I can't seem to figure this one out. I have a code 24 which relates to the VSS circuit. I think the fact that I can't get .54V at the TPS at idle has everything to do with it. This code is supposed to set on deceleration which it does. Anyone have any experience with this code?

Chris

 

Still fighting a TPS voltage? That might solve both (all?) the problems.

Real times? That's about what I run - Bone stock LB9/TH700R4, 2.77 gears.

 

I've never heard of a relation between TPS voltage and setting a code 24. Check on a laptop or scan tool to check the vehicle speed that the ecm is reading. I bet you it says 0 mph.

 

Per the service manual, on a deceleration test, the code will set if for 4 seconds, an amount of correct throttle voltage is not sensed. To be honest with you, a code 24 can bet set about 6 different ways. WHAT A NIGHTMARE!!!!

 

Where in the service manual did you see that? I would like to read that.

To be honest with you, I drove daily around for about 5 weeks with the VSS disconnected after my T56 install, and I got a code 24 twice. Once during week 3, and once during week 5. I was surprised at that, and never really understood why it didn't happen more often.

 

go to the vin code f section. look up code 24 and check the section for diagnosis.

 

I just realized what a stupid question I asked. Thats what I get for trying to multitask one too many things.

 

No prob. Not stupid at all. maybe you asked because you wanted to go directly to the page so you can fix my car............

 

Well, I don't have an 89 manual. The closest I have to that is a 90 which uses a different ecm altogether. Things may or may not be different from yours, I don't know.

According to the 90 manual, 24 will set if the following conditions are met for atleast 4 seconds:

1. vehicle speed is 0 mph
2. vss output voltage to instrument panel is constant
3. engine speed is between 1400 and 3600 rpm
4. less than .10 volts above closed throttle
5. low load condition
6. not in park or neutral

If this is the same as what you are reading (it is possible that the 165 uses the same algorithm described above) then you can't have the TPS by itself cause a code 24.

It makes sense to be setting on decel, since conditions 3-6 will all be satisfied. Your problem will lie with condition 1 and 2, which are dependent on each other. For condition 1 to be satisfied, the ecm has to see 0 mph.

I still insist that you should check your vehicle speed while driving with a scan tool or laptop. I am fairly certain that its going to read 0 mph. It would probably be easier to check if its disconnected at the tranny first. If so, then thats your problem.

 

I know it won't trip by itself. I have other issues like my TCC does not lock up (will cause a 24, not listed on the 24 page but in the manual under TCC) and also that I can not get .54V at the TPS at idle position (no TPS code at start-up as I have it cranked all the way back to get .37V). I am thinking they must all be related to cause each others problems as it is possible. With my luck, it is 1 wire that is old or chewed through (had mice for awhile, that is what happens when the car gets stored in a barn for 6 years) that I can't see or get to without completely disassembling the whole damn car.

 

Even if you have other problems, your ecm is still almost certainly not getting a vss signal. So long as that happens, it doesn't matter what you do with the TPS or TCC, conditions 1 and 2 from the list will be satisfied always.

Don't look into things too far. Start with the basics. Check that the vss connector is plugged in at the tranny, and then check the vehicle speed while moving with a scan tool or laptop.

 

My VSS is not at the tailshaft as I have a mechanical speedo. The VSS is mounted to the back of the speedo and uses a buffer which is under the dash next to the ECM (that is what the manual says anyway). My speedo works but it obviously is not getting the pulses to the ECM from either the VSS itself or the buffer. I also have this issue of the car not idling correct, not being able to set minimum standards for the TPS and IAC as well as it shuts off when I drive it after I get off the gas. Add to that my tach bounces and the car misses at a certain part in the travel of the gas pedal.


Should I just burn this thing or what?

Oh yeah, I connected the Actron 9145 scanner to my car and it will not read. Someone else had that issue, sent the scanner back and Actron gave them an entirely different brand scanner that works. I bought a laptop to connect via WinALDL so when I finally get a cable, we will see what is what.

Chris