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Mar 6, 2009 | 03:50 PM

Toyota dad

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Joined: May 2006

Posts: 70

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Check Engine Light

I have a 95 4Runner with 3.0
Check engine light has a code 25 ( Lein fuel mixture)
takes anywhere from 50 to 100 miles of driving before it comes on -----
Any Ideas??

Mar 6, 2009 | 04:46 PM

mt_goat

Contributing Member

Joined: Nov 2002

Posts: 10,666

Likes: 5

From: Oklahoma State

I'd start by looking at the FSM for a 3.0. http://personal.utulsa.edu/~nathan-b...85diagnosi.pdf
From link above
For code 25:

Diagnosis

Quote:

(1) Heated oxygen sensor output is less than
0.45 V for at least 90 sacs. when heated
oxygen sensor is warmed up (racing at
2.000 rpm) and drive at 50 – 100 km/h

Trouble area

Quote:

• Engine ground bolt loose
• Open in E1 circuit
• Open in injector circuit
• Fuel line pressure (Injector
blockage, etc. )
• Open or short in heated
oxygen sensor circuit
• Heated oxygen sensor
• Ignition system
• Engine coolant temp. sensor
• Volume air flow meter (Air intake)
• ECM

See pages EG2-197 EG2-199

Mar 6, 2009 | 04:58 PM

mt_goat

Contributing Member

Joined: Nov 2002

Posts: 10,666

Likes: 5

From: Oklahoma State

Also note from the link above:

Quote:

(c) (2 trip detection logic)
The diagnostic trouble codes 21, 25, 26 and 71 are
used ”2 trip detection logic” is used. With this logic,
when a logic malfunction is first detected, the mal–
function is temporarily stored in the ECM memory. If
the same case is detected again during the second
drive test, this second detection causes the malfunc–
tion indicator lamp to light up.
The 2 trip repeats the same mode a 2nd time.
(However, the IG SW must be turned OFF between
the 1 st time and 2nd time).