Code 42 - Vehicule Speed Sensor

[Quartz7]

Hi, I have a 1991 jdm gt4. Each time I get on the highway (and only when I'm over 100km) the check engine light goes on (code 42.)

I was about to get the sensor replaced, but my speedometer works just fine... in fact the whole car runs great. I erased the code from the ECU but it keeps getting back (each time I get on the highway.)

Does anyone knows the part number for that sensor and where it is located on the car. Also I need to find a place where I can order this part online.

Your help would be more than appreciated !!!

Any idea of what else it could be (anyone had this problem before ?)

[Doctor J]

If your car has ECT a/t try to find if this code is stored in a/t computer's memory.
the sensor on 90 celica is located near speedometer head , one end connected to the ground and other end is connected to the engine and ECT computers' terminals.
the sensor itself is the reed switch [looks like glass tube about 3mm dia ,20 mmlong

[Quartz7]

Thanks a lot for your help Doctor J, your reply was very relevant but I forgot to precise that I have a manual transmission.

Here is what I've found on code 42:

(M/T)
No pulse is input from the speed sensor (SP1) bult into the meter during input of a 4-pulse signal from the vehicle speed sensor (SP2) on the transmission


I also understand that there is 4 ABS speed sensors located next to each wheels. Witch sensor should I check ? SP1, SP2...or the 4 ABS speed sensors. (As you can see I'm far from an expert !)

Another precision that might help the diagnostic... that check engine light goes on at 102km/h .... not at 100... not at 90, only when I accelerate from 100 to 102 !

Thanks in advance for anyone who has an idea to share !

[jlspec]

Follow your speado cable to the transmission, there you will find what your looking for as it will have a wire connection on it. Note it's going to be a pain as its very a tight area and hard to see part on our cars, Good luck. The part can be order from www.1sttoyotaparts.com, but I don't have the part number. Go to your local toyota dealer and have them look it up then get the part number and then buy it from website.

[Quartz7]

Had a bit of time this weekend. I took a look at the sensor (part No 83181-20040.) It seems ok... no broken wire on connector...and when I spin it with a drill I get a speed reading on the dash. I guess I'll need to order a new sensor to get rid of the check engine. Its sad to pay about 200$ for a sensor when there is absolutely nothing wrong wit the car except that orange light !

If someone has another idea before I order the sensor pls let me know.

Thanks for your help !