Maybe there needs to be a minimum speed for the traction control to work. Just like ABS which uses the same sensors and switches off at around walking pace on most cars.
Whilst 4Wdriving in the Pilbara (Hickman crater) I was following me mate up a creek bed and he bellied out his D3 TDV6 on a large sand hump..
Me in my 88RRC observed the following
When trying to extract himself , the RHF wheel was in the air 100 mm and the LHF was still on the sand .Both rear wheels were dug into the base of the mound.
So there it was with the RH front and the LH rear spinning slowly and the other pair of diagonal opposite remaining dead stationary.
Now the issue is , is this what should have happened ?, as I thought the "Traction control ?would use the ABS system to brake the Spinning wheels and transter some torque to the stationary wheels. Obviously if it was "bellied" out then it probably made no difference if all 4 wheel had equal drive torque
Now between the "Terrain Response" the HDC,DSC,EMS.TCS,TCM,ABS,(and half a dozen more acronyms for various systems !!) I didnt think what I was seeing was possible.
He claims he was in "Rock crawl " mode (why in the sandy creek bed I dont know , but thats the Pilbara !)
What I reckon is without a speed reference that actually indicates that the car is moving the "Brain" thinks its in some other circumstance.
I didnt notice it going into extended mode either .
Ive just bought a D3 TDV6 (which only SWHMBO will drive )'
It would be good to Know that what I observed is standard procedure
Last edited by 400HPONGAS; 18th January 2011 at 10:21 AM. Reason: Carnt spel
Maybe there needs to be a minimum speed for the traction control to work. Just like ABS which uses the same sensors and switches off at around walking pace on most cars.
It should have gone into extended mode by itself and then he could have pushed it into super extended by pushing the brake and the height lever for 3 seconds.
OKay then Dougal , so hypothetically , if he was to rev it up abit there would be a point at which the ABS reverses itself (as an easy explanation)and becomes Traction control ?
I wonder if there is a good Logic chart of the pre-emptive and reactive Modes as determined by the setting of the "Terrain Response" Now that would be interesting
Straight from the Horses mouth (this for a Disco 3 )
ETC
ETC attempts to optimize forward traction by reducing engine torque or braking a spinning wheel until it regains grip.
ETC is activated if an individual wheel speed is above that of the vehicle reference speed (positive slip) (AH HA ! what is this reference speed ?)and the brake pedal is not pressed.
The spinning wheel is braked, allowing the excess torque to be transmitted to the non spinning
wheels through the drive line. If necessary, the ABS module also sends a high speed CAN bus message to the ECM to
request a reduction in engine torque.
Torque reduction requests are for either a slow or fast response: a slow response
requests a reduction of throttle angle (4.0L and 4.4L only); a fast response requests an ignition cut-off (4.0L and 4.4L) or a
fuel cut-off (2.7L Diesel).
When the DSC function is selected off with the DSC switch, the engine torque reduction feature is disabled.
On vehicles with an automatic transmission, when the ETC function is active the ABS module also signals the TCM to
prevent gear shifts
The anti-lock control - traction control system is based on the 4 channel Bosch 8.0 system and provides the following
brake functions:
Anti-lock Braking System (ABS).
Corner Brake Control (CBC).
Dynamic Stability Control (DSC).
Electronic Brake-force Distribution (EBD).
Electronic Traction Control (ETC).
Emergency Brake Assist (EBA).
Engine Drag-torque Control (EDC).
Hill Descent Control (HDC).
So theres alot more to it than the defender and D2 systems especially when you chuck in all the pre-emptive "Terrain Response" Algorithms
Still it brings me back to the my original observations , and Im none the wiser if what I saw was normal or something wasnt working the way it should .
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