Replacing ECU/ECM

[95 LeSabre]

How hard is it? Is there a write-up on this some where? Thanks guys!

[bigj-dog]

Don't know for sure about a `95, but I switched one in a `94 last week. Just remove the lower dash panel below the glove box (it actually stretches over to the gas pedal). Slide the computer out of it's white plastic holders and uplug the 3 connectors (red,white,blue). Make sure if you have bought a used computer that you remove the prom from yours and install it in the new one. Take the two screws out of the cover and unplug/replug.

[Smith1000]

In the 97, the computer is under the hood near the left front corner. I think they moved the ECU for the 97 Lesabres. I don't think there is a PROM for the 97, so it has to be programmed. The older ones are easier to deal with. I had an Olds that had the ECU behind the glove box. It took about 30 minutes to replace. Like stated, just had to transfer the PROM to the new ECU and reinstall.

[95 LeSabre]

What is the prom and what does it look like? How do I remove it? Do I remove the silver case?

[HotZ28]

Some 95's have OBD1 and some had OBD11. If the computer is under the hood, it is OB11. If it is under the dash (passenger side) it is OBD1. The OBD1 has a prom chip that has engine operating parameters in burned memory.

If your unit is under the dash, remove it and you will see two screws holding a cover on the box. Remove the cover and look inside and you will see a removable chip. Transfer the chip to the new unit, and you are ready to go.

OBD11 systems are preprogrammed and do not have a chip. It operates similar to software in a computer.

[95 LeSabre]

Do I need to disconnect the battery?

[bigj-dog]

yep