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Audi TT Car Club 6th Year Anniversary & Membership Discount
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Quattro System
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I have been doing a lot of research, AWD in this vehicle is not 100% all time, and it