99' 4Runner ECU check light issues
#1
99' 4Runner ECU check light issues
I tired to search for help on this topic but i' not really sure what to search for.....
My 1999 SR5 4x2 4Runner threw up a check light the other day, a quick scan showed that the left bank of the engine was running lean, we reset it hoping that it was a one-time error but it came back the following week. The O2 sensor is ok and it seems like the ECU is what is giving the problem. The ECU is constantly getting the "high" voltage from the O2 which is giving the error but a replacement of the O2 didn't fix the problem, my friend's shop is thinking it may be a bad ECU but they don't want to get another one without being sure because of the high cost of a new ECU. Also if I replace the ECU will it affect anything else in my truck? Is the odometer mileage stored in the ECU also? can anyone help?!!?
thanks!
My 1999 SR5 4x2 4Runner threw up a check light the other day, a quick scan showed that the left bank of the engine was running lean, we reset it hoping that it was a one-time error but it came back the following week. The O2 sensor is ok and it seems like the ECU is what is giving the problem. The ECU is constantly getting the "high" voltage from the O2 which is giving the error but a replacement of the O2 didn't fix the problem, my friend's shop is thinking it may be a bad ECU but they don't want to get another one without being sure because of the high cost of a new ECU. Also if I replace the ECU will it affect anything else in my truck? Is the odometer mileage stored in the ECU also? can anyone help?!!?
thanks!
#2
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Which code did you get? P0171 ? Try cleaning the MAF. Search for it, you'll find a write up. Sometimes it works. It did on mine ('99 SR5 4x4)... Particularly if you have an oil type air filter. Also, the MAF may be bad, but try cleaning it first. Hey, can't hurt and all it'll cost is a can of electrical contact cleaner.
Good luck.
Good luck.
#4
Contributing Member
Which code did you get? P0171 ? Try cleaning the MAF. Search for it, you'll find a write up. Sometimes it works. It did on mine ('99 SR5 4x4)... Particularly if you have an oil type air filter. Also, the MAF may be bad, but try cleaning it first. Hey, can't hurt and all it'll cost is a can of electrical contact cleaner.
Good luck.
Good luck.
Last edited by MTL_4runner; 11-05-2006 at 03:22 PM.
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