I want to replace the ECM on my Ford Focus. I found the exact number unit in a salvage yard. Will it work?

Question

by just plugging it in, or will it have to be reprogrammed? Also, will the ignition keys work? It has 160K with multiple symptoms and no codes come up. Rough idle, poor mileage, engine miss and the speedometer pegs over to !40. All intermitently, so I'm guessing the ECM might be faulty.

Answer 1

There is something else going on, It is extremely rare that a ECM is faulty, and I do mean EXTREMELY rare. Your best bet is let someone look at it that knows what they are doing. You may found a ECM with the same number, but I can give you a sure guarantee that the calibration is different, and no, it cannot be reprogrammed, plus, getting one from a junkyard, you do not know what you are getting. My best advice to you is to leave it alone and let someone that has the knowledge to diagnose your problems.

Answer 2

I had the same problem with an 02 focus, the ecm would fire intermittantly to cyls 1@4 from the primary side( checked this with inductive timing line and computor compatable test lite), also when the miss occured the speedo would jump to 140, found oil in cylinders contaminating the plug wires, also excessive heat on the primary harness to the coil pak, fixed the oil leakv.c. seal/gasket, and repaired blk/orn ecm trigger wire by egr pipe, all good now! ase master 39 yrs sorry guys G.M. drivablity specialist.

Answer 3

I am not an expert. I am a ford owner.
First
On
Royal
Dynasty

The ECM is not your prob!

1.) Check your plugs and Wires if they are not Motorcraft trash them this is one of your prob.
** Engine Miss, bad gas mileage, rough idle

2.) Check you air filter, PCV Valve make sure they are good.
A dirty air filter will cause bad gas mileage

3.) Check your tire pressure. This might sound silly but it helps

4.) Treat your Gas with Lucas Gas Treatment