Code 24???

[TommyL]

I took my 90 out for a spin yesterday after trying to erase the infl rest light grrrrrr. When I come to a stop, the idle goes way down, the "check engine light" and the "ride control light" come on. After driving for a bit to operating temp, the lights go out and all is well...car runs great.

I pulled the codes and have a code 24 "speed sensor". This sensor was replaced about 2 years ago and it might have 5,000 kms on the new one.

Any ideas as to what might be the cause of this code 24 other then the actual sensor itself ? Seems odd that it runs great after it gets to running temp and both lights go out.

As well, If I retrieve the codes and dissconnect the battery...will this erase the codes ? I would like to erase them and see if the code 24 comes back.

Thanks, Tom

[XfireZ51]

Originally Posted by TommyL

I took my 90 out for a spin yesterday after trying to erase the infl rest light grrrrrr. When I come to a stop, the idle goes way down, the "check engine light" and the "ride control light" come on. After driving for a bit to operating temp, the lights go out and all is well...car runs great.

I pulled the codes and have a code 24 "speed sensor". This sensor was replaced about 2 years ago and it might have 5,000 kms on the new one.

Any ideas as to what might be the cause of this code 24 other then the actual sensor itself ? Seems odd that it runs great after it gets to running temp and both lights go out.

As well, If I retrieve the codes and dissconnect the battery...will this erase the codes ? I would like to erase them and see if the code 24 comes back.

Thanks, Tom

Tom,

I would pull battery and see if codes come back. Altho the light goes out the code is still stored. If it comes back after pulling battery then I would go to FSM and follow the diagnostic tree for a Code 24.

[TommyL]

I have done this, could be one of many things and this is very intermitant. The speedo works for a bit after the car is warm, then reads "0" and the lights come on. I am thinking the darn speed sensor is pooched again but wow its not very old and has'nt got many miles on it.

[tomtom72]

Okay as Jeff (Sensi-san) hasn't seen this yet I'm gonna try & run something by you Tom. The VSS is a gear driven mini-alternator yielding A/C voltage, in my mind what's to break? The coil windings? the magnet? IMHO...not too likely...and since the FSM makes no mention of converting the v output to DC there is no rectifier bridge & diode trio to cook...or at least that's how I understand the FSM DTC24 page.

I'd check the simple things first like the connectors, the VSS plug first, try re-seating the EPROM(?), the 10 pin & 15 pin under the driver's hush panel. Maybe some contact spray cleaner & fresh di-electric grease? Check ECM pins A6 & A11 for dirt or damage(?) and A17 as it's the out to the CCM which eventually goes to the dash speedo display. Okay now I'm a bit lost at this point, sorry Tom.

This is a bit odd in that the DTC comes after warm-up....I'm stumped on that unless an ECM ground is vibrating loose or a wire is broken someplace...I hate to say this as it sounds silly. Jack up the rear, support the knuckle at level ride height w/more jack stands, start her up, get to temp, 1st gear engaged & let the clutch out and hook up a scanner and see if the scanner is getting a speed signal....but that really isn't for an "intermittent" code....

I hate electrical issues mostly because I stink at chasing them down, sorry.

[TommyL]

Thanks Tom...thats a great start for me. I will check all this out tomorrow (day off) and post the results. I, like youself, hate anything electrical...I can do almost anything work- wise on this car but electrical no so much.

Thanks again

[tomtom72]

Tom.

I was thinking that if you have the Helm FSM and the use of a scanner, you could hook up the scanner and just drive around with it and save the jacking up part of this mess.


Tom

God, I hate electrical issues!!!!!

[TommyL]

Anyone have the correct 1990 part number for the speed sensor?

[-=Jeff=-]

Originally Posted by TommyL

Anyone have the correct 1990 part number for the speed sensor?

25007308

Originally Posted by -=Jeff=-

25007308

Discontinued.

[-=Jeff=-]

Originally Posted by Jeffvette

Discontinued.