Mechanics

'98 - MIL DUE TO COMPUTER MALFUNCTION

1998 Toyota Rav4

Computer problem
1998 Toyota Rav4 4 cyl Two Wheel Drive Manual 110000 miles

My Rav4 failed smog test " due to a warning lamp failure" - apparently officialese for " Check Engine Light on". The code provided by the testing center was P0340 Camshaft Position Sensor CKT Malfunction. There was reason to believe the sensor may have been damaged when the water pump and timing belt were replaced earlier in the year. The light had been on intermittently ever since that work was done.

The mechanic I took the car to couldn't find any problems with the sensor. As he put it, they ruled everything it could be out, so all that was left was a problem with the computer. I was quoted a price of $2500, as well as being told that a) new computers were not available so it would have to be a rebuilt and b) only one company rebuilds computers and they do crappy work. He also mentioned that the replacement part would have to go to Toyota for programming.

Q1: If it was a problem with the computer, wouldn't there be more of an effect on the car's performance? (The car runs as well as one would expect of a car badly in need of a tune up; since it's a Toyota, that's still pretty good!)

Q2: Computers rarely malfunction due to hardware. Why can't I just have my current computer reprogrammed?

Q3: The Fasten Seatbelt light also comes on in error intermittently, sometimes in unison with the Check Engine light, sometimes in sequence. Doesn't that indicate a need to at least check that there isn't a short or something in the dash before jumping to a $2,500 conclusion?
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Progress
December 17, 2009.



I haven't had full time work since Sept 2007. I am getting by on a part time job and small amount of unemployment. I really wish I could afford to donate more.

Tiny
Progress
Dec 17, 2009.
Hi
All started with Timing belt you say mostlikely the signal plate on cam gear was bent causing code but no performance issues. The CMP and wirirng to ECM all check good and would if 1 tooth signal damaged it takes two drive cycles to set usually. When code is cleared doeas it set upon startup or after driving a bit?
Let me know
Thanks for donate

Docfixit
Dec 18, 2009.
After the code has been reset manually, the check engine light will stay off until triggered by high RPMs. I think that's what causes it to come back on, since it usually happens when I get on the freeway.

Once the light is on, it stays on for 5 to 10 miles (or less. I rarely drive anywhere since the tags are expired and I work from home) before it automatically resets.

Before I took it in, after the water pump/timing belt replacement, the light would go on and off at random, more or less, until it eventually came on and stayed on. Since the mechanic reset, it's gone back to being intermittent, as stated above.

Tiny
Progress
Dec 18, 2009.
Would check the sensor signs point to it

Docfixit
Dec 21, 2009.
I'm printing out the exchange to take with me to the mechanic. I am NOT going back to the mechanic that said it was the computer.

Thank you for the input. It seemed to me that the sensor was the culprit, given the history. What can you do when the mechanic refuses to listen to the history? Anyway, you guys were just the " back up" I needed.

Merry Christmas and Happy New Year!
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Tiny
Progress
Dec 21, 2009.
Would hope a good Tech would pick up on T belt replacement and MIL That one tooth signal is easily damaged.
Hope you get this resolved
MERRY CHRISTMAS

Docfixit
Dec 21, 2009.

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