QuestionQUESTION: I have a 1986 Toyota pickup with a 22RE. The engine check light stays on so I did the jumper wire into the socket next to the coil and got the code on the dash light/ engine check light. I got 2 flashes then 1 flash. What could it be ??
ANSWER: The code 21 indicates an oxygen sensor failure located in front of the catalyst, replacing this O2 sensor normally fixes this condition if the engine doesn't have a misfire or other mechanical problem that could affect air/fuel mixture.
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QUESTION: even though my Haynes manual says for an 88 & up its an o2 sensor but 84-86 1 = no problem 2= an air intake issue
ANSWER: Diagnostic trouble codes for the early model EFI engines are always a two digit code, if the 2 is first and then the 1 it means it's a code 21, toyota has never used a single digit code, in case the light flashes on/off with no pauses it means there is no trouble code and the system is normal.
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QUESTION: OK, replaced the o2 sensor and the engine check light still comes on. Same code also. What else could it be ? I noticed the EFI relay down @ drivers side kick panel fuse box gets warm to hot by the touch. It looks like the original. Could that be it ?
AnswerNotice that in my first answer I stated that "if the engine did not have a misfire or other mechanical problem" that the O2 sensor is the most likely cause, since the sensor did not fix the problem you may have to go a little farther with your diagnosis because if the rich/lean fuel mixture is caused by an engine problem it will turn the check engine light on with an O2 sensor code, this could be due to an intake air leak, a leaking valve or other cause of compression loss or a misfiring cylinder or even a blown headgasket.
