speed sensor circuit??

purekoryo · 01-07-2006, 08:23 AM

I have a 1998 Jeep Cherokee Laredo 5.2L. I'm getting a check engine light for speed sensor circuit. I've replaced the speed sensor and transmission relay, but still I have the engine light. The car's shift point between 1 and 2nd gear is longer than usual, especially during cold start (changes to 2nd gear at about 4 k rpm!) Just recently, the car has also been stalling when coming to a stop. I also have to add the tranmission fluid more often. I use dexron III for tranny fluid.

Does anyone know how to fix this problem? is there another sensor I should replace? Are there two speed sensors i need to replace?

any help would be appreciated!

jeepholic · 01-07-2006, 08:41 AM

It sounds like the sensor is working and is telling you about a problem Changing the sensor won't fix the problem.
That code has many different forms from showing no voltage to intermitent voltage and temprature. I would get it scanned with a good scanner like a Snap-on that gives more detailed code info.
The Jeep should not change gears at 4k. I bet that scares the beejeezus out of you, reving that high and dumping into 2nd.
While most likely the code is the problem the high rpm thing could be a TPS (search TPS*).

jeepholic · 01-07-2006, 08:44 AM

You need to find the tranny leak. Trannys don't "use" fluid like an engine uses oil, it must be leaking. The idle stalling is also related to the TPS and IAC, both on the throttle body and both should be cleaned at least every year with your throttle body.

purekoryo · 01-07-2006, 10:05 AM

Quote:

Originally Posted by jeepholic

You need to find the tranny leak. Trannys don't "use" fluid like an engine uses oil, it must be leaking. The idle stalling is also related to the TPS and IAC, both on the throttle body and both should be cleaned at least every year with your throttle body.

thanks for the reply.
got a question though. if its the throttle position sensor, wouldnt it show up on the check engine light code?

btw, here are two pictures of the speed sensor. The furthest one in the back is the one i replaced; however, I want to askwhat the furthest one in the front is?
http://pg.photos.yahoo.com/ph/pureko...bum?.dir=/a1d4

the car only has about 75k milies on it.

brandoncrone · 01-07-2006, 10:10 AM

Which speed sensor have you replaced. THere is one on the transmission and one on the transfer case.

Jayrod586 · 01-07-2006, 10:16 AM

I think you also have to disconnect the battery for a minute to reset it if I remember corectly. I replaced the OSS last year too.

jeepholic · 01-07-2006, 10:17 AM

The TPS is easy enough to check with instructions on here. So code or not, just check it and clean your intake.

I don't know that much about the speed sensor sorry, one of the guys here will help today.
My point was that I have seen in SOME cases a sensor tell the OBD of a problem and the person changes the sensor.
As an example, a customer asked me to change his knock sensor in a foriegn truck. He went to the dealer and bought the new knock sensor. I got to his house and started the truck and the engine knocked very loud, like a bad rod. The knock sensor went off and did it's job but the owner thought the problem was the sensor.

In another example a code for an O2 sensor could mean to change the sensor.

Just items to think about until the guys in the know respond.

purekoryo · 01-07-2006, 10:51 AM

Quote:

Originally Posted by brandoncrone

Which speed sensor have you replaced. THere is one on the transmission and one on the transfer case.

i changed the one on the transfer case, which is the one furthest to the right if you are looking from the driver's side, which is also the one with the bolt.

purekoryo · 01-07-2006, 10:53 AM

Quote:

Originally Posted by jeepholic

The TPS is easy enough to check with instructions on here. So code or not, just check it and clean your intake.

I don't know that much about the speed sensor sorry, one of the guys here will help today.
My point was that I have seen in SOME cases a sensor tell the OBD of a problem and the person changes the sensor.
As an example, a customer asked me to change his knock sensor in a foriegn truck. He went to the dealer and bought the new knock sensor. I got to his house and started the truck and the engine knocked very loud, like a bad rod. The knock sensor went off and did it's job but the owner thought the problem was the sensor.

In another example a code for an O2 sensor could mean to change the sensor.

Just items to think about until the guys in the know respond.

ill go ahead and check the tps as well. thanks for the tip

purekoryo · 01-07-2006, 10:54 AM

is the sensor on the tranmission also a speed sensor? if so, do you guys know where i can find the part#? i checked advanceauto online, and they only came up with one speed sensor.

thanks

purekoryo · 01-08-2006, 08:02 AM

anyone?...please?

Robinton · 01-08-2006, 12:35 PM

Had same problem with my 99. codes said vss, replaced one on transmission (the one in front) and the problem was solved.

jdk3034 · 01-08-2006, 01:30 PM

Dexron III? You shouldn't use that in a Jeep transmission. You need either ATF+3 or +4.

purekoryo · 01-08-2006, 04:32 PM

Quote:

Originally Posted by Robinton

Had same problem with my 99. codes said vss, replaced one on transmission (the one in front) and the problem was solved.

did you get it at regular auto parts store or at a dealership? because i only saw one speed sensor at the parts store.

purekoryo · 01-08-2006, 04:33 PM

Quote:

Originally Posted by jdk3034

Dexron III? You shouldn't use that in a Jeep transmission. You need either ATF+3 or +4.

oops, ill get that flushed out and put the atf+3 or +4 after i get the leak fixed.