sean882

My issues were years back and I no longer have the vehicle. However, I do recall that the culprit in my case was the TC Shift Solenoid in the transmission. It ohm'd out okay, but would stick when it got warm (after 20 minutes on the highway).

I eventually diagnosed it by wiring in a switch to each of the three solenoids to manually control the transmission. When giving it +12V directly (bypassing the brake pedal, NSS, Transmission Control Unit) and still having it kick out after a while on the highway, I was able to positively diagnose it. Cool byproduct was a switch that let me engage the TC while cruising below 45 and improve gas mileage. I forget where the wires were exactly, but I recall taking the center console apart and tracing it from the transmission itself. For some reason, yellow wire comes to mind.

slow_evo

Went through the TCM pinout troubleshooting steps and everything appears to be in spec except for the trans gear selector. TPS also is within spec.

I went for another test drive, and now the vehicle shifts like it is in limp mode and I have maybe 2 gears. Can't tell if I'm starting in 1st or 2nd (it feels like 1st), trans gear selector in D and it doesn't shift to the next gear until 3k rpm or so. After that shift, that's all I get. I'm at about 3.5-4K rpm at 60 mph, thinking it's giving me 1st gear when I'm stopped, then shifts to 3rd and stays there.

Still have P0700 and P0705. Is this looking like a NSS issue? I haven't had reverse lights (intermittent) since I bought it in 2011, but no problems starting in Park or Neutral.

Should I disconnect the TCM harness and see if it will give me all gears manually (except for 2nd)?

CCKen

What did the "trans gear selctor" test show? That's your TRS/NSS.

You could try the manual shift procedure but know that the TCM must be disconnected. Watch your RPM's when downsifting.

slow_evo

I believe in R I was getting about 3V, in D I got ~1V, and 3 and 2/1 was roughly the same. Nothing close to 12V.

I disconnected the TCM and shifted the gears manually. Everything appeared to be normal. I will take apart the NSS tomorrow and report back. Thanks for your help!

slow_evo

Update:

Removed/cleaned/adjusted the TRS (NSS) -- good as new. Here is what the status is:

- I now have reverse lights
- Test drive shows the trans is shifting 100% normal
- I now have TC lockup in 3rd and 4th
- When WOT I am given the correct gear given load and MPH

However, I am still throwing P0700 and P0705!! The battery was disconnected for 24hrs while I cleaned my NSS. Is there some other way to clear trans codes that I'm not aware of? The codes won't go away even though the vehicle is driving 100% normal. Any thoughts?

CCKen

Did you check the TRS/NSS voltages after you 'cleaned' the NSS? There could be a wiring issue between the TRS/NSS and the TCM connector.

If everything is okay, remove the CEL bulb. LOL

slow_evo

No, I haven't checked the TRS voltage at the TCM yet, I will do that next.

But you clear P07XX codes the same way as any other DTC, correct? Either with a scanner or by disconnecting the battery. The codes wouldn't be stored and saved after a battery pull, would they? Last time I checked, DTC(s) are written to RAM, so a power loss would clear the codes. Please correct me if I'm wrong.

Edit: Did some research, and it could be that my NSS is not adjusted correctly. Checking the voltage of the TRS at the TCM should tell me if that's the case or not. Also, even though I cleaned the NSS and it appears to be functioning correctly, I may need to replace with a new unit.

slow_evo

Final update:

After numerous attempts to adjust the NSS and verifying TRS voltage at the TCM, the P0700 and P0705 codes persisted. A test drive still verified the vehicle was operating/shifting normally.

Finally, I cleared the codes with a scanner and it has not returned after multiple test drives and on/off cycles.

Thanks again for everyone's help!

CobraMarty

What are you using to clear the codes?

CCKen

Good work, and thanks for the follow up.

slow_evo

Originally, I was disconnecting the battery leads and touching them together for 10 sec, then leaving the negative disconnected for 30 min or more. However, this wasn't clearing the p07xx codes for me. I finally cleared them with an Innova (sp?) scanner from O'reilly Auto Parts.