Torque Converter/cruise control/lamp out warning - Related?

[GCK]

My cruise control started dropping out regularly. I can reset it and it works for a while and drops out again. Recently my torque converter will not unlock and just like some others have written the truck shakes violently when stopping and sometimes will kill the engine. It does seem to still shift fine and I do not experience this problem all the time. Now I am getting a "lamp out" warning occasionally. Could all of these problems be related? This truck is a 03 model with 212,000 miles I have owned since new. Any suggestions would be appreciated! Thanks

 

[rbattelle]

It's possible they're related. There's a TSB that describes corrosion on a PCM connector that can cause all sorts of oddball problems.

If that's not it, I wonder if there's a problem with your Accelerator Pedal Position Sensor (APPS), which on your vehicle should be located on the intake manifold just in front of the intake horn (big black box). I'm not sure whether a faulty APPS will cause a torque converter lockup problem on these trucks - someone who knows will hopefully chime in here.

Cruise control problems could also be explained by a vacuum problem - either with the pump or the plumbing.

The "lamp out" warning could very well be a problem with either one of your light bulbs or a lamp connector. The taillights are notorious for corroded connector problems, so you might look there. Also, many of us have found that a lamp can set off the "lamp out" indicator intermittently even though it still illuminates like a normal bulb!

If it were me, I'd begin by checking my PCM connectors. Then move on to check the vacuum system for the cruise control. Then the APPS.

Ryan

 

[GCK]

Thanks rbattelle,

I will pull the battery and see if the vacum lines are okay but I was thinking on the 03 there are no vacuum lines. I thought it was all electronic. That led me to think the APPS might be involved on both items. I will get into that too to see if the connections look okay and maybe do some cleaning of the connections. I have noticed the battery on the passenger side appears damp on top and a little corrosion on one connector. It still has the original batteries so after almost 6 years I might go ahead and replace those too. I am wondering if a bad ground at that battery may have something to do with my problems.

Thanks again for the response and help!

 

[rbattelle]

I thought it was all electronic. That led me to think the APPS might be involved on both items.

Up until 2004. 5 - I believe - trucks with automatic transmissions had a vacuum pump to run the cruise control. Pretty silly if you ask me - sort of an unfortunate carryover from previous generations.



Certainly the APPS is common to both the cruise control and the transmission, so you're quite right to suspect it. But it's worth checking out the vacuum system while you're at it.



Ryan

 

[GCK]

Just a follow-up on this problem. I was reading my old strings and noticed this one.
Torque converter turned out to be bad. Transmission rebuild and new converter fixed that. The cruise control turned out to be caused by the neutral switch on the transmission! Vibration was making the CC see neutral and shutting down! The shop adjusted the switch and the problem went away!