michaelo

Hi everybody,

on my '99 4.0 the "Check Engine" light keeps on burning and my OBD II App (Torque) throws code P0743. Today I've changed all three solenoids in the trasnmission box, formerly I checked all cables, connections under the hood and the TCM according to a very good instruction in this forum. No faults showed up, the transmission shifts like it schould and the converter clutch works perfect!

The check engine light comes up after about 10 sec. after start, when I delete the code it comes again after 10 sec.! Sometimes, every 2 weeks probably, there ist no check engine light for about 50 kms, but then it comes again.

I'm a bit desperate now because to my mind I've tried erverything to get rid of this problem. Does anybody know how I can go on?

Greetings from Germany
Michael

dans98xj

if you have not tired it, try adjusting the brake switch that is next to the brake pedal. It works that break lights but also effects the lock up of the torque converter.
read the first post here
http://www.xjtalk.com/showthread.php?t=7710

try this and see if it helps.

michaelo

Thank you very much, that sounds really interesting. I'll check this tomorrow.

CCKen

It might be a transmission Input Speed Sensor (ISS) fault or a TPS input signal fault.


Try checking the resistance of the transmission ISS (and OSS) and the TPS voltage inputs to the TCM


Use a digital Volt/Ohmmeter.


Refer to the TCM pinouts and test procedures below.


The ISS/OSS and TPS specs are in the test procedures.

michaelo

Hi, this is exactly what I meant in my first post "good instruction", I did the whole procedure some time ago and everything was ok.

michaelo

Today I checked the connector (black) near the dipstick for resistance. Pin 1-3 show 12.9 ohms, Pin 4 (black and red cable) doesn't show anything.

Pin 1

Pin 4

Does that mean that there's something wrong with this cable? Is it right that this cable supplies solenoid C (lock up)? I would now try to replace this cable from the connector down to the transmission as far as possible. My problem ist that the solenoid harness adaptor seal at the transmission is hidden behind the 4WD shift gear and I can't reach it without disassembling this.

CCKen

Assuming you are reading the Transmission Control Assembly (TCA)connector (see pic) and using the TCA pin out, you should have 11-15 Ohms on pin cavities 2, 3, and 4.


You should have been able to read these solenoid resistances from the TCM connector.



.

.

michaelo

Yes, I read from the TCA Pin out, but there is nothing on no. 4, like my 2nd pic shows. What confuses me is the fact that the black/red cable going out from no.4 ends in the trans input speed sensor. The TCA cable has a Y-Split, one part goes to the speed sensor, the other one to the solenoid harness adaptor seal at the back of the transmission. But there goes only a black cable, no black/red...

CCKen

The wire colors in the TCA pin out are the wire colors from the body harness. The wire colors from the transmission side of the TCA connector may be different than the body side - not unusual for these transmission connectors. If you go by the wire colors in the body side connector make sure the pin/cavities match up in both connector halves.


Also, the pin cavity numbers shown for the TCA connector are the numbers for the body side of the connector. Reverse these numbers when looking at the transmission side of the connector. You may be confusing 1 for 4.


With this in mind, recheck the resistances.


If you see zero continuity in pin 1 cavity (ISS), read from 1 to 5. You should see 620 (+/-) Ohms.


Edit: This is why I encourage people to do voltage and resistance readings from the TCM connector. Taking readings from the connectors at the dipstick can be confusing. If there is a bad reading from the TCM connector, then go to the connectors at the dipstick. There have been cases where the wiring from these connectors to the transmission/TRS get chafed and opened or shorted to each other or to ground. Always wiggle wire looms in the transmission area to see if readings at the TCM change.