Successful repair of 2002 Sentra ECM

[sbjohnston]

A few weeks ago my 2002 Nissan Sentra started exhibiting erratic and high idle speed, crazy transmission shift points, frequent inability to use a code reader to talk to the computer, and error codes related to the throttle position sensor. After much frustration I realized that this pattern of symptoms pointed to a bad engine control module (ECM). Nearly ten years ago Nissan acknowledged a series of ECM failures with a recall. They traced the failure to resistors on the ECM circuit board that had gone bad due to corrosive fumes from the ECM cover coating.

Unable to find a reasonably-priced replacement ECM I decided to open mine up and do some troubleshooting. I pulled it out, exposed both sides of the circuit board, and inspected it with a magnifier. No trouble was visible to the eye, so I checked each of the many resistors on the board with an autoranging ohmmeter. I found three bad resistors: R005, R223, and R709. All three had resistance much much higher than the marked value. I carefully unsoldered the surface-mount resistors from the board and tack-soldered 1/4-watt replacements in place.

Reinstalled the board in the housing and put it all back in the vehicle. Initially the idle speed was high, but steady. I warmed up the engine, then performed the throttle position relearning procedure and it settled down nicely to s smooth 700 rpm. Schweet! My good results have continued for several drives so I think I've done it.

Steve

[06_blkout]

Very cool! You're a brave man lol.

[jdansmith]

^ agreed, glad it worked out for you. Check back in a few weeks and let us know if it hold up.