2003 48RE P700 Code

[Matt400]

I have not studied those two circuits on the 48re but on my 07 Charger the TCC signal is PWM so the engagement is smoother. Makes mystery switch harder to do. I am kinda surprised if on the 48re its either and on or off signal.

 

[JJPage]

I see, the word locked and "two" switches had me confused.

If I understand you correctly... you have one switch to lock the TC and one switch that forces and holds 4th gear, correct?

Yes, this is correct.



Depending on your VB build, locking the TC will lock the trans into OD. If the VB has been modified to allow the OD solenoid to exhaust when the TC is locked then you have to run the second switch.



When DTT setup my VB, at that time I was going to install an exhaust brake. Did not want OD locking with TC when the EB was applied.

 

[cerberusiam]

I have not studied those two circuits on the 48re but on my 07 Charger the TCC signal is PWM so the engagement is smoother. Makes mystery switch harder to do. I am kinda surprised if on the 48re its either and on or off signal.

That car has the 545RFE or something like that, correct? The new 68RFE I believe is like that with all the computer controls. The 48RE was really crude compared to enhanced units.

When DTT setup my VB, at that time I was going to install an exhaust brake. Did not want OD locking with TC when the EB was applied.

That makes sense, figured it was build thing.

 

[JJPage]

P0753

The circuit is monitored ofr 5-100 ohms resistance at all times I believe. Values outside that set codes and should set a CEL but withe PCM that did not always happen. the 10 ohm resistor is too close unless everything is perfect. I much prefer using a 30-50 ohm resistor to put the value about the middle of the monitored range.



As long as one maintains the resistance in the monitored range the ECU doesn't know and doesn't care if the solenoid is engaged, it can't tell if it is engaged or not. All the ECU cares about in the circuit is if the resistance is between 5 ohms and 100 ohms.





Cerb, you were right on the money here.



I started throwing P0743 along with the P0700/P0753, but only when I would hit both switches at once??? Then my truck started going into the limp mode.



Since these switches are in Parallel... I got out my trusty Fluke meter, these 10 ohm resistors in parallel become 5 ohms, too close to the low end range. I replaced them with 22 ohm 1/2 watt resistors and no more limp mode or codes.



Still waiting for the rest of my components to arrive, but at least I can drive my truck without the aggravating behavior.



Thanks, Jess

 

[JJPage]

Wanted to give you guys an update, I have all my new parts, governor pressure solenoid, transducer sensor, and a new APPS sensor from TMB Mechanical.



Since it is a windy day, and my truck will not fit in my garage, I decided to tackle the APPS sensor first. My GOD! What a difference, this is like a whole new truck. Shifts fantastic, I can feel the TC locking in 3rd and 4th just like when it was new, even better than I remember. Light throttle shuffle is completely gone, TC locks at 50mph in OD, I am so dang thrilled, this is almost unbelievable.



I understand I had multiple issues fighting each other, but I believe now, that this was the main culprit. I will still replace the trans components when I service it, but it is not so urgent now.



Any other 03/04 owners with an engine mounted APPS, if you are having any of the above issues, I strongly recommend an APPS sensor from Tim at TMB Mechanical, best $160. 00 I have spent in a long while. Tim is a very pleasant person to speak with, and my APPS arrived exactly the day he said it would.



I am still amazed at the difference this has made, I Love driving my truck again.



Thanks again, to all who have assisted me through this problem! Jess