Traction Control and Rear Diff Lock

[pampaskat]

Hi all,

Has anyone figured out how to keep traction control active when locking the rear diff on the NS Paj? I suppose there would be some signal wire from the rear diff lock ECU to the traction control ECU that tells the latter when to quit. I also suppose that one would be able to install a switch in this line to interrupt this flow of information at will, because sometimes it is very useful to be able to turn off the traction control system.

Any ideas?

Regards

Gerrit

[pittsy]

Hi all,

Has anyone figured out how to keep traction control active when locking the rear diff on the NS Paj? I suppose there would be some signal wire from the rear diff lock ECU to the traction control ECU that tells the latter when to quit. I also suppose that one would be able to install a switch in this line to interrupt this flow of information at will, because sometimes it is very useful to be able to turn off the traction control system.
Any ideas?

Regards

Gerrit

Maybe you could wire in a separate switch with its own power supply, that way it could be used with or without traction control. I'm assuning that they are all the same, my diff lock works in 4HLc and the traction control didn't appear to switch off, not sure if this would be correct or not.

Has anybody else found this???????

Sorry to get of the subject bud, but how do you find the Geolanders???

[pampaskat]

Sorry to get of the subject bud, but how do you find the Geolanders???

I am pretty happy with the AT-S's at the moment. I have only had them for about 16000 km, but it is pretty clear that they are in a different league than the GO-39s that were originally on the car. On the bitumen they are quiet and seem to grip well in wet and dry weather, while they have performed pretty well off the black stuff too. I have used them in sand, mud (not extreme stuff, though) and on rocky/gravelly terrain and am well pleased. They don't seem to generate the heal-and-toe wear pattern like the older Yokohama AT used to either.

Regards

Gerrit

[pittsy]

Maybe you could wire in a separate switch with its own power supply, that way it could be used with or without traction control. I'm assuning that they are all the same, my diff lock works in 4HLc and the traction control didn't appear to switch off, not sure if this would be correct or not.

Has anybody else found this???????

Sorry to get of the subject bud, but how do you find the Geolanders???

Sorry have to correct myself, diff lock turns off traction cont. etc in 4HLc also.

[liam]

GENERAL INFORMATION


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FEATURES

The Active Stability and Traction Control System (ASTC) has been installed.


The Active Stability and Traction Control System responds to driving conditions and controls the braking mechanisms of all four wheels independently by separately applying the brakes for each wheel. It also governs the engine output to manage spin, drift-out, and other forces when driving within certain limits.

The Active Traction Control System independently controls the braking mechanisms of the four wheels. It also governs the engine output and controls the wheel slip ratios to manage accelerations during starting on slippery surfaces. It also improves driving ability on poor surfaces by applying differential lock effect.

Fail-safe function ensures safety is maintained

Improved serviceability

To shorten the lines and enhance data transmission reliability, communication with other ECU is performed over a CAN (Controller Area Network).
note

For further details on CAN communication, refer to GROUP 54D, CAN .

The ASTC-ECU controls ABS as well.




--------------------------------------------------------------------------------

CONSTRUCTION DIAGRAM



Component
Number
Outline of functions

Sensor

Wheel speed sensor
1
Sends alternating current signals at frequencies which are proportional to the rotation speeds of each wheel to the ASTC-ECU.

Stoplamp switch
2
Sends a signal to the ASTC-ECU to indicate whether the brake pedal is depressed or not.

G and yaw rate sensor
3
It detects the lateral acceleration and longitudinal acceleration and yaw-rate of the vehicle. Then it sends a signal through the CAN bus line to the ASTC-ECU.

Steering wheel sensor
4
Detects the steering wheel angle, and sends a signal to the M-ASTC-ECU through the CAN bus line.

ASC OFF switch
5
Sends a signal to the ASTC-ECU to turn on and off the active stability control.

2WD/4WD detection switch
6
Detects the transfer driving mode.

4LLc detection switch
7

Centre differential lock detection switch
8

2WD detection switch
9

4H detection switch
10

Rear differential lock switch*
11*
Sends the rear differential lock state to ASTC-ECU.

Master cylinder pressure sensor
12
Informs the ASTC-ECU whether the brake pedal is depressed (the same function as a stop lamp switch)

Actuator
Hydraulic unit
13
Drives the solenoid valves according to signals from the ASTC-ECU in order to control the brake hydraulic pressure for each wheel.

Valve relay
14
It is turned on/off by the signal from the ASTC-ECU. ASTC-ECU shuts down the solenoid valves by this relay, when malfunction is detected.

HBB motor relay
15
Is turned on by the signal from the ASTC-ECU, and energizes the motor in the HBB.

HBB buzzer
16
Sounds by a signal from the ASTC-ECU to inform the driver of the Active Traction Control system overheat. HBB buzzer is also used for accumulator low-pressure warning.

