Trans controller wiring MS2 on a V3 board

(C) James Murray Oct 2007, 2008, 2009

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As the V3 board is DIY-able, it is easier to make a few changes on the board to support the transmission control application. (As a result the wiring is different to the Microsquirt application which uses some external components.)

DB37 pin number

Signal name

Function

2

VR-

VSS negative (rear /side of trans or transfer case)

24

VR+

VSS positive (rear /side of trans or transfer case)

37

FP

Solenoid A

30

IDL

Solenoid B

36

IGN

3-2 Solenoid (4L60E only)

32

INJ1

TCC solenoid (LU)

34

INJ2

EPC solenoid

23

EGO

TPT pin A

5

SPR3

TPT pin B

6

SPR4

TPT pin C

1

GND

Trans and engine temp sensor ground if not sharing with ECU.

20

MAT

Trans temp sensor

If non-GM then adjust R4 as required..

7,8,9,10

GND

Connect to a good ground location

28

+12V

Connect to a fused 12v supply live when ignition is on

27

IAC1B

Brake switch signal. Connect this to ground when brake pedal is pressed, may need to use a relay to achieve this.

3,4

SPR1,SPR2 (CANH,CANL)

Optional, connect to MS2 CAN network to fetch RPM, TPS and engine temp from the main ECU. If not using CAN you can leave these disconnected.

25

IAC1A

Engine speed signal. Connect to tacho, coil or crank sensor.

21

CLT

Engine temp sensor – NOTE if sharing sensor with ECU then R7 should be removed.

If non-GM then adjust R7 as required.

26

VREF

If standalone TPS is used, connect to TPS. DO NOT CONNECT if sharing TPS with another ECU.

27

TPS

TPS signal “middle wire” (0-5v input).

Connection not required if using CAN.

18

GND

If standalone TPS is used, connect to TPS. DO NOT CONNECT if sharing TPS with another ECU.



Only required if using CAN

Not required if using CAN






The following internal wiring modifications are required.

  1. The trans control application does not require the active flyback circuits or FP, IDL limiting circuits, so the following components can be omitted.

  2. Omit transistors: Q9, Q10, Q12, Q13, Q14, Q15, Q19, Q20

  3. Omit resistors: R30, R31, R32, R34, R35, R36, R37, R38

  4. If omitted, R37 and R38 should be replaced with jumpers.

  5. The LEDs are not used by the code, so R24,R25, R26, R27, R28, R29 ; Q6, Q7, Q8 ; D14, D15, D16 can be omitted.

  6. Advanced, optionally could omit D5, Q3, R18, D6, D7, Q11, R33, D20 and use 1N4001 to 12V on each output.

  7. The FP and IDL output transistors are borderline on the current capacity for the solA and solB solenoids in the transmission, you can jumper R39 and R40 and hope. OR, the safer option is to replace these two transistors with TIP121 mounted on the heatsink bar with a mica insulation kit as shown.

  8. Remove R10 and replace with diode 1N4001 (or equivalent) with band to the right.

  9. Remove R11, leave the space open.

  10. Install three diodes 1N4001 on the proto area.

  11. Connect the non-band sides of the diodes to JS5, JS4, JS11 as shown.

  12. Connect the band sides of the diodes to SPR3, SPR4, IAC1B as shown.

  13. Connect VRIN to TACHSELECT

  14. Connect VROUT to TSEL

  15. Connect OPTOIN to IAC1A

  16. Connect OPTOOUT to JS10

  17. 4L60E. Install a 330R resistor in the proto area.

  18. 4L60E. Connect one end of the resistor to 'top' of R26 as shown.

  19. 4L60E. Connect the other end of the resistor to IGBT IN as shown.

  20. 4L60E. Install VB921 / BIP373 / TIP121 into Q16.

  21. 4L60E. Jumper IGBTOUT to IGN

  22. 4L60E. Install R43 or jumper.

  23. If sharing engine temp sensor with ECU then remove R7.

  24. If using CAN to fetch TPS/RPM/Engine temp from MS2 ECU, then run jumpers from CANH/L at CPU to CANH/L at DB37

  25. If using CAN for those inputs, the following components may be omitted : C6, C7, C8, C9, C11, C12, C30; R8, R9, R12, R13; D1, D2

  26. The MAP sensor is optional. If not used, the following components can be omitted : C2, C3; U2; R2

To CAN or not to CAN?

The CAN communications is a two wire hookup to fetch engine sensor data from a master MS2 or MS3 ECU. It is simple and it works. If you do use CAN then you do not need to duplicate the wiring to TPS, RPM or engine CLT sensors.

If using a non-MS2 master ECU then skip CAN and do piggyback these inputs.

Transmission connector

The following diagrams and pinout lists were taken from the yahoo Megashift group and corrected from service data. The 4L80E for sure is looking into the transmission, so the plug is reversed.







Early 4L80E connector

1993 up 4L80E connector

4L60E connector





Function

DB37 pin

Early 4L80E

Late 4L80E

4L60E

Sol A Switched Gnd

37

A

A (Light Green)

A

Sol B Switched Gnd

30

B

B ( Yellow/Black)

B

+12 Power

fused 12v

C & K

E (Pink/Black)

E

Press Sw A (Pin A)

23

D

N (Pink)

N

Press Sw B (Pin B)

5

E

R (Blue)

R

Press Sw C (Pin C)

6

F

P (Red)

P

Temp Sensor GND

19

H

M (Purple)

M

Temp Sensor

20

G

L (Black/Yellow)

L

LU Sol Switched Gnd

32

J

S (Brown/Black)

T

EPC +12V

fused 12v

L

C (Red/Black)

C

EPC Switched Gnd

34

M

D (Grey/White)

D

3-2 solenoid switched Gnd

36

n/a

n/a

S

Lock up feel solenoid switched Gnd (Cadillac only?)

Not implemented

n/a

n/a

U



Wire colours from a random 4L80E loom.

Note, the transmission requires a fused 12V supply. Suggest one 10A fuse to supply both +12V and EPC. The 4L60E may require a 15A fuse due to the additional solenoid.

The Megasquirt also requires its own fused supply 1-5A fuse preferred.

Last updated: 9th February 2009

Email: jsm@jsm-net.demon.co.uk