Does anyone have experience with P1603 transmission code on 42RLE equipped 2005 TJ?

AudieMurphy

AudieMurphy

New Member
Joined
Oct 21, 2019
Messages
18
Location
High Springs, Fl
Hey fellow Jeepsters,
My TJ (Model in subject line) check engine dummy light came on a few months ago. I don't remember the two codes it displayed, but I think one was the p1603 and one was a transmission code. This started right after I got gas and left the gas cap on the pump. I put it back on and the codes didn't go away (maybe a coincidence?). Although the codes were for the PCM and TCM, it's been running great. No problems with the engine or the transmission function. Gas mileage hasn't changed either. This isn't my primary vehicle so it only has about 135K on it, and well maintained. My mechanic said sometimes there are low voltage problems, and since the battery was old, I replaced it and the serpentine belt. The light came back on right away. I also used a code reader a couple times to reset the codes, and the check engine light came right back on.
So, does anyone have experience with this? I've read several posts with the same engine codes, but they all were noticing problems, which I haven't. I live on dirt roads in central Florida, so it stays muddy/dirty.
Any help on this specific problem would be much appreciated...
 
  • Like
Reactions: Wranglerfix
Hate to be the bearer of bad news but it sounds like your pcm is slowly failing. I have the same year, engine, trans and it was pretty much the same process. Started up after getting gas, same weird codes (mine actually went into limp mode), they came back after clearing them, eventually got to the point where I couldn't drive without it going into limp mode.

2005 tjs and I believe 2006 sometimes have this exact problem with the pcm. To my understanding 05 was the first year that the tcm (transmission control module) was put inside of the pcm along with the ecm (engine control module). That's why you have 4 plugs on the pcm instead of 3. Somehow inside of there the ecm will lose contact with the tcm and think that the trans is having problems, throw those codes, and sometimes go into limp mode.

There was one thread about it I found on a different forum where the guy sprayed Deoxit to clean the little pins that the plugs plug into. He also opened the pcm and cleaned the back of the pins from the inside. Worked for him for a while then the problem came back. Didn't work for me at all.
https://www.wranglerforum.com/threads/huge-fix-for-2005-wrangler-x-with-42rle.1694569/

Other than that I've never seen an actual fix that lasted, other than taking it to an electronics shop or just buying a whole new pcm.

You might also get 4 separate 02 sensor heater circuit codes at some point.

If you do end needing a pcm, I recommend Wranglerfix. I got mine from them 5 months ago and have had zero problems. They don't sell them OR repair them at the dealerships anymore as far as I know.

Good luck on this, I've been there
 
  • Like
Reactions: Wranglerfix
Did you clear the codes with an OBDII tool? Did they come back after you cleared them?

If the PCM is failing I highly suggest talking to Mark (@Wranglerfix) as he is the go to guy for replacement PCMs at reasonable prices.

I'm going to tag him in this, since he will chime in.
 
  • Like
Reactions: Wranglerfix
AudieMurphy said:
Thanks for the info. You introduced a new term though, "Limp Mode" what exactly is that? Why hasn't Jeep recalled these modules if this problem is so prevalent?
Click to expand...

There is a plethora of problems with the 05-06 PCMS with no support whatsoever from Jeep.

The 1600 codes are failure on the ecm side of the pcm.

Limp mode is when the Jeep is stuck in 3rd gear and won’t shift out. This is caused by failure on the tcm side of the pcm and will usually throw a 0700 code, indicating something awry with the transmission.

The symptoms occur more frequently during the Summer months as pcms fail from the heat.

You have a faulty pcm. You can call me tomorrow to discuss in further detail.

Thanks,

Mark
 
  • Like
Reactions: Jerry Bransford
Chris said:
Did you clear the codes with an OBDII tool? Did they come back after you cleared them?

If the PCM is failing I highly suggest talking to Mark (@Wranglerfix) as he is the go to guy for replacement PCMs at reasonable prices.

I'm going to tag him in this, since he will chime in.
Click to expand...

Yes, I cleared them several times with the OBDII tool, and yes they came back almost immediately after clearing them. Thanks for the help, I'll call Mark on Monday..
 
  • Like
Reactions: Jerry Bransford and Wranglerfix
Thanks Mark,
I'll call Monday or Tuesday. Can you send your contact info, please? Is there anyway we can organize and file a class action lawsuit or something? These problems seem to overwhelmingly common in the 05-06 models. Now with the new Ford Bronco about to launch and take a piece of Jeep's market share, maybe they'll be more amenable to fixing this situation. Just a thought...
 
AudieMurphy said:
Thanks Mark,
I'll call Monday or Tuesday. Can you send your contact info, please? Is there anyway we can organize and file a class action lawsuit or something? These problems seem to overwhelmingly common in the 05-06 models. Now with the new Ford Bronco about to launch and take a piece of Jeep's market share, maybe they'll be more amenable to fixing this situation. Just a thought...
Click to expand...

You can find Mark’s contact info here:

https://wranglerfix.com/
 
  • Like
Reactions: Wranglerfix
Top Bottom
Back