2001 Jaguar S-Type • 30,000 miles

How do you check the powertrain control module to see if it needs replacing
January 11, 2013.

You eliminate all the other possibilities. Engine Computers are normally the least suspect item but the first thing do-it-yourselfers jump on because they aren't doing what they're expected to do. Most troubleshooting procedures involve a diagnostic guide with pages of troubleshooting steps covering just one symptom or fault code that end with finding the break in a wire or replacing a defective sensor. Most of the time you need a scanner to command certain functions on and off to test the computer's ability to process incoming information and to act on it. When we read that someone replaced a bunch of parts including a computer, 95 percent of the time the computer didn't solve the problem and just added more variables to the problem. The exception is older GM vehicles. They did have a lot of computer trouble. Older mechanics who experienced those common failures assume today that's still a big problem so the first thing they want to try is the computer.

Jan 11, 2013.