EEC-IV code 511 - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

fox-body · 11-14-2009, 15:30

Hi, I have 93 Thunderbird 3.8 LX. Sporadic the "Check Engine" light comes on and the car lose its power. The EEC-IV gives a code 511, does this mean that the computer is broken or could it be something else?

**Bert** · 11-14-2009, 15:42

That code means: No power to PCM pin 1 or bad PCM (processor)

fox-body · 11-14-2009, 15:48

Quote:

Originally Posted by rtg143

That code means: No power to PCM pin 1 or bad PCM (processor)

Yes, or "511 -- Read Only Memory test failed", but does this mean a broken computer?

**Bert** · 11-14-2009, 17:02

Is there power at pin #1?

fox-body · 05-30-2010, 06:57

I gave this up, and stored the car for the winter. Now I am trying to solve the problem, but am stuck again. I still sporadic have the 511 code. Pin 1 seems to have 12.7 volt when power is off, 12.5 volt when power on engine not running and 14.6 volt when engine is running. From time to time I am not able to read fault codes. This is when "Check Engine" lamp is on all the time. Could it be that the self test never completes? Does anyone have any suggestions?

**Bert** · 05-30-2010, 09:42

You probably need a PCM. Here's a site with info on your system. Ford Fuel Injection

fox-body · 05-30-2010, 10:17

Do I have to use an EEC IV computer from a 3.8 Thunderbird, or is a computer from another car and engine combination compatible?

**Bert** · 05-30-2010, 10:43

They're very engine combination specific. Check that website, they have some info on that.

fox-body · 07-03-2010, 11:37

I replaced the eec iv and that solved the problem. It was a California computer in the car, but I replaced it with a non California computer and that swap seems to be ok.

**Bert** · 07-03-2010, 12:56

Glad you got it working. Thanks for the update.