Is there a common cause and resolution for DTC25
11-11-2009, 07:22 AM
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Is there a common cause and resolution for DTC25
I am getting code 25. I've cleared it and it comes back. It doesn't seem to affect performance or drivability, but i want it to go away for good. is there an easy or common fix to this prob?
1995 4Runner 3.0
1995 4Runner 3.0
11-11-2009, 07:27 AM
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It means that:
... O2 sensor is continually reading lean. Could be bad O2 sensor.
... the ECU has enriched it's "trim" adjustment and the O2 still reads lean. Could be vacuum leaks, exhaust leak(s) between the engine and the O2 sensor, maladjusted throttle position sensor, coolant sensor malfunctioning or possible the vafm. Vac and exhaust leaks should be easy enough to locate. Any of the sensors the ECU uses may be just slightly out of spec but not far enough out to trip a code of their own and since the O2 is like the final indicator of mixture, anything that affects the mixture can trip conditions with it.
... O2 sensor is continually reading lean. Could be bad O2 sensor.
... the ECU has enriched it's "trim" adjustment and the O2 still reads lean. Could be vacuum leaks, exhaust leak(s) between the engine and the O2 sensor, maladjusted throttle position sensor, coolant sensor malfunctioning or possible the vafm. Vac and exhaust leaks should be easy enough to locate. Any of the sensors the ECU uses may be just slightly out of spec but not far enough out to trip a code of their own and since the O2 is like the final indicator of mixture, anything that affects the mixture can trip conditions with it.
11-11-2009, 07:43 AM
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It means that:
... O2 sensor is continually reading lean. Could be bad O2 sensor.
... the ECU has enriched it's "trim" adjustment and the O2 still reads lean. Could be vacuum leaks, exhaust leak(s) between the engine and the O2 sensor, maladjusted throttle position sensor, coolant sensor malfunctioning or possible the vafm. Vac and exhaust leaks should be easy enough to locate. Any of the sensors the ECU uses may be just slightly out of spec but not far enough out to trip a code of their own and since the O2 is like the final indicator of mixture, anything that affects the mixture can trip conditions with it.
... O2 sensor is continually reading lean. Could be bad O2 sensor.
... the ECU has enriched it's "trim" adjustment and the O2 still reads lean. Could be vacuum leaks, exhaust leak(s) between the engine and the O2 sensor, maladjusted throttle position sensor, coolant sensor malfunctioning or possible the vafm. Vac and exhaust leaks should be easy enough to locate. Any of the sensors the ECU uses may be just slightly out of spec but not far enough out to trip a code of their own and since the O2 is like the final indicator of mixture, anything that affects the mixture can trip conditions with it.
Thanks for the suggestions. I've tried a different vafm already and just replaced igniter as well (regarding a different code i was getting). I've checked all the intake hoses for leaks or loose connections. I'm thinking about replacing the o2 sensor. Ebay has them for really cheap, but is it a bad idea to go w/ something so cheap?
here is a link for reference. http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT
maybe i'll just try an o2 sensor from my 89 4runner before purchasing.
what is the best way to find a leak in the vacuum and exhaust?
I live in CA as well, not sure if that makes any difference is the cause.
Last edited by easy-3vze; 11-11-2009 at 07:44 AM.
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