Brake warning lamp
17
Illuminates in response to signals from the ASTC-ECU when a problem which affects the HBB and EBD function develops in the system.

ABS warning lamp
18
Illuminates in response to signals from the ASTC-ECU when a problem develops in the system.

Active stability control indicator lamp
19
It receives a signal from the ASTC-ECU, and indicates ASC or ATC system operating and system status.


Flashes: ASC or ATC system operating.

Illuminate with buzzer: ATC system is in overheat protection mode.

Only illuminate: ASC or ATC system has malfunction.


Active stability control-OFF indicator lamp
20
Receives a signal from the ASTC-ECU, and flashes or illuminates to inform the driver that the system is not operating or defective.

4WD indicator lamp
21
Receives a signal from the ASTC-ECU, and flashes to inform the driver which wheel is under the active traction control.

Diagnostic connector
22
Sets the diagnostic trouble codes and allows communication with the M.U.T.-III.

Engine-ECU <3200>
23
Receives a signal from the ASTC-ECU to control the engine output.

Engine-A/T-ECU <3800>
24

Active Stability Control and Active Traction Control System control unit (ASTC-ECU)
25
Controls actuators (described above) based on the signals coming from each sensor.

Controls the self-diagnosis and fail-safe functions.

Controls the diagnosis function (M.U.T.-III compatible).

note *:Vehicles with rear differential lock (Option)

[pampaskat]

Thanks for the info, Liam. Where did you get that from? Do you perhaps have the relevant parts of the wiring diagram?

Is the rear differential lock switch that is referred to above the actual control switch in the cab or the diff lock state detection switch at the rear diff?

Thanks again,

Regards

Gerrit

[liam]

traction control

see if this helps see attached pic
cheers liam if you need more info just let me know got info of cd i have that i got from work i work for mits

[mrbitchi]

As I understand it traction control won't work when the diff lock is engaged. Basically TC works by controlling the difference in wheel speed across an axle, by braking the spinning wheel. With diff locks engaged there will be no difference in wheel speed across the axle, hence no TC action.

[pampaskat]

Thanks for the diagram, Liam. It is clear from your diagram that the traction control ECU gets its info from the diff lock detection switch at the diff.

mrbitchi, you are correct that no traction control action would be possible on an axle with a locked diff, but remember that the front diff is still open. It would be great to have the traction control system available to prevent front axle spin-out while having mechanical diff locks in the center and rear. With only the front axle to worry about, the traction control system should also be able to function quite a bit longer before overheating and turning off in the interest of self preservation.

[mrbitchi]

Me thinks that in this situation TC would be of minimal assistance. To make the TC activate you'd have to have one front wheel lose traction and commence to spin. Bear in mind that at the same time 50% of your engine power is going to the rear wheels. Both rear wheels would have to loose traction, as well as one front wheel. Time for the winch

If you're worried about getting that last bit of traction out of your beast, fit a front locker as well.

[Enric]

If you're worried about getting that last bit of traction out of your beast, fit a front locker as well.

I think it's cheaper to put a switch than a front diff locker :-)

[mrbitchi]

I think it's cheaper to put a switch than a front diff locker :-)

True but if the switch does nothing...

[pampaskat]

Me thinks that in this situation TC would be of minimal assistance. To make the TC activate you'd have to have one front wheel lose traction and commence to spin. Bear in mind that at the same time 50% of your engine power is going to the rear wheels. Both rear wheels would have to loose traction, as well as one front wheel. Time for the winch

I have been in the following situation many times, especially on steep climbs with some axle twisters: You end up being imobilized and cross axled with good grip at one front wheel and the diagonally oposite rear. Both rear wheels are forced to rotate together with a locked rear diff, but only one has good grip. At the front, the wheel with least grip spins, thus transferring very little tractive effort while the open diff ensures that an equally small amount of tractive effort is transmitted by the front wheel with good grip (this wheel stops turning). A traction control system working on the front axle (or a front diff lock) can cause a substantial increase in the total tractive effort by forcing the front wheels to rotate together, thus effectively harnessing the traction available at the front wheel with good grip. The front locker is the more effective one in terms of traction, of course, as you said , but traction control is only active when needed (some would say just after it is needed) so it interferes less with steering.

Just as an aside; An open diff splits torque 50:50 (nominally) and not power. Power is the product of torque and rotational speed. A wheel that is not turning can not transmit power although it can transmit torque.

In the scenario outlined above if the center diff is locked, the front and rear driveeshafts are forced to rotate at equal speeds, but the the torque is not split 50:50, but rather according to the resistance to rotation at each axle. Almost all the torque will be transmitted by the rear axle in the scenario above if a wheel on the front axle is spinning out.

Hope that all makes sense...