hi guys

here is a question.

the saturday i was looking for a problem with my speedometer, it messuring like 40mph in idle.

when I was looking the speed sensor and disconnect it the CEL light on my car dont turn on, is that correct?

my CEL i working well, if i disconnect any other sensor it light on correctly, any suggestion?

 

The vehicle may have to be moving to set off a CEL.

 

Disconnnect the VSS and go drive around. The CEL will eventually come on.

 

ok i will check that, but why if i disconnect the TPS, IAT, EACV or even the ECT the CEL comes on inmediatly?

 

The ECU is looking for a 0-5v pulse from the VSS. The VSS won't send the 0-5v pulse unless
the wheels are turning.

I've dealt with a couple of bad (OBDI) VSS, and the both wouldn't set off a CEL until a the
car was driven for quite a while.

 

did you ever figure this problem out? Im having the same problem now at idle my speedometer is reading 40mph

 

If the odometer works, your speedometer is most likely bad.

 

i replace the gauge assambly, now the speed meter is messure correct, thx!