> Engine - Control Module Programming

Engine - Control Module Programming

Bulletin No.
96-054

Issue Date
NOV 4, 1996

Model
1997
PRELUDE

Applicable To
ALL

File Under
ELECTRICAL

Engine Control Module Replacement and Substitution

This service bulletin describes how to program a new engine control module (ECM) for the immobilizer system and explains how to temporarily substitute a known-good ECM for testing purposes. (Information on ECM troubleshooting is in section 11 of the 1997 Prelude Service Manual.)

During engine starting, the ECM receives a coded signal from the immobilizer control unit. This signal must match the code stored in the ECM's memory. If the signal matches, the ECM functions normally. If the signal does not match, the ECM disables the fuel system (fuel pump and injectors).

WARRANTY CLAIM INFORMATION

None. This Service Bulletin is for information only.

ECM REPLACEMENT

If you replace an ECM or if you make new keys, the ECM must be programmed to accept the immobilizer control unit's coded signal.

To program the ECM, you need the PGM Tester with SN 701 or later software on a 4MB program card. You also need the password code for the program card. (If you do not know the password code, ask your Service Manager for it, or find it on the HONDANET 2000 VIN Status Inquiry display.)





1. Connect the PGM Tester, and turn the ignition switch ON (II).

2. Select IMMOBI from the MAIN menu.

3. Select REWRITE from the IMMOBI menu.

4. Select ECM from the REWRITE menu. Continue to follow the screen prompts until ECM programming is completed.

ECM SUBSTITUTION

(For Testing Purposes Only)

If you take a known-good ECM out of a "donor car" to use for testing purposes, you have to disable the known-good ECM's immobilizer function. With this function disabled, the ECM does not need a coded signal from the immobilizer control unit to operate the fuel system.

To disable the ECM's immobilizer function, you need the PGM Tester with SN 701 or later software on a 4 MB program card. You also need the donor car's VIN and the donor car's four-digit immobilizer disable code. (Find this code using the HONDANET 2000 system.)

1. Remove the ECM from the donor car, and install it in the car you are testing.

2. Connect the PGM Tester to the car you are testing, and turn the ignition switch ON (II).

3. Follow the prompts on the PGM Tester screen.

4. When the PGM Tester asks for the VIN, enter the donor car's VIN.

5. When the PGM Tester asks for the odometer reading, push the ENTER button. (The odometer reading is not needed.)

6. Select IMMOBI from the MAIN menu.

7. Select CANCELLATION from the IMMOBI menu.

8. Select CANCELLATION from the CANCELLATION menu.

9. Follow the screen prompts on the PGM Tester. When requested, enter the donor car's four-digit immobilizer disable code.

10. When you complete the procedure, the last screen on the PGM Tester indicates "Immobilizer has been cancelled."

11. Perform the needed tests on the car you are working on.

NOTE:
The ECM functions in the disable mode for 50 starts. After you start the engine 50 times, the ECM cancels the disable mode and returns to normal operation. Loss of battery voltage (disconnecting the ECM) does not cancel the disable mode.

12. Reinstall the known-good ECM into the donor car after you perform the needed tests.

NOTE:
When you reinstall the ECM in the donor car, it will recognize the coded signal from the immobilizer control unit, cancel the disable function, and return to normal operation. The immobilizer system in the donor car will then be fully functional.
pro multis · About Operation CHARM