markeheiden

I have been fighting a shift problem since I got my truck running. 2007 5.3 w/ 4L65E. I have an External speedo driven VSS that is wired per the schematic directly to pin 16 and 41 on the TCM.

The ECM schematic shows the same two wires (circuit 821 and 822) on pins 71 and 72 connecting to "transmission system".

I understand how the signal gets from the VSS to the TCM but there is no TCM out to ECM???

Can anyone tell me from the attachment how the signal gets to the ECM?

Doubledip

Speed signal from TCM Pin 5 (Replicated TOSS) ORG/BLK to ECU X1 PIN 71 (TOSS HI)

markeheiden

OK, I'll trace that wire out, but what about VSS Lo Sig pin 72 on ECU? Where does it come from? It shows a Lt Grn/Blk wire on circuit 822 same as from the VSS to the TCM?

Doubledip

VSS Lo Pin 72 is only used in the Manual application...

so manual has the speed sender going to to VSS Hi Pin 71 and VSS Lo Pin 72

in auto the VSS Hi and Lo of the sender goes straight to the TCM 16 Lo 41 Hi
then out on 5 to the E38 X1 Pin 71.. and pin 72 not used



have you got the correct OS in both the E38 and T42 ECU/TCM

also does your 4L65E have an ISS? (input speed sensor)... not sure in the States but in Australia there were also a lot of 4L65E autos not fitted with the ISS and the E38 by default looks for this otherwise wont work correctly

markeheiden

Hi Doubledip, My transmission is a 4wd from a 2006 Yukon so not sure if there is an ISS? I never noticed it before but there is an ISS shown on the 2008 automatic trans schematic that I have been working from. What does it use the ISS for if it has a VSS?

The VSS was originally located inside the transfer case on the Yukon. I have an older transfer case and had to use an external pulse generator that plugs into the speedo cable output. I recently discoverd that there is a gear reduction (for speedo output) on the this cable so the 8-pulse generator I have was only providing 3 pulses per rev. I had the programmer drop the VSS pulse per rev. from 8 to 3 and saw no change in the shift points.

This is what started me looking for missing wires or connections from the VSS to the ECU.

Thanks for clearing up the Replicated TOS signal question.

Doubledip

the ISS i think is used for better torque management control..

you will definately need to check if your box has the ISS .. as stated in standard E38 OS form it is needed (from what i have seen) .. also has the tuner changed the correct setting in the E38 for this 8 - 3 pulses per rev.. not changed the output pulses.

have you checked for codes????

markeheiden

Yes, He changed the program to expect 3 pulses per rev. from the 8 we started with. No codes are being set.

To check if I have an ISS I should be able to ohm from pin 3 to pin 45 of the TCM and see a resistance like a magnet coil right? I suspect if I turn the drive shaft that resistance would change as the ISS turns correct?

Any other suggestions assuming this is all wired right? My engine came with a complete engine, ECU, TCM and transmission loom intact. I plugged it all in and broke in where I needed to add the Throttle pedal, power, etc. but otherwise everything has just worked. Also running no BCM so ignition, start, fuel pump etc. is handled with manual switches. Programmer removed all the VATS etc. that would have set codes.

The shift symptom is that it holds 1st gear way too long under part throttle and won't shift until you let off the gas. Then it shifts hard to second and the same thing, it holds second way too long and will only shift if you let of the gas. Then it shift good into 3rd but if you add throttle in 3rd, it shifts back to 2nd and is screaming the rpms again. I can't find a place big enough to find out if 4th gear even works cause Its going so fast by the time it hits 3rd.

Thanks again for staying with me on this!

markeheiden

I checked for continuity from pin 3 to pin 45 on the TCM and have an open. That would indicate that either there is a missing or broken wire or the transmission does not have this ISS signal generator in it?? Is that possible on a stock 2006 Yukon 4wd 4L65E?

No wiring problem, I have continuity from each pin 3 and 45 to the transmission connector but nothing across the two pins.

Should the ISS have continuity across it? If it is in fact missing, what would be the easiest fix? Can the ECU be re-programmed to ignore the ISS and work with only the VSS? Can an ISS be added easily?

This sucks!

Doubledip

is the engine and transmission , ECU znd TCM all out of a working car.. or are they from different cars etc....

Doubledip

so with this you removed the plug from the tcm and measured down the wires towards the gearbox?

markeheiden

Yes, First I measured across the connector pins on the TCM and ECU harnesses. These wires should go thru the trans connector to the ISS and back and I think it should read some resistance if the ISS is there. It didn't.

Then I measured from the connector pins on the TCM and ECU harnesses and verified that they make it to the transmission connector and they do.

I can't measure the connector on the transmission while it's in the car. (no room) but I suspect it must measure an open.

PS Engine, ECU and TCM from 2007 truck, trans from 2006.

Doubledip

Yes the tune can be changed to ignore the iss


What software is the tuner and who is he ?

markeheiden

He uses HP tuners and is located up in Washington state. He has done quite a few tunes for other 4wd guys and they work out well. If my trans doesn't have this Input speed sensor at all and the ECU is looking for it shouldn't it set a code? Is there a field in HP tuners to select transmission and year of transmission?

I have verified that I have a harness connection from my TCM Pin 3 (Iss sign) to the trans connector pin K and from pin 45 to trans connector pin V. Does this mean my trans should have an input speed sensor?


CAVITY FUNCTION WIRE COLOR
A SHIFT SOLENOID A (LOW) PINK/BLK
B SHIFT SOLENOID B (LOW) PINK/RED
C PRESSURE CONTROL SOLENOID(power)VIO/BLK
D PRESSURE CONTROL SOLENOID(ground)BLK
E BOTH SHIFT SOLENOIDS, TCC SOLENOID AND 3-2 CONTROLSOLENOID(power)RED
K SPEED IN ORG/LT GREEN
L TRANSMISSION FLUID TEMPERATURE (power) YEL/ORG
M TRANSMISSION FLUID TEMPERATURE (ground) BLK/WHT
N RANGE SIGNAL “A” GRY/BLK
P RANGE SIGNAL “C” GRY/LT. GRN
R RANGE SIGNAL “B” GRY/RED
S 3-2 CONTROL SOLENOID (ground) VIO/RED
T TCC SOLENOID (LOW) PINK/LT.GRN
U TCC PWM SOLENOID (ground) VIO/LT.GRN
V SENSOR GROUND BLK/WHT


I have seen other 4L65 end views that don't describe pins K or V at all.

What's up with that?

Doubledip

4L65E with or without ISS.. this is what i stated before.. .some do and some don't .... the 4L65E is a stronger box with more plantary gears etc..... so just because its a 4L65E doesnt mean it has the ISS... the part that requires the ISS is the E38 ... but if the running gear (engine/trans ECU/TCM and wiring harness) are all a matched set along with the OS in the ECU then i cant see why it is not working... and if the Looms are of similar design to the ones in Australia then i cant see why with out the correct powers/earths it is not working..

Now i know in HP Tuners it doesnt allow you to turn off the ISS in and out codes, but i guess it should still see the codes if they were set.. is the tune standard? (ie trans section and shifting points etc.... ) if not it may be best to go back to a stock starting point (stock tune for the vehicle O/S that the engine was from) and go from there...


just went through a few emails... I personally have never driven a car that is suffering this problem, but a customer of mine had the issue and he described it as

" Just a query the car started straight away no issues with the wiring all systems worked straight of the bat, but after the exhaust was finished went for a test drive and the car would not shift out of first gear, "

and

"Sorry to keep contacting you but we are still having problems. The gear box shifts fine but the car seems to drop or trip into a safe mode or loose throttle we can not tell as no trouble codes are up. It pulls away strongly and you can feel it drop or trip out some times it is fine and takes off like a rocket but most times it drops out straight away till it is in top and then cruises along quite nicely. Same story with kickdown sometimes kicks down and accelerates fine but most it goes into the mode described. We have checked the auto over carefully and checked everything possible and it has only behaved this way since the computers have been reflashed can you help, have any suggestions?"

he then also spoke to me over the phone and did describe that the upshifting would only happen when you backed off the accelerator.

another thing to check is the brake pedal wire.. have you wired this in. it is another common thing overlooked...

just dont want to be heading down one path here with you fully focused on the ISS when it may be another problem

one way to know it there is an ISS is to scan the car while driving and view the input speed - cant remember if it is a PID that can be selected on HP tuners but can be view ia tech 2

markeheiden

In fact I don't have the brake switch wired in but I expect that would only affect the TCC which is not engaging at all of course. Without a body control module, what else would this switch affect?

I don't have a scanner to diagnose with just a code reader. Have been trying to avoid taking it to a shop and paying cubic$$ to sort out a problem on a conversion with less than professional level documentation. (I can read my own chicken scratch, but don't think someone else could)
It may come to that at some point but I don't wan to give up just yet. I have made the whole thing work to this point and am one small discovery away from having it done.

Doubledip

the brake switch i think as well as TCC lock up uses it to know when the brake is applied for torque management ..... so it will affect performance as the ecu thinks you are driving around with your foot on the brake.... we had this experience with a GEN IV conversion into a jag... stepping on the accelerator would result in a slow take off... wired in the correct pin for brake switch and the Jag broke into wheel spin when stepping on the pedal from a stand still...

this is why us shops charge $$$$$$ because we have the information and have invested many hours of research and lost pay on working on customers cars to ge this information ....it is a common problem/misconception that the average joe thinks that some shops charge way to much for diagnosis etc... when they feel that what the shop is offering they can do themselves....

markeheiden

Hi Doubledip, Please don't take my comment on going to shop the wrong way. I know how valuable the time is and after this project how smart you have to be to figure all this out. My problem is that this is such a custom deal that anyone no matter how skilled would take a great deal of time to figure out what has been done on this conversion in order to know where to look.

That's why it's up to me to figure it out since I selected the engine, stuck it in an old jeep wtih a different trans and transfer case, re-wired the whole jeep starting with a fuse box from a 2007 and only documented what I needed to keep it all straight in my head. Beleive me, I would gladly give this project to someone else to sort out but it would be there a month if I was lucky.

markeheiden

Hi Doubledip, There is no slow take off involved in my problem. It absolutely hauls a$$, throttle response and acceleration is excellent but it just holds onto the gears way too long and getting back into it after a shift makes it down shift. Everything I'm describing is part throttle, cruising thru the gears. I'm afraid to mash it since the shift points are already so high.

Also, Please don't take my comment about taking it to a shop the wrong way. I would take this thing in in a heartbeat if I could afford to. Believe me after this project I know how skilled you have to be to get a conversion like this working and how valuable those skills are.

My problem is I didn't go the conventional way due to budget in the first place. Most swappers buy aftemarket harnesses and computers and just hookup the wires as labeled but I thought I would be smart and use the factory fuse box since the engine harness plugged right into it.

I also had to get the trans and transfer case from a different year than the engine and TCM so this may have caused some unforseen compatibility issues that we have been discussing. There is a lot of info out there for those that go aftermarket, but modifying stock stuff is not nearly as common and hard to find anyone that really knows the mechanical and electrical intricacies.

So I successfully got the whole thing working but this trans business has worn me out. I really appreciate your assistance as well!

Doubledip

Sorry for no reply.. been away fom a computer... seen you have possibly found your problem (Hptuners forum) and as i thought seems to be the ISS missing did the OS fix it?.. HP's cant fix that problem as they dont have the settings in it needed...

markeheiden

Hi Double Dip, Problem has been identified as missing ISS in my transmission. My tuner is working on getting a solution. Hopefully I will be throwing dirt roost again soon.

Thanks again for all your support as well!