Hi,
I am new to this forum and am hoping someone can help me out.

We have a 2008 Dodge Ram 1500 that stalls randomly. No lights come on and it doesn't throw any codes. It is a 4.7L V8 engine.

I first brought the car to a mechanic and he had it for a week. Didn't know what was wrong so gave it back. Next, I brought it to Carmax and they had it for nearly 2 weeks (we bought the truck there 6 months ago). They thought TIP Modulator and replaced it. Nope, wasn't that. It finally ended up at the dealer. They said to start at the bottom and replace spark plugs. I never bought that one, but had them replace and two days later the truck stalled.
The dealer now wants to replace coils one by one which is a time consuming, lengthy process, not to mention the cost and even that is no guarantee. Bottom line they don't know what is wrong with the truck since it's not throwing codes. Well there was a history code(?) P0688. I don't know what a history code is or means, but they did some research and are going off of their dodge library.

I went to JustAnswer online and it was mentioned to have the dealer replace the crankshaft position sensor and/or camshaft position sensor.

The dealer never mentioned either of these sensors as an option.

What do you all think? The truck goes in on Monday.

Thanks,
Nancy

 

My manual says that code P0688 is : Automatic Shut Down (ASD) sense circuit, low voltage

I can't claim to know what that is but it may give you something to look up,and I am sure some of the guys here will be able to give you more info.
Good luck!

 

Yes, the dealer gave me a bunch of paperwork and it said to replace spark plugs which we did and it didn't work. Now it says to replace the coils one by one. Ugh - this is horrible and would take forever. They told me you replace one coil with the new one and test for the condition to occur (which can take days) and if that doesn't work then move the coil around to each of the different cylinders until the condition is no longer present (if this is the case).

Not sure what to do.

Nancy

 

ASD P0688 is Auto Shutdown Sense. The dealer is taking you for a ride. If you have a bad coil, you'll have a misfire on that cylinder.

Maybe this will help:
http://ww2.justanswer.com/uploads/Sp...1_rt_p0688.pdf

 

thanks, but what does that mean? Sorry, I really know nothing about cars

Nancy

 

So does anyone think we should start with replacing the crankshaft position sensor and camshaft position sensor? What about the ASD relay? Is it bad?

I just don't want to go the coil route as one of the above posters mentioned that the dealer is taking me for a ride on that one. That seems to be the consensus I'm getting around here too.

I honestly know nothing about cars, but since nobody can figure this out I've had to do my own research and now want to tell the dealer what to do since they don't know what's wrong. This is so frustrating.

Thanks,
Nancy

 

No, it's related to the ASD. A decent mechanic should have picked up on this based on the stored code.

The ASD relay controls electronic funcitons and even the fuel injectors, so this would be a prime suspect given your truck just shuts down.

The relay could just be bad ($5 at any auto parts store) but it could also be a shorted wire connected to the system that keeps tripping the relay - this is common when the fuel pump has a bad wire and/or ground.

Step one: (and one that someone who has had this truck in for repair should have done in the blink of an eye) would be to replace the relay (or swap it out with one for another device such as the headlights). If swapped for say the headlights and the headlights fail to work - then you know you just have a balky $5 relay. If the relay is not bad then it's wire troubleshooting time...

 

Thanks - so you don't think I should do the crankshaft position sensor and camshaft position sensor too? Normally, I would do the relay first and see what happens. That truck has to make a trip from San Diego to Davis with a trailer in two weeks (my daughter is off to college). I'm running out of time. This has been going on for a month now.

Would it be ridiculously stupid and expensive to replace all three? If I had more time I wouldn't do it this way - honest.

Thanks for all the help. I really appreciate it.

Nancy

 

I've never seen a cam sensor fail without popping a code for it and I think I've only ever seen once or maybe twice where an issue was fixed by replacing the cam sensor when no code was present for it.

If it was me, I'd do the relay and if that didn't work I'd start looking for a bad wire starting at the fuel pump...

 

You're a gem!!!! Thanks so much for your help. I was told both the crankshaft position sensor and cam shaft position sensor may not throw a code when they are first starting to fail. Is that true? The stalling is very intermittent. It can go a few days and drive fine and then it stalls. Well I am definitely getting the PO688 code so I should tell the dealer to replace the ASD relay even though they want me to change coils one by one?

Thanks again,
Nancy

Edit to add - my husband just got home and told me the truck stalled two more times. Ugh Oh and it seems to stall when coasting/no foot on accelerator. Does that mean anything?