[Gmecm] eeprom programmers HELP

[Jay Vessels]

Hi there!

> i am maybe a confusing guy
> I have the ORIG BCM and ECM yet in the car
> acquired a BRAND NEW ECM for $20 but it came w/o the EEPROM
> My vehicle, as it is, reads ERROR instead of a mileage
> NO ONE has told me definitely (well no 2 people) what needs to be 
> replaced to fix the problem
> EVERYTHING  ELSE works fine

Scott and I have both told you that the BCM, IPC, or one of its 
components (i.e. the EEPROM or the wiring harness) are at fault, so for 
some reason you insisted on buying an ECM, and then wonder why it didn't 
fix it.

If you do not have the Helm manual and are not willing to buy one, or 
you do have it but for some reason cannot follow its diagnostic trees, 
take your car to your local GM dealer.  They can fix it.

There are a variety of computers in your Riv.  The ECM runs the engine, 
the BCM runs just about everything in the rest of the car, and the 
instrument panel cluster (IPC, or gauge cluster) in that car is actually 
another computer.  Not too many GM cars had computerized gauges, but the 
Riviera is one of them, along with the Toronado, Eldorado, and Seville.

The Helm manual for my '89 Eldorado has the following instructions on 
diagnosing "Error" in the odometer:

Key on, enter diagnostics if possible, check for BCM codes B336 or B556, 
and repair if present.

Turn off the headlamp switch and twilight sentinel, and note the 
odometer display.  If it reads "Error":

1)  Remove ALDL cover and jumper pins A&M.
2)  Crank engine for 1 second
3)  Note odometer display:
If all zeros, replace BCM EEPROM.  If "Error", replace instrument panel 
cluster.

Notice that nowhere in there does GM mention the ECM because it is not 
involved in the odometer display.

Jay Vessels
1982 Chevrolet S-10 Sport, 2.8V6 TBI
1984 Chevrolet S-10 Blazer Sport, 2.8V6 (TBI pending)