1993 850 I think ECU reset fixed No start for no reason

[prjones88]

This December 2016, I again experienced the proverbial "no start for no apparent reason" syndrome on my 1993 850 Volvo. This happens approximately once or twice a year sometimes not even that often. The car will be running fine and out of the blue, you go to start the car, hear the fuel pump running, turn the key and the starter turns over but the car refuses ignition or to run. There appears to be no obvious symptom prior that would explain why this happens nor does the problem set any codes, to help define a possible solution or begin diagnosis of this problem. Many have traced this to a defective fuel relay and temporarily corrected using the short wire across the relay method; others have traced it to problems with the cam position sensor or crank sensor. I have personally traced it one time to a defective ignition coil. The problem I had recently was solved by disconnecting the battery, cleaning the terminals and re-attaching the cables. I believe disconnecting the battery caused either the ignition or fuel ECU module to reset and the car once again was running fine. Go figure.

[beigg]

The problem I had recently was solved by disconnecting the battery, cleaning the terminals and re-attaching the cables. I believe disconnecting the battery caused either the ignition or fuel ECU module to reset and the car once again was running fine. Go figure.

I'd plan ahead; Replace those battery cables and both sides of each cable for its terminals.