Limp Mode after LQ9 4l60 Swap
03-01-2014, 05:16 PM
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Limp Mode after LQ9 4l60 Swap Help me please. I swapped in a LQ9 and a rebuilt 4l60e into my chevelle and now all I have is 2nd and 3rd. The trans is a level 2 rebuild and the TC is a 3500 stall. The trans has the short shifter shaft and I was not able to use my truck range selector switch. I have plans to get a PN input to the ecm but havent yet. I have read that the range selector is not required for the trans to function properly. I was getting a code for the range selector but disabled it by setting it to none on the range selector option using HP tuners. I am getting no codes and I do have 12 volts on pine E. I am sure its a wiring issue because I had initially planned on running my th350 and had to go back and re-install the the trans wiring in my harness. Any advice would be appreciated.
03-01-2014, 06:42 PM
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My limp mode had no converter lockup. Mine was a shift solenoid code being set off, but if yours is throwing no codes then I'm not sure what the next step is.
03-01-2014, 07:33 PM
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I wish it had a code but Its gotta be something I did wrong when I added the trans plug back to the harness. Ive got a plan on how to check the wiring, I just got to get it done. Its not intermittent so it should be easy to figure out.
03-01-2014, 09:55 PM
#5
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The "pressure switch manifold" mounted on the valve body has an electrical connector and this tells the PCM which position your shifter is in.
I wonder if the code for the "range selector" indicates a problem with the pressure switch manifold or the wiring going to it.
I've linked to this many times, but here is the wiring diagram for the 4L60E:
http://www.msgpio.com/manuals/mshift/wiring.html
In other words, I don't think the missing external "range selector" has anything to do with your problem.
I wonder if the code for the "range selector" indicates a problem with the pressure switch manifold or the wiring going to it.
I've linked to this many times, but here is the wiring diagram for the 4L60E:
http://www.msgpio.com/manuals/mshift/wiring.html
In other words, I don't think the missing external "range selector" has anything to do with your problem.
03-02-2014, 08:04 AM
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I found a list of common 4l60e problems and this describes my issue exactly.
11. No 1st or 4th available; trans shifts 2nd to 3rd by itself in D or OD and locks the converter : ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.
I verified wiring and it is correct from PCM to trans and the solenoid is reading 5 ohms. I have read that 20 to 40 is normal and solenoid B is reading 21. Looks like I will be pulling the pan...ugh.
Here is the common problem list. http://www.gmtruckhq.com/?q=node/93
11. No 1st or 4th available; trans shifts 2nd to 3rd by itself in D or OD and locks the converter : ShiftA solenoid failed. Easy fix in the pan. Or a wiring problem from PCM to trans.. or PCM.
I verified wiring and it is correct from PCM to trans and the solenoid is reading 5 ohms. I have read that 20 to 40 is normal and solenoid B is reading 21. Looks like I will be pulling the pan...ugh.
Here is the common problem list. http://www.gmtruckhq.com/?q=node/93
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03-04-2014, 01:03 PM
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Keep us posted on what the problem turns out to be.
I probably should have suggested Shift Solenoid A, but when there is a trans problem immediately after a swap into an older car, the problem is electrical. Also, I assumed the trans was very recently rebuilt and/or tested.
If you haven't pulled the pan yet, let me suggest pumping out most of the ATF through the dipstick tube using a $10 hand pump from Harbor Freight or your local parts store. This greatly reduces the mess.
Next you might consider installing the truck pan as it holds an additional quart of oil and has a drain plug. That extra quart has helped many members here reduce flares and slippage during WOT shifts.
Last remember that a shift solenoid can get mechanically stuck, or its filter clogged which will not throw a code and will read OK with an ohm meter. Shift solenoids are only $12 each; just replace both, which ensures you don't accidentally replace the wrong one.
I probably should have suggested Shift Solenoid A, but when there is a trans problem immediately after a swap into an older car, the problem is electrical. Also, I assumed the trans was very recently rebuilt and/or tested.
If you haven't pulled the pan yet, let me suggest pumping out most of the ATF through the dipstick tube using a $10 hand pump from Harbor Freight or your local parts store. This greatly reduces the mess.
Next you might consider installing the truck pan as it holds an additional quart of oil and has a drain plug. That extra quart has helped many members here reduce flares and slippage during WOT shifts.
Last remember that a shift solenoid can get mechanically stuck, or its filter clogged which will not throw a code and will read OK with an ohm meter. Shift solenoids are only $12 each; just replace both, which ensures you don't accidentally replace the wrong one.
03-05-2014, 05:28 AM
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It was the solenoid. I changed it after work yesterday and now it works great. The trans was rebuilt and was supposed to have had new solenoids put in it but no way for me to know if the guy actually did what he said.
