The solenoids are all permanently connected to +12 Volts via pin 38 on the TCU which becomes pin 6 on the round connector on the transmission. When it is time to activate a solenoid, the TCU connects its opposite side to ground. See wiring diagram.
I don't know about the voltage for the hall effects.

One more thing. If the transmission is in "limp mode" you shoukd not see the 12 volts solenoid supply voltage present at all on pin 38

Hi Ace,

Ok, Pin 38 on TCU is giving 4VDC, not 12VDC and pin 13 on the TCU which is the supply voltage for the hall effect is giving 6vdc.

How would I know if the car is in limp mode, I do have the two error codes p0715 and P0763 showing, and I can clear them via the OBDII scanner, but some how I was reading your other post and you mentioned that I can't clear the limp mode via the regular Obdii scanner.

How can I tell if the TCU is in limp mode.

Lets say the hall effect is causing my problem and I went ahead and replaced it, would the car kick itself out of the limp mode or do I still need a special tool to clear the limp mode.

Thank you,

Rafi

For the TCM to work it looks at and needs input signals from the transmission RPM sensors N1 and N 2 as will as wheel and engine RPMs signals. Did you scan ALL modules for codes. If not, you should start there.

The cause of Code P0715, Turbine speed sensor can be electrical or mechanical; the exciter ring for the Turbine speed sensor is located on the front carrier assembly, front window near the bell housing, since you removed the valve body check the ring for any looseness, use a small screw driver and gently try to move it, Compare any movement to the N2 exciter ring, if the ring moves without the attached drum moving you have to replace it, internal.

The N1 and N2 exciter ring sheet metal window for both exciter rings should be centered in the middle of its hole in the case, if not the transmission must be removed. If you have no exciter ring looseness/ movement and are centered in its window.


The N1and N2 sensors are 3 wire Hall Effect sensors, they generate a square wave. It’s best to do electrical tests in real time, with all test components working. Do a pin point test at the TCM; remove the TCMc protective cover to access the wire terminals, with the engine running and the rear wheels safely off the ground carefully back probe terminals #33 N2/N3 ground and in gear, a good ground is .01volts anything higher is to much resistance, check and clean all body ground points.

Terminal # 13 sensor voltage supply you should see 4 to 8 volts

Terminal #12 and 35 are N1and N2 out put signal; you should see a square wave with precise time duration, between rising edges to mark off time.

P063 is a 3 / 4 shift solenoid, terminal # 15(4 to 5 ohms)

If you have no exciter ring looseness/ movement, and is centered in its window, and if the square wave output signal generated by the NI/N2 is bad. Change the conductor plate and 3rd to 4th shift solenoid.

Limp mode is when the TCM turns off all power to the solenoids and sets a diagnostic trouble code. The below link will explain why.

http://www.peachparts.com/shopforum/tech-help/138071-e420-transmission-control-problems-post1024068.html#post1024068

Hi C32AMG,

Every thing you mentioned, I have already done but with the car is turned off while the ignition key is fully turned on due to that the bottom of the tranny is apart.

With the ignition is open, the hall effects are generating a square wave and they ave 6volts as input supply.
I tested teh hall effect sensors while the ignition is turned on and I used a metal screw driver and tapped it against teh N1 and N2 magnits and I can see a very nice square wave.

all the selonids measure good roughly 5-6 ohms
TCM is getting 12vdc input on pin 29 but on pin 38 I am only getting 4.0v and from the link you directed me to, it mentioned that I should be seeing 12vdc, unless the car is in limp mode then I shouldn't see any voltage.

So, I am starting to suspect the TCM is bad, I took the TCM apart and I don't smell or see any burnt electronic components as well as it is very dry, no signs of moisture, or liquid spill.

I guess when I replace the N1 and N2 circuit, I need to use a special MB tool to take the car out of limp mode, which I don't have this dam too.

Thanks every one for your great experience and input, I will let you know what goes on, when I replace the N1, N2 hall effects on Tuesday, as I order these parts yesterday and I should have them by tuesday.

O ya, there is no play in the N1 N2 windows on the tranny side, The car has only 20K miles.

Does any one have a spare TCM willing to sell it that is in a good working condition?


Thanks again,

Rafi

The TCM is variant coded to the VIN, you can not use any other TCM it will not work and it must be the same model car. Try them http://www.beckmanntechnologies.com/policies.html

Hum,

When I bought the car from the auction, the car did not come with the ignition key, it was missing, so I ordered it from the chrysler dealer, do you think they might not have programmed it correctly that might cause my problem?

The car starts with this key. How would the car recognize the TCM ecu?, I can see that with the engine ECU.

Cheers,

Rafi

You could never start that car with the wrong coded key, it’s also VIN coded. The TCM and ECU are coded with VIN specific information, engine size, transmission type, Rear end ratio and more specifies information. When installed in the vehicle its software flashed. The TCM and ECUs are not vehicle interchangeable, only if you find the exact same vehicle.



As of 2003 TCMs and engine ECUs have a software calibration number which identifies control unit software and coding conforming to the vehicle. The SCN also prevents after market software performance enhancements.

ok,

I don't believe this will make a difference, but I thought I would mention it.

When I bought the car, the a/c bracket was broken due to the accident, as well as the power steering pump, so the other crossfire which I bought for parts (severe rear end damage + it was a 5spd), I removed the engine from it and install it in my current car.

Do you think changing engines will cause this issue? I used the harness from the other engine, as I removed the engine and the harness as one piece, I didn't disconnect the harness of the engine, the only place I disconnected it from, was from the ecu side.

So, know I have a 5spd tranny and tons of parts that are no good to me as the automatic car was much easier to fix, what a dam headache.

Cheers,

Rafi

after some serious troubleshooting, I finally determined that the TCM is defective, but I can't just order one, as it needs to be programmed by the dealer, so I took the car to another Chrysler dealer and they replaced the TCM, I haven't picked up the car yet, but they said that it is ready and the TCM was defective.

Thanks every one for your great help.

Cheers,

Rafi

If the VIN numbers in the TCM, and engine ECU do not match, you will have similar problems.