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TCU differences - HO > Renix

ParadiseXJ

NAXJA Forum User
Other than the obvious differences in the color of the connecters (one is light gray 87-89, the other is green 91-?) for the different TCU's can anyone tell me what the difference is in the two TCU's. Are the pins in different order??

http://www.ebay.com/...971f26b&vxp=mtr

http://www.ebay.com/...00f740d&vxp=mtr

If my Renix truck has an HO transmission...does it use a Renix TCU with a Renix wire harness OR does the HO tranny use an HO TCU with an HO harness. Or does it matter??
 
Other than the pin outs and the connectors the main difference in the Renix TCU is autonomous and the later TCU has a connection to the PCM. I have no idea what no inputs from the PCM will do to the later TCU programming and/or function.

http://www.naxja.org/forum/showthread.php?t=1053970

A 97 and later AW4 has a different reed switch (speed sensor).
 
Fixed!!

The HO tranny in the Renix Jeep...needs a Renix TCU.

This damn thing is FINALLY fixed!!!

party1:
 
You're shitting me!!

I wouldn't do that. You have too much invested in my problems. It is driving like a frikken dream. Fixing just about everything trying to nail down this problem has it's benefits.

:party::party:

This what's goin' on here tonight!! Thanks for all your help and problem solving!!
 
The 97+ TCU will do its thing standalone too, it only connects to the data bus for debugging and so the ECU can ask it if it is OK and turn the MIL on if it doesn't respond or says it has a fault of some sort.

The HO TCU and Renix TCU use the same TPS signal? I knew the RENIX uses a dual TPS and wasn't sure if the ECU signal flipped from RENIX to OBD1 or if the TCU one did, good to know.

I am guessing it was a brake light switch issue, because none of the sensors or actuators other than that should be different. NSS is the same 87-96, you say TPS signal is the same, trans solenoids should be the same 87-96 and are electrically the same even later... I am all out of ideas as to why it would matter.

Might be pinout, I don't know that much about RENIX TCU pinouts.
 
Renix TCU works like an HO TCU and TPS.

The reason there were 2 connectors on a Renix TPS is that the "engine" side and "trans" side worked opposite of each other.
Engine side reduced in voltage as the throttle was opened.
Trans side increased in voltage ouput as throttle was opened ust like the Trans side and an HO TPS.
 
I'm out of my depth here, so if I'm wrong correct me. The late TCU has no direct TPS hookup, the signal is passed through the PCM and my butt dyno experience tells me that the through PCM to TCU (TPS values) are massaged on the way to the TCU. I've always assumed the different shift points in the HO TCU were partially because of the PCM (programming) and not totally due to different programming in the later TCU.
I could be wrong, like I said just an assumption. Some day when I have nothing better to do, I may hook up a couple of volt meters, one to the HO TPS and another to the PCM to TCU wire and see if the signals match or not.


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Nope... even on the late models the TCU still gets a hardwired TPS signal, it's the orange/dark blue wire on pin 17. Common misconception though, tons of people think it gets that info through the CCD bus from the ECU.

It also still has hardwired signals for the NSS, OSS, ISS (98+ only), brake light switch, and an ISO9141 K-line signal to the OBD2 port for debug/reflashing.
 
I'm out of my depth here, so if I'm wrong correct me. The late TCU has no direct TPS hookup, the signal is passed through the PCM and my butt dyno experience tells me that the through PCM to TCU (TPS values) are massaged on the way to the TCU. I've always assumed the different shift points in the HO TCU were partially because of the PCM (programming) and not totally due to different programming in the later TCU.
I could be wrong, like I said just an assumption. Some day when I have nothing better to do, I may hook up a couple of volt meters, one to the HO TPS and another to the PCM to TCU wire and see if the signals match or not.


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The D1 thru D3 pins on the Renix TPS, go straight to the adjustable TPS. The HO wires (Orng/Dk Blu, Blk/Lt Blu) go to the non-adjustable TPS thru the PCM. I had the harness with the 3 wires (Red, Gry/Bk, Orng/Brn) all hooked up so I figured I was good...until I started thinking about the different connectors and their colors (viz a viz different set-up). :idea:

I really have to thank ALL you guys, and some of the guys over on CC for leading me by the hand through this, it's been quite a work in progress (and education). I do NOT have to work on my truck this weekend (and I'm not gonna)!!
 
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They don't actually go THROUGH the PCM, it just taps into the same feed. The PCM supplies reference voltage and ground to the TPS, though.
 
They don't actually go THROUGH the PCM, it just taps into the same feed. The PCM supplies reference voltage and ground to the TPS, though.

Thanks I finally figured out the TPS in the HO goes through a splice to the PCM and the TCU. I always assumed, by the misleading wiring diagram I looked at, that the TPS in and outed at the PCM to the TCU (wrong).

The newer type wiring diagrams for later model XJ's (94 and newer I think) are broken down into a hundred separate diagrams and need a lot of cross referencing and page turning, it gets confusing sometimes and makes grasping the big picture a chore.

I've never had to do a lot of troubleshooting for the transmission, a few ground issues or dirty connector issues and one transmission my daughter grenaded (shifting to park or reverse at 45 MPH, not sure which she did, is to be avoided).
 
OBD1 FSM wiring diagrams do really really suck, I agree. 96 are half and half, 97+ are much better. I haven't ever seen a RENIX FSM diagram, just the terrible ones in the Haynes and that 88 wiring diagram pdf that everyone passes around like it's gospel which then turns out to be absolutely worthless.
 
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