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Honda-Man, Honda Mechanic
Category: Honda
Satisfied Customers: 3079
Experience:  I have an Associates Degree in Automotive. 10 Years experience on all makes and models. 20 Years Honda only including factory training. Over 30 years total.
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Second opinion] - 2001 civic 1.7 manual trans. keeps blowing

Customer Question

Second opinion] - 2001 civic 1.7 manual trans. keeps blowing computers?
JA: Are you fixing your Civic yourself? What have you tried so far?
Customer: brought used computer from junk yard had it flashed, engine ran fine for about half a day same problem engine goes into limp mode, unable to commuicate with ecm with scan tool.
JA: How many miles are on the car? Is it an automatic or a manual transmission?
Customer: 150,000 manual
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 10 months ago.
Category: Honda
Expert:  Honda-Man replied 10 months ago.

Thank you for taking time to ask your Honda-Acura question on JustAnswer. My name is ***** ***** online handle is Honda-Man I will be assisting you.

Expert:  Honda-Man replied 10 months ago.

The most common cause of your problem is voltage spikes. By far the most common cause is loose or improperly tightened alternator bolts. This causes a poor ground between the alternator case and engine. As the alternator ground resistance changes the output voltage spikes frying the ECM/PCM. I have included 2 articles on this exact subject for you to read. Seen this in the shop and here online many times. Usually happens after replacing a belt, timing belt or the alternator. Bolts get left loose or improperly tightened. Also make sure there is a solid ground cable to the body and engine. Check the highlighted ground locations in the images.

Please reply if you need more help so we can continue this conversation at no extra charge. This does not have to be my only answer. If you are satisfied with my service, please rate at the top of the page before exiting the site. Rating does not close out your question or cost extra. Remember, sometimes it is difficult to completely diagnose your vehicle without being there, I will try to give you the best answer possible.

Thank you!