ECM trouble dtc 51 PROM error

[TheKOOK]

I recently purchased a 1988 Cheyenne K2500 4X4 and a couple of days ago the truck stalled while idling at a red light and the power seems low when accelerating. I got home and noticed the SES light came on so I checked for any codes and I got code 51 which says there an error with PROM. I removed the ECM and PROM to check for anything unusual but everything appears normal. If I were to replace the PROM which one would be the right one for my truck?

 

[Scooterwrench]

Manual or automatic?
The ECM is more than likely the 1227747 and was used from '87-'91. It could be that somone just grabbed a ECM out of the junkyard and popped it in there and it's not the right prom for your truck.
Here's a list of .bins with the broadcast codes for the 7747 ECM,

1227747 ECM Information $42

1227747 ECM Information $42 This ECM was used in 1987 to 1991 C/K Truck, Van, 4.3L, 5.7L, 5.0L & 7.4L engines. $42 Mask Click here for details on how to read error codes known as Check Engine Light (CEL) or Service Engine Soon (SES) can be found in this thread. *Work in progress*

www.gearhead-efi.com

If your truck has the correct ECM then you may be able to get the right prom for it. The ECM is behind the glovebox in the extreme right corner of the cab. You will have to pull the glovebox liner to access it.

 

[Schurkey]

MAYBE merely disconnecting the battery, removing the PROM, (using standard anti-static protocol) re-seating it, and reconnecting the battery will fix the problem.

 

[TheKOOK]

Manual or automatic?
The ECM is more than likely the 1227747 and was used from '87-'91. It could be that somone just grabbed a ECM out of the junkyard and popped it in there and it's not the right prom for your truck.
Here's a list of .bins with the broadcast codes for the 7747 ECM,

1227747 ECM Information $42

1227747 ECM Information $42 This ECM was used in 1987 to 1991 C/K Truck, Van, 4.3L, 5.7L, 5.0L & 7.4L engines. $42 Mask Click here for details on how to read error codes known as Check Engine Light (CEL) or Service Engine Soon (SES) can be found in this thread. *Work in progress*

www.gearhead-efi.com

If your truck has the correct ECM then you may be able to get the right prom for it. The ECM is behind the glovebox in the extreme right corner of the cab. You will have to pull the glovebox liner to access it.

its an automatic 5.7L

 

[TheKOOK]

MAYBE merely disconnecting the battery, removing the PROM, (using standard anti-static protocol) re-seating it, and reconnecting the battery will fix the problem.

Ill give this a shot.

 

[94GMCK1500]

I have a 94 GMC Sierra K1500 with 5.7... Today the check engine light came on, OBD 1 System and the code was 51... It runs like crap with nothing when accelerator is pushed to the floor... It does move... Had one person said it's the TPS... I replaced the ECM 15 Months back and it only has a 12 month warranty...Few days ago I filled it up and set the trip mileage... I used little over half tank and put less then 200 miles on it... So looking for an idea which route to take... I did read somewhere that for GM, that code also states something about AC switch and abs pump along with mention of TPS....Thanks in advance...

 

[Schurkey]

Download the service manual set for your vehicle from the links in the Sticky thread section of the Engine forum.

Follow the Code 51 diagnostic procedure listed in the manual.

 

[94GMCK1500]

Download the service manual set for your vehicle from the links in the Sticky thread section of the Engine forum.

Follow the Code 51 diagnostic procedure listed in the manual.

I'm sorry, I'm not seeing anything like a sticky thread.

 

[Schurkey]

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[94GMCK1500]

I did find the sticky and downloaded... I did the testing for PCM/ECM and it passed... I tested the TPS, the numbers moved but occasionally seems like its erratic but nothing too serious...When I tested the PCM/ECM, I did hard reset with battery completely disconnected for at least 30 to 40 minutes... Started it up after checking the PROMS for dirt or bent pins... Looked good, so after it was all hooked up, the truck started and ran just fine but still had the previous miss it feels like... So according to what I've read and done, I'll be replacing the plugs and the TPS... Not sure what else could be...