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Wiring & Pinouts guides and mods

Roadster Transmission Pin Out

Modification Details




Transmission (Gear Box) Connections

If you are experiencing the 3 Bar error on the speedo display, there is a very high chance
that the issue lies with the wiring loom to actuators and sensors that control the gearbox.

A visual inspection of the wiring loom often shows up the issue but not always.

Movement of the wires can cause cracks in the sheathing which allows water in.
The water and electricity increases the speed of corrosion to the copper core of the wire.

However, this damage may not be visible from the outside.

Continuity Testing

The best way to test a wire's integrity is to use a multimeter on continuity mode.
This is where you hold a probe at each end of the wire and the meter will tell you if there is a connection.

Most multimeters will have 2 continuity modes. One will tell you the resistance of the connection
and the other will just beep if it senses a connection. Start with the simple beep mode at first.

Transmission Controller Pin Connection Wire Colour Connects To Purpose
Gear Change Motor 1 Green ECU Plug 2, Pin 3 Motor
2 Green ECU Plug 2, Pin 33 Sensor + (voltage)
3 Yellow ECU Plug 2, Pin 14 Sensor B Output
4 White ECU Plug 2, Pin 51 Sensor - (ground)
5 Yellow ECU Plug 2, Pin 15 Sensor A Output
6 Blue ECU Plug 2, Pin 1 Motor
Clutch Actuator 1 Green ECU Plug 2, Pin 43 Sensor - (ground)
2 Yellow ECU Plug 2, Pin 24 Sensor B Output
3 Yellow ECU Plug 2, Pin 4 Motor
4 Yellow ECU Plug 2, Pin 23 Sensor A Output
5 Blue ECU Plug 2, Pin 75 Sensor + (voltage)
6 Yellow ECU Plug 2, Pin 5 Motor
Gear Position Sensor 1 Blue ECU Plug 2, Pin 79 Sensor + (voltage)
2 Yellow ECU Plug 2, Pin 19 Sensor Output
3 White ECU Plug 2, Pin 60 Sensor - (ground)
Gearbox RPM Sensor 1 Red ECU Plug 2, Pin 11 Sensor + (voltage)
2 White ECU Plug 2, Pin 30 Sensor Output

Continuity Tested OK

OK, put the multimeter in the other continuity mode or resistance measuring mode.
Test all of the connections again but pay close attention to the figures show on the meter.

It's very possible to have a wire that's corroded enough to create high resistance but pass some voltage.
A tiny pass through of voltage by the meter will cause the beep continuity mode to make a noise.

However, if the wire is corroded and resisting the voltage, it may not be enough to run the motor or sensor correctly.

Jot all of the resistance figures down. If any are particularly high, you may have a problem on that wire.

Stress Testing

If you don't have a multimeter (they are very cheap so you should own one) then you can make a tester.

If you get a 12v battery and 12v bulb, or a 9v PP3 type square battery and a 9v bulb (don't use an LED),
You can put the wire that you are testing into a circuit and pass the voltage to the bulb.

Because of the amperage required, if there is a resistive point in the wire, the bulb should be more dim.
Alternatively, the wire could get hot at the corroded point and melt the sheathing.

If you have a thermal imaging camera, you can see the problem.

Fixing A Corroded Wire

Once you have discovered the problem wire, cut the wire and splice in a replacement.
Make sure to protect the connections with heatshrink and run the new cable safely.

 

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