Hey gang,

Anyone can share some info why my TRAC light comes on about 5 minutes after driving.

 

Older 1UZ-FE engines will have their main O2 sensors go. it's about $100 for the part @ the dealership. According to the techs, it's a pain to replace unless you have access to a lift.


To confirm that it is the o2 sensor, try pulling the check engine light code.


Here's someone elses post on this. The techs @ the dealership just short out two pins under the hood, and check the lights.


I have a code 25 (check engine light blinks 2x, pauses the blinks 5x... repeats)

When my check engine light comes on, the trac goes off too.



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DIAG. TROUBLE CODE
25/26 FOR 93 SC400

There is a DLC1 under the hood. It’s a small black box with a cap covered located at the front left of the engine.
1. Warm up the engine to normal operating temperature
2. Connect terminal TE1 and E1 with a paper clip.
3. With a voltmeter, connect positive probe to terminal VF1, VF2 and negative probe to terminal E1 of the DLC1. Probe VF1 and E1 then VF2 and E1.
4. Warm up the oxygen sensor by running engine at 2,500 rpm for about 2 minutes.
5. Then, maintain engine at 2,500 rpm, count how many times needle of volt meter fluctuates between 0 and 5 V.
Results
Needle fluctuates 8 times OK
Continue at 0 V NG type I
Continue at 5V NG type II

Check Voltage between terminals OX1, OX2 and E1 of DLC1.

NG type I
1. Engine still at normal operating temperature.
2. Measure voltage between terminal OX1, OX2 and E1 of DLC1 when engine suddenly race to full throttle.
3. The voltage should be 0.5 V or higher at least once----OK
Need to perform this inspection within 1 sec.

NG type II

There are too much in formation to type in here. Need the whole repair manual.

There is another check for oxygen sensor

1. Start engine and warm up
2. After engine is warm up, let it idle for 3 min.
3. With A/C ON and trans. In D position (O/D ON) perform gradual acceleration within the range 1,300-1,700 rpm (centered around 1,500 rpm)
(Take care that the engine speed does not fall below 1,200 rpm when shifting. Gradually depress the accelerator pedal and kept it steady so that engine breaking does not occur.)
4. Maintain the vehicle speed at 40-50 mph (64-80 km/h)
5. keep the vehicle running for 1-2 min. after starting acceration.

HINT: If a malfunction exists, the malfunction indicator lamp will light up after approximately 60 sec. from start of acceleration.

NOTICE: If the conditions in this test are not strictly follow. Detection of malfunction will not be possible.

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John