Transmission codes P0700 (P0750?)

dirtmover · **Posted:** Thu Oct 30, 2014 6:59 pm

Driving home from work it suddenly dropped from 4th overdrive to 3rd while cruising at just under 60mph.

CEL comes on.

Plugged my OBD adapter in and pulled P0700 using Torque.

Completed my journey home, about 3 miles. Wouldn't shift above 3rd and felt sluggish accelerating from rest.

Checked the codes again when I got home using an Innova 3100 scanner and also the GDE programmer. Both pulled P0700 but the Innova also pulled P0750, "Shift solenoid A", but not sure that this is the correct mapping for the CRD or even a valid code since the GDE and Torque didn't even read it.

Noticed the initial shift from park to drive or reverse is pretty rough.

I have also been experiencing a delayed shift into forward or reverse when it's been sitting for a few hours.

Any suggestions where to start looking? Obviously need to get the transmission codes pulled but is there anything I can look at before that. Reading about failed transmissions and TCMs is beginning to scare me.

gmctd · **Posted:** Thu Oct 30, 2014 7:05 pm

When was your last service, with oil and filter change?

dirtmover · **Posted:** Thu Oct 30, 2014 7:20 pm

Yeah, it's overdue by about 20K. I've got the filters sitting on the shelf ready to go so extracting the fluid and pulling the pan will probably be my starting point. I've read that the spin on can break off causing this problem. Anything else I should be looking for while I'm in there?

gmctd · **Posted:** Thu Oct 30, 2014 9:34 pm

Any burnt odor and color of the fluid, sparkles in the fluid indicating metal failure, then an excess of the usual brownish clutch material on the floor of the pan - you'll need to take care not to jostle the pan so the max evidence will remain in place

A 2005 model should be researched for F37 upgrade, with revised pump and TC

Most '06's were done in production, but wouldn't hurt to verify

dirtmover · **Posted:** Thu Oct 30, 2014 9:59 pm

To avoid mess I usually suck out the fluid before dropping the pan. I guess an autopsy on the filters will reveal any contaminants.

After a lot of reading I'm beginning to believe that the P0750 code is legitimate and points to the solenoid pack. The symptoms seem correct for this. There are also a lot of indications that the solenoid pack is one of the weak links in this transmission.

dirtmover · **Posted:** Fri Oct 31, 2014 8:52 am

The fluid looks and smells fine on the dipstick. I'll drop the pan this afternoon and see if there's anything more telling in there..

papaindigo · **Posted:** Fri Oct 31, 2014 9:50 am

P0700 is a generic "you have a stored transmission code" that is stored in the ECU which is why the GDE tool can read it. Generally speaking as far as I know only dealer or dealer equivalent code readers can pull TCM (transmission) codes; I know the GDE tool cannot and I have no clue if what the Innova 3100 pulled is valid although it is a listed KJ transmission code. FYI if you don't already have it go to http://colorado4wheel.com/manuals/Jeep/KJ/ and download a PDF copy of the 06 FSM and check out what it says about P0750.

Your delayed shift into forward or reverse after sitting a while is a classic symptom of transmission fluid drain back and/or low transmission fluid. If it's the former holding a high idle in neutral, not park as fluid pumps faster in neutral, for like 15 seconds before putting it in gear will correct the hesitation. NOTE: sometimes trying to drive right off after that hesitation will cause a "hard" engine stall and throw a transmission fault code which goes away after like 5 ok restarts. Can be related to a failed filter check valve or a problem with a worn part in the transmission pump; there is a newer and better pump but replacing the pump requires dropping the tranny.

Possible causes of the drop down in gears - clogged/split/detached filter; loose transmission valve body plate; low transmission fluid; solenoid problem

flash7210 · **Posted:** Fri Oct 31, 2014 10:24 am

Quote:

Possible causes of the drop down in gears - clogged/split/detached filter; loose transmission valve body plate; low transmission fluid; solenoid problem

Transmission input and output speed sensors are also a possibility.

dirtmover · **Posted:** Wed Nov 12, 2014 9:34 am

Since it was due a fluid and filter change anyway and I was hoping to resolve the drainback issue at the same time I went ahead and changed the solenoid pack since everything I read relating to the P0750 code pointed to this being by far the most likely culprit.

Unfortunately it made no difference :cry:

.

flash7210 wrote:

Transmission input and output speed sensors are also a possibility.

Any other symptoms of the speed sensors failing other than limp mode? Would I expect a generic code or are they transmission codes only?

gmctd · **Posted:** Wed Nov 12, 2014 6:30 pm

Assuming that none of your input indicates DTC(s) from the ABS module, which could indicate that your scantools cannot read the ABS, faulty output from that module can cause transmission symptoms, particularly the drop-down to a lower gear range - this has been seen on multiple occasions in the past when SCANGAGE and other scanners are connected for full-time monitoring of KJ CRD drivetrain operation - ABS module trashes them all and farkles TCM control, to boot

amslube · **Posted:** Wed Nov 12, 2014 6:49 pm

A couple of years ago I dropping the trans to replace the front pump and install a euro TC. I had the drainback issue and the stock TC so did both while the trans was out. After getting everything back together, the trans wouldn't shift out of 3rd gear. After driving a few miles, me in mostly a panic state trying to figure what may have gone wrong, it eventually threw a code. My Autel scanner (not an expensive tool) pulled a transmission code which pointed to the front speed sensor, I don't remember what the code was. Lo and behold I must have bumped the front speed sensor when installing a bracket and damaged the coil on the sensor. A trip to my local NAPA store got me a new sensor and tranny shifted great. So the not shifting out of 3rd can also be a speed sensor. I didn't experience any loss of power though.

dirtmover · **Posted:** Wed Nov 12, 2014 10:03 pm

amslube wrote:

A trip to my local NAPA store got me a new sensor and tranny shifted great. So the not shifting out of 3rd can also be a speed sensor.

I did take both sensors out and see a signal when a magnet is passed over them. They both behave the same so they are either both good or both broken in the same manner.

amslube wrote:

I didn't experience any loss of power though.

Yeah, I didn't fully understand limp mode until I did a bit more reading and realised you have minimal manual control thus:

P = P
R = Reverse
N = N
D = 3rd
2 = 2nd
1 = 2nd

Trying to get moving from rest in 3rd does a pretty good impression of loss of power. Now that I know better, getting it moving in 2 and then shifting to D is a lot more driveable.

dirtmover · **Posted:** Mon Nov 17, 2014 8:13 am

So, I buzzed out the harness between the transmission and TCM for continuity and shorts. Everything is fine.

This just leaves the TCM itself. Anyone know where I can get one for a decent price? Do they need to be programmed by the dealer or would it already be pre-programmed if I get the correct P/N?

Anyone got one to sell? PM me.

dirtmover · **Posted:** Tue Nov 18, 2014 8:21 am

So, I took it to a local shop and he was only able to pull P0750, same as my Innova

. According to him his SnapOn scanner covers the CRD and is able to pull any transmission codes. His unit is brand new as of two weeks ago. I also checked with the coverage matrix from SnapOn and what he claims appears to be correct.

He spoke to his buddy at a local transmission shop who claims that if you don't change the L/R switch valve at the same time as the solenoid pack the code will not clear and it will cause the new solenoid pack to fail. Not heard of that one before, in fact there appear to be other codes that should be set if that was the case. According to the FSM P0750 is purely an electrical fault so his story sounds like BS to me. He offered to fix it for $1,000 (and then another $800 for a new TCM when that doesn't work) :-)r

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Transmission codes P0700 (P0750?)

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