Code 629

[uberninja]

Today I ended up pulling codes on the Ex and the only one I'm getting currently is a 629. Which is the CC Solenoid Circuit Failure on the A4LD. What I've been noticing is that the RPMs staying around 2.8k at 60mph and about 3k at 75mph. Is it normal for it to be this high or is the torque converter not engaging? I'll check the door code for the gearing option. I know its an LSD. My mileage appears to be down, but I'm not sure if that is from the cold winter days or the larger alternator. I'm not stalling at stops, however my cruise control no longer works. Any ideas of where to start?

I'm thinking of replacing the TPS first because when my radiator cracked and the fluid got sprayed around, my speedometer was acting up (bouncing at 85 when I was clearly doing 25). But it seems to give me accurate readings the rest of the time. Could it be sending a bad signal somewhere? My cruise control has been intermittent since around that time, but would be hard to be sure as I rarely use the cruise control on my daily winter commutes. The buttons seemed to work for a while, but then I was only able to on the system and get acceleration if I held in the set button, but then it wouldn't hold the speed I selected. Now I don't get anything at all from the buttons. I want to check the vacuum dump switch on the brake pedal at some point as well. I know there is a cruise control amplifier that could be replaced as well. I just don't know if I have two separate issues or one lumped issue.

Thanks in advance!

 

[natenkiki2004]

TPS doesn't have anything to do with the speedometer. For what it's worth, none of the sensors or electronics under the hood should be bothered by water.

I made a video about the solenoids and gear shifts, it's kind of a crappy video and I screw up in it but there is some valuable info regarding testing:

 

[uberninja]

TPS doesn't have anything to do with the speedometer. For what it's worth, none of the sensors or electronics under the hood should be bothered by water.

I made a video about the solenoids and gear shifts, it's kind of a crappy video and I screw up in it but there is some valuable info regarding testing:

So would you say I'm chasing down two different issues then? Maybe a VSS related issue? Any idea what would've caused the speedo to bounce like that then?

Great vid by the way. I'll be sure to look into that kind of testing soon.

 

[natenkiki2004]

The speedometer is cable driven, no electronics. Any issue with it is either a sticky cable, worn gear or issues in the cluster itself. You're probably better off living with it to be honest.

The vehicle speed sensor is more used for things like shifting 3-4, TCC lockup and the 4x4 computer (to engage LOW when not moving).

 

[uberninja]

Alright, thanks for the input Nate. I can live with it, tranny shifts smooth otherwise. Just went for a late night drive down the highway and saw 60 at 2200rpm. Can I explain it? Absolutely not. Still no cruise control though. Guess I'll comb through more pages to see if anything pops up.

 

[uberninja]

The speedometer is cable driven, no electronics. Any issue with it is either a sticky cable, worn gear or issues in the cluster itself. You're probably better off living with it to be honest.

The vehicle speed sensor is more used for things like shifting 3-4, TCC lockup and the 4x4 computer (to engage LOW when not moving).

Nate, solved the problem with the cruise control. It ended up being the vacuum dump on the brake pedal. I managed to readjust it and I haven't had an issue since. I had no idea what it looked like. I'll try and post a picture somewhere so people know what exactly they should be looking for.

As for the 3-4 shifting, I haven't had an issue since I took my truck in to have a tranny leak checked out. Bad hose fitting at the radiator. It sits closer to 2600rpm at 70. My fuel mileage has returned, 17mpg over 200miles at 70 is a win in my book.