TC not functioning correctly

[glenhendry]

Yesterday I hit some pretty steep trails inland from the Gold Coast, and the P38 performed very well. She heavily impressed the Hilux driver riding shotgun.

However on one diabolical hill that I couldnt get up, despite repeated attacks on different lines, it was noted that the front right wheel was not spinning despite moderate throttle and tyre smoke and dirt flying everywhere from the other wheels.

I have always thought that the TC was working fine, and have not had any fault codes or dash lights to tell me different. How do I diagnose if there is an ABS sensor that is failing to detect that one wheel isnt spinning in order to apply the brake on the other side?

[Pete38]

What year model? Pre the bosch upgrade (before late '99 I believe) they only had traction on the rear.

[glenhendry]

Ooops, all that information was securely in my sig, which seems to have disappeared. Sorry.

It is a 2000MY HSE 4.6. GenIII Arnott. LPG. 31" GY Duratracks.

[Pete38]

Oh OK. So you have traction all round then.

I've taken mine up many a steep and challenging slope with slippery surfaces and lifting wheels on climbing rocks...... And it does tend to not spin the grippy wheel sometimes. The traction works well to a point, and then has those moments of me thinking "should I go buy that locker" for those rare moments the p38 actually has to take multiple goes to find the best line.

95% of the time I like traction but some occasions I'd like to compliment it with a locker on the rear... But that a whole other topic I guess and won't hijack your thread any more :)

[Hoges]

Yesterday I hit some pretty steep trails inland from the Gold Coast, and the P38 performed very well. She heavily impressed the Hilux driver riding shotgun.

However on one diabolical hill that I couldnt get up, despite repeated attacks on different lines, it was noted that the front right wheel was not spinning despite moderate throttle and tyre smoke and dirt flying everywhere.

I have always thought that the TC was working fine, and have not had any fault codes or dash lights to tell me different. How do I diagnose if there is an ABS sensor that is failing to detect that one wheel isnt spinning in order to apply the brake on the other side?

I'm not sure I quite understand...was the front right wheel "airborne"? If so, it was being braked and drive transmitted to the other wheels. Or, was the RHF wheel in contact with the ground and stationary and the LHF spinning?... It's the "spinning" wheel (as distinct from one which is "rotating" at the same rate as the others) to which TC applies braking force in order to transmit drive to the remaining wheels
cheers

[glenhendry]

I'm not sure I quite understand...was the front right wheel "airborne"? If so, it was being braked and drive transmitted to the other wheels. Or, was the RHF wheel in contact with the ground and stationary and the LHF spinning?... It's the "spinning" wheel (as distinct from one which is "rotating" at the same rate as the others) to which TC applies braking force in order to transmit drive to the remaining wheels
cheers

No, the still wheel wasn't airborne. I would have preferred it to be turning. It stayed stopped for a 'long' time while we attempted to get traction and move forward.

It seems that there are additional scenarios I haven't thought about; what does TC do if both front wheels are very light due to the steepness and not getting traction, does it take turns applying brakes on each front side? As one is braked, the other starts to spin, but as soon as it starts to spin faster than the other wheels, then TC halts it and allows power to the other original side?

[benji]

the ABS ECU will only ever want to equalize the speed of the wheels on the same axle - it can't measure torque however, and it's not a very powerfull traction controll like the D2.

If there was a reasonable amount of grip available to the right hand front, the tc may not have been powerfull enought to transfer enough torque to break traction on that wheel.

If the hill was very steep, and it would need to be sky high steep to unweight the front, I imagine the TC would be able to effectively manage the torque transfer.

Another thing that may have happened was to TC turned itself off for a moment so as not to overheat. I've had this happen numerous times before, and it doesn't take that much to get the traction overheat message.

[Keithy P38]

Your brakes are also a factor! Front brakes cop a flogging, spongy pedal, worn pads, all those things will make it harder for the traction control to do its job!

Should do as I've done and lock the rear diff! My P38 is the first up every obstacle on trips. Nothing else I've travelled with (except my old man's twin locked chev diesel defender) even comes close to the capability of the P38!

[Hoges]

The foregoing is yet another reminder that I need to seriously explore the 'outer limits' :twisted:

[glenhendry]

I am definitely interested in a rear locker Keithy. Need to save up first. :)

[Pete38]

Me too. Only 500 pounds plus 80 pound for postage to Sydney for an Ashcroft locker... Sorta hoping the minor cling when going from reverse to forwards occasionally (after a weekend offroad) is the diff so it's a good excuse to put one in :-)

[Keithy P38]

They all do it mate! I think it may be driveline backlash! I have owned two P38's and both did it! Nothing to worry about.

[Pete38]

They all do it mate! I think it may be driveline backlash! I have owned two P38's and both did it! Nothing to worry about.

Oh Ok. Thanks for the peace of mind. I guess after doing a fair amount of low gear/high torque climbing I became more aware of it as it's not overly noticeable or always happen.

[glenhendry]

I confirmed with the Faultmate last night that no faults exist in the ABS/TC systems...

I wonder if we can plonk in a yaw sensor in the centre console and hook up the TC computer from a D3 or L322? Its just an ECU with sensor inputs and control over the ABS???

[Hoges]

Guess we need a software systems integrator...wouldn't happen to know such a person would you:twisted::wasntme: