Engine Coolant Sensor 1992 3vz engine ?

[Techventure]

I have a code 25 from my Engine Check light.

I want to test my ECT. In the Haynes manual it shows the ECT on the 3vz engine under a heat deflector and to get at it you remove 2 bolts..

I don't have a heat deflectorat this location as it's shown in the manual.

Did they change the design layout of this engine sometime in 1992 ?

I would appreciate someone telling me exactly where this sensor is and if i could even get a photo this sensor location it would be even better.

Thanks in advance.

[DFBonnett]

Looking at the manual it seems you have to remove the washer tank and the alternator belt to access it. Per the manual if sitting in a pan of water at 176F the resistance should be 1.48 to 1.58 k ohms.

[Toysrme]

You can't get to it because you didn't read it.
Code 25 is Air-Fuel ratio lean:
1) Vacuum leak
2) Test o2 sensor output, responce time, & warm-up time

Replace both your front & rear manifold o2 sensors. $30 generic splice in Bosch units work great.


Download the provided '93 Lexus ES 300 FSM that is in the stickied posts.

[Brian R.]

The OBDI codes for anyone who needs them:

[Brian R.]

[Brian R.]

[Brian R.]

[Brian R.]

[Brian R.]

Here's the page for OBD 25:

[Techventure]

Thank you to everyone that replied to my post. It sure is appreciated.

I have one other question:
The 02 sensor indicates a lean air/fuel ratio.....does this mean the ECM would increase the fuel ?
I believe this is what happenes because we are seeing an increase in gas used.
Just want to confirm this.

[Brian R.]

The lean fuel mixture condition means that the HO2 sensor is sending a lean fuel signal for some specific time period at idle under specific conditions. May not be under closed loop conditions, which are what is normally used when the sensor is at operating temperature.

If you have a malfunctioning HO2 sensor, then the ECM may prevent the engine from operating under closed-loop conditions, which are the best for mileage.