ECM Fault code 51 on 1982 - best fix?
Thread Starter
Intermediate
Joined: May 2012
Posts: 46
Likes: 1
From: Orlando, FL
ECM Fault code 51 on 1982 - best fix?
I have a Check Engine fault code 51 which, according to the code reader manual as an ECM problem on my '82. The car does start and run, although it does have a slight miss when cold. Drivability improves as it warms up.
Do I need to replace the ECM ? I noticed that Eckler's sells a rebuilt ECM but they instruct to reuse the PROM from the original ECM. Does anyone have any experience with this particular fault code and what remedy do you recommend? Thanks
Chuck
Do I need to replace the ECM ? I noticed that Eckler's sells a rebuilt ECM but they instruct to reuse the PROM from the original ECM. Does anyone have any experience with this particular fault code and what remedy do you recommend? Thanks
Chuck
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
I have a Check Engine fault code 51 which, according to the code reader manual as an ECM problem on my '82. The car does start and run, although it does have a slight miss when cold. Drivability improves as it warms up.
Do I need to replace the ECM ? I noticed that Eckler's sells a rebuilt ECM but they instruct to reuse the PROM from the original ECM. Does anyone have any experience with this particular fault code and what remedy do you recommend? Thanks
Chuck
Do I need to replace the ECM ? I noticed that Eckler's sells a rebuilt ECM but they instruct to reuse the PROM from the original ECM. Does anyone have any experience with this particular fault code and what remedy do you recommend? Thanks
Chuck
Make sure the plugs at the ECM are in secure. Clear the code and see if it comes back.
You may have some corrosion inside the ECM in the area of the prom. If its not seated right or one of the pins is bent you will get that code. Look for evidence of corrosion.
New ECM's don't come with the prom. You need to swap out yours.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Also make sure any grounding wires/connections are clean and solid. If the Check Engine Light (CEL) is lit when the key is turned to ON position, and it goes out after the engine is started, then the ECM is "working". But, bad electrical/ground connections can cause errors in its data, which could be the reason for the Code 51.
Removing cables, cleaning contacts, and reinstalling with dielectric grease on those connections is the first step in analyzing your problem, since the trouble codes pointed to the ECM. There is no clear indicator of an ECM problem, as a defective ECM would not be reliable/accurate enough to diagnose itself as a problem. An exchange of the ECM is the last item on the list when everything else has been ruled out. Start with clean connections.
Removing cables, cleaning contacts, and reinstalling with dielectric grease on those connections is the first step in analyzing your problem, since the trouble codes pointed to the ECM. There is no clear indicator of an ECM problem, as a defective ECM would not be reliable/accurate enough to diagnose itself as a problem. An exchange of the ECM is the last item on the list when everything else has been ruled out. Start with clean connections.
