SG Mason

I have been chasing a P0705 for some time now. It all started with a flex plate replacement that turned into a transmission swap because I broke the the threaded part off the manual shift valve shaft. The replacement transmission is from another 1998 XJ Sport so it should have been a simple bolt in, plug in and go deal. That led to a P1694 fault and with the help of CCKen I traced it to the TCM. It turned out that the TCM that was in the Jeep had a 97 sticker on it. I replaced the TCM and started getting a P0705 fault along with a P0700 and CEL. I took off the NSS checked the connections, took it apart, cleaned it, installed and adjusted it. That cleared up the P0700 fault and CEL, but it still throws the P0705.

Everything works as it should, and I get proper readings on the DVM at both the TCM and NSS connectors. Problem is that the P0705 will most likely cause the Jeep to fail the Ontario emissions test, which I need to keep it road legal. Yeah I know, it is complete bull crap that a transmission code will cause a vehicle to fail an emissions test, but that is beside the point.

So here is the run down on my XJ and what I have tried to solve the problem

1998 XJ Sport 4.0L AW4 with a Prostart CT-3300 remote starter
replace the transmission with another 98
replaced TCM with a 98
cleaned and adjusted NSS
tried a NSS that is know to be good
adjusted the kick down cable
unplugged the command start (completely uninstalling it is not possible till spring due to having to work in the driveway and it is winter up here)

I can clear the code, but as soon as I start the Jeep the code comes back as soon as I start it. I am going outside to try adjust the gershift cable right now and after that I am out of ideas.

CCKen

So, you are getting good voltage readings when you check pin cavs 9, 21, and 22 while you shift through the gears?

Is the trans going into Overdrive?

Here's a list of possible causes for 705:

PCM PARK/NEUTRAL DTC’S PRESENT
INTERMITTENT WIRING AND/OR CONNECTORS
FUSED IGNITION SWITCH OUTPUT OPEN OR HIGH RESISTANCE
TRS 1-2 SENSE CIRCUIT OPEN
TRS 3 SENSE CIRCUIT OPEN
TRS OVERDRIVE SENSE CIRCUIT OPEN
TRS REVERSE SENSE CIRCUIT OPEN
TRS 1-2 SENSE CIRCUIT SHORTED TO GROUND
TRS 3 SENSE CIRCUIT SHORTED TO GROUND
TRS OVERDRIVE SENSE CIRCUIT SHORTED TO GROUND
TRS REVERSE SENSE CIRCUIT SHORTED TO GROUND
TRS 1-2 SENSE CIRCUIT SHORTED TO VOLTAGE
TRS 3 SENSE CIRCUIT SHORTED TO VOLTAGE
TRS OVERDRIVE SENSE CIRCUIT SHORTED TO VOLTAGE
TRS REVERSE SENSE CIRCUIT SHORTED TO VOLTAGE
TRANS RANGE SENSOR-SENSE CIRCUIT
TCM-TRS SENSE CIRCUIT INPUTS

SG Mason

I did the same diagnostics that you had me do for the P1694 and everything is within a few of points (higher due to a fully charged battery) of the original readings. The only thing I can think of is that stupid remote start and there is no way I can fully uninstall it right now. I did try unplugging it and the power door lock module though. It made no difference.

I just finished adjusting the shift cable, gear indicators line up perfectly now. It still only starts in park and neutral, brake and reverse lights still work, and all the grounds were cleaned and fixed when we were chasing the P1694. It runs like a charm and shifts great with no hesitation. If I didn't have a code reader I wouldn't even know there was suppose to be something wrong. I can clear the code or so I think I can because it doesn't show if I let the reader cycle through. My code reader is a cheap one (Innova 3030F) so that could be the real problem and it isn't really clearing the code.

SG Mason

OK is it odd that the P0705 just went away I haven't tried clearing the codes in a couple days now because I needed the computer to go through all its emissions checks for the e-test on Friday. The last time i had the code reader plugged in, Monday, the P0705 was still there. I have been just driving it over the last 2 days and haven't done anything other than change the bulbs for the 4WD indicators. Plugged in the reader 10 minutes ago and no codes, not even the one that was there on the last reading.

Oh well all OBD2 emissions checks are done now and they all pass the home test, we will see what happens Friday afternoon.

CCKen

You probably fixed 705 when you rebuilt your NSS. Some codes will go away after a preset number of drive cycles and the PCM doesn't see the fault any longer.

SG Mason

Well fingers crossed that is it Guess that my cheap little reader doesn't clear the TCM and that is why I still had the code after the clean and rebuild. It would clear the PCM, but not the TCM and as soon as I started it the same code would be sent back to the PCM.

Sometimes electronics can be so frustrating

CCKen

Trying to troubleshoot using cheap testing equipment can add to the frustration.

Let us know how it went Friday afternoon.

Cheers

SG Mason

I much prefer the data logger I use for my Stealth, I can see in real time what each sensor is doing. Unfortunately it is OBD1 and made for Mitsubishi baud rates, I know there is some Mitsubishi in the Jeep , but it is OBD2

SG Mason

I have come up with another theory as to why the fault code just vanished. While reading the owners manual for the command start, took a lot of searching to find it online, I found out I could disable start function, yet retain the power door locks without disconnecting anything. The same day I replaced a couple of dash lights I disabled the start function. That just happens to be the same day the fault code went away:confuse:

Either way it is still gone and things are working fine. I have put over 150 miles on it since then and it 24 hours I will know if it passes the emissions test.

40xj

I just went through the same issue with help from CCKen as well. I cleaned all the grounds and nothing cell was still on. I took it out and drove about 5 miles to a friends house parked it for about 15 minutes. Started it up to leave and the light went out. The choose was still there but the light was out. I don't know what cues the system is using but I know some newer vehicles will store codes for a long as 40 NOT runs. Mine passed emissions in NY about 200 miles ago and still no light.

SG Mason

Well still no DTCs or CEL, and it passed the emissions test this afternoon. I think i am going to enable the command start again just to see if the p0705 comes back when I do. It is a sure way to tell if that is the cause or if it just kept showing up because my code reader wouldn't erase the TCM.

CCKen

Glad it passed.

It would be interesting to see if that command start gizmo causes the problem, but I can't see how it would. Unless it tinkers with the NSS to make sure the trans is in Park before starting the Heep (?).

SG Mason

I never got around to checking out this evening, by the time I finish making and eating supper I didn't feel like doing anything other than sitting on the couch I never use the command start, just the power door locks so having it disabled makes no difference to me.
Tomorrow morning I will be re-bleeding the brakes and dropping the TC 1" to see if that solves my vibration and noise I have been getting. I am going to replace the u-joints after Christmas no matter what, but it never vibrated before the lift and if it is the angles, putting in new u-joints before that is fixed is kind of a waste. Besides making and installing spacers is free I will enable the starter while I am doing that work and report back.

SG Mason

Enabled the command start this afternoon and it didn't set off the p0705, at least not yet. I will leave it enabled for another day or two and see if anything happens, but it is looking more likely to be my reader doesn't clear the TCM.