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imnotted 11-25-2013 02:01 PM

WK CRD - pending P0638, flashing ETC, no limp mode
Hey guys. So, +5 months after a nasty front end collision that totaled out my WK CRD, I have it rebuilt and back on the road. Today, however, I started getting a flashing ETC and a pending but not logged P0638 - Throttle Actuator Control Range/Performance fault. It seemed like it was in limp mode at first, but came out of it. I'm still not used to the massive turbo lag now that I'm 6 months removed from driving my Jeep. I know on my way back to the office it was definitely not in limp mode despite a blinking ETC.

My first thought even before scanning was the battery. I have a weak battery, and I planned on replacing it tonight regardless. I don't think it would cause such a specific code, though, so I am looking at other causes.

Upon seeing the pending code, my second thought was swirl motor, but I'm running a GDE tune, so that should nullify swirl motor issues. I just had it at the dealer to track down an airbag fault, but I assume there's no way they would've cleared out my tune.

I could have a loose or pinched wire somewhere, but the collision barely went to the motor. It hit across the front but deeper on the driver's side and damaged all 4 coolers, pushed the rail over, knocked the cover off of one of the PCM harnesses, etc., but the only thing on the motor it broke was the oil pressure sensor connector. I'm inclined to believe this is related to either the temperature or poor voltage supply, but that doesn't sit right with me. I would think this would be an issue with the TPS or actuator, like the code suggests.

Am I correct in thinking the throttle body sits just behind and downstream of the intercooler on the passenger side? Anybody have any ideas on this one? I'm at a bit of a loss, and I'm incredibly tired of paying for parts. I'm really hoping it's just a loose or pinched wire. Thanks for any advice you can provide!

imnotted 11-26-2013 08:26 AM

Quick update, I replaced the battery last night and it didn't hesitate on start this morning. No blinking ETC or pending P0638, but that was the case on my drive home, too. I inspected the TB and didn't see any noticeable damage. The harness looks pristine and it routes pretty high along the top of the engine, which is an area that was mostly avoided. I think I'll just chock it up to quirky electrical problems stemming from a weak battery until I see it again.

Blue_Sassley 11-26-2013 08:37 AM

Were you able to have a CCA test on your old battery? It would be interesting to see how weak it was.


imnotted 11-26-2013 09:21 AM

Walmart tested it for me. It was at 775 after a full 90 minute test. It's rated at 900, so it wasn't terribly bad. I briefly considered a short or an abnormally high load when off, but the Jeep is only pulling about 120mA a minute or two after it is turned off. It's a little on the high side, but not high enough to explain a battery dying (and by dying, I mean dropping to 24 CCA) in under 2 days if not driven.

It's weird. If I drove it, the alternator had no problem charging the battery up. No dimming, no hard starts immediately after, etc. But if I let it sit and get cold, the battery drops to nothing in a relatively short time. I suspect the battery got damaged, either in the collision or when it was sitting outside in the rain at the body shop. It was pretty tightly sealed when I pulled the caps off, but that doesn't mean water didn't get in there somehow. We'll see how the next few days go.

Blue_Sassley 11-26-2013 10:27 AM

Yeah that is weird, maybe had a bad cell?


Radcrd 11-26-2013 01:13 PM

A failing battery will cause all kinds of electrical gremlins on these trucks. My auto stick stopped working and shortly thereafter no-start one day.... If the battery is over 5 years old change it.

imnotted 11-26-2013 04:59 PM

6 starts later, still golden. Not even a slight hesitation on this battery. It was only a year old, but I'm guessing it had significantly reduced capacity from running all the way down and sitting outside for a month - basically enough to pass CCA tests but not enough Ah to sustain typical starting loads. I read a great thread/debate over on the TDIclub forums about the importance of Ah (capacity) in diesel batteries because of the glow plug factor. It made a lot of sense, and I think it's worth weighing in future battery choices. A lot of systems run with the key on before start, and it is important to have both CCA and significant capacity to sustain the typical draws on cold starts.

Blue_Sassley 11-26-2013 05:04 PM

Yeah makes a lot of since, can you post the TDI link?

Chirpz 11-26-2013 05:10 PM

How OLD is your GDE tune. The swirl motor delete was not a part of the original tune. It was added after I purchased my tune and I had to get an update.

So...if your tune is older than a year or so you might inquire. Swirl could still be an issue in that case.

OK, I my tune 5/9/2012

imnotted 11-26-2013 06:31 PM

Chirpz, I got my tune in January of this year so I should have it.

Blue, below is the link to the discussion. It's a little long, but worth the read. I was just looking for the Ah rating on my battery (MAXX-H8) on my lunch and I got sucked in! If you want to skip to the meat of the discussion, look for where puter and NB_TDi get into it. What puter has to say about capacitance is spot on imo. At the very least, it's a great explanation of the difference between CCA and Ah and their relevance in an automotive electrical system.

Phil_Dunphy 12-15-2013 09:20 PM

Still good with no blinking light? Just asking because I have same exact issue. Comes on about every 5th or 6th start, blinking light with CEL. No limp mode but once after it was on for a while. Usually by the next start or start after that the blinking light goes away but cel stays. Then eventually both are gone...then that process repeats.

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