97+ tcu info??

[Flashback98]

Anyone have a diagram or info for 97+ tcu? 99 xj Trying to do the 1-2 manual mod having trouble seeing which color is for the 2nd gear solenoid. Thanks.

 

[Flashback98]

Also reading some info that’s telling me this is ill advisable on the 97 and newer. Any input?

 

[lawsoncl]

The change was in 98+. Yes, you will likely through a check engine code when the TCU senses the transmission is in the wrong gear, as it compares the input and output speeds.

There are three solenoids.
Shift Solenoid A, pin 12, white
Shift Solenoid B, pin 13, orange/white
T/C Lockup Solenoid, pin 11, darkblue/white

1st Gear, Solenoid A powered
2nd gear, Solenoids A&B powered
3rd gear, Solenoid B powered
4th gear, neither solenoid powered

 

[Flashback98]

The change was in 98+. Yes, you will likely through a check engine code when the TCU senses the transmission is in the wrong gear, as it compares the input and output speeds.

There are three solenoids.
Shift Solenoid A, pin 12, white
Shift Solenoid B, pin 13, orange/white
T/C Lockup Solenoid, pin 11, darkblue/white

1st Gear, Solenoid A powered
2nd gear, Solenoids A&B powered
3rd gear, Solenoid B powered
4th gear, neither solenoid powered

Thanks for response. Any idea what color the power wire is for tcu? I know in older models it was yellow. Not really concerned with check engine light just curious if there’s any other issues I’d come across. Saw some old posts saying could cause trans to shift funny in the 98+

 

[lawsoncl]

Power is Dark Blue with White stripe, pin 26 on the bottom corner

CAV CIRCUIT FUNCTION
1 – –
2 – –
3 – –
4 T14 20LG/WT OUTPUT SHAFT SPEED SIGNAL
5 – –
6 D2B 20WT/BK CCD BUS (–)
7 D1B 20VT/BR CCD BUS (+)
8 – –
9 T3 18VT RANGE SENSOR D3
10 – –
11 T22 20DB/WT TRANS SOLENOID (LOCK UP)
12 T19 20WT TRANS SOLENOID A
13 T60 20OR/WT TRANS SOLENOID B
14 D21C 20PK DATA LINK TRANSMIT
15 – –
16 K167E 20BR/YL SENSOR RETURN
17 K22 20OR/DB TPS TO TCU
18 L10A 18BR/LG BACKUP LAMPS
19 – –
20 – –
21 T42 18VT/WT RANGE SENSOR L
22 T1 18LG/BK RANGE SENSOR D
23 K29A 20WT/PK STOP SWITCH-NORMALLY CLOSED
24 Z12A 18BK/TN GROUND
25 M1D 20PK UNDERHOOD LAMP & IGNITION OFF DRAW
26 F12A 18DB/WT IGNITION (RUN/START)

 

[wbnickens]

https://imgur.com/a/37RRID3

 

[lawsoncl]

I'm thinking that oem white from the TCU should actually be orange/white which is solenoid 2 (pin 13). The blue is the db/wh ignition power on pin 26. Clever using the NSS signal as a relay trigger.

 

[wbnickens]

My notes in the 2000 FSM schematic indicates that the OEM white wire for solenoid A control (TCM pin 12) goes to trans valve body solenoid 2. Confusing right! I designed this back in 2009 and don’t remember how I discovered that.
The custom blue wire is spliced into VT/WT wire (1-2 gear) from the trans range sensor (trans shifter) to the TCM pin 21.
No check engine light.
Warning- If the DPDT switch is in the 1st gear position and the trans shifter is moved from 3rd gear to 1st-2nd gear the trans will go straight to 1st gear!

 

[wbnickens]

I think a moderator may want to move this thread to modified tech.