12 replies to this topic

[cal198]

Hey guys, i'm chasing a speed sensor issue. Since i've changed my gearbox from GSR to Evo3 my speedo is now reading incorrectly, as expected. What I didn't expect was that it would also throw a Speedo sensor (I didn't even know they had speed sensors until I looked) and secondly, that said speed sensor would throw the computer into factory limp mode (I'm assuming...?)

 

Is this correct that this speed sensor is throwing the ECU into limp mode or am I chasing another dead end?

[evo-gsr]

I doubt the speed sensor is causing that issue.

[jack be nimble]

What code is it throwing?

[cal198]

I think its 21? Speed sensor fault. Old school flash codes

[cal198]

No other codes noted

[leadfoot]

21 is coolant temp sensor

[blackvr]

Speed sensor wont create a limp home mode...

[cal198]

Thanks guys. Yeah sorry, I'll double check the flash codes but I'm certain the code I looked up was a speed sensor fault, not sure on the flash number but I'll check again tomorrow

[leadfoot]

ecu = 1l

02 sensor = 1l 1s

afm = 1l 2s

IAT (contained in afm) = 1l 3s

tps = 1l 4s

colant temp = 2l 1s

crank angle = 2l 2s

tdc sensor (in cas) = 2l 3s

VSS = 2l 4s

barometric presure sensor (also in AFM) 2l 5s

detonation sensor = 3l 1s

ignition timing adjust sensor = 3l 6s

faulty injector 4l 4s

all normal 7s

[cal198]

Only code coming up is 24 - VSS

 

I have only a basic understanding on these ECU's. Is there somewhere I can look for Sensor values and check on the ecu? like TPS voltage etc.

 

Or does anybody have a good understanding as to other reasons it can run a limp mode?

[DOUGMO]

correct me if im wrong but the ecu gets the speed signal from the back of the instrument cluster?

 

as the speedo is cable driven

[evo-gsr]

Thats right George....in my knowledge anyway.

[cal198]

Yes the sensor runs in the back of the dash and also compares with abs sensors as well. At a certain ratio it should be something like 4 speed sensor revolutions to every one wheel revolution or vise versa, I always forget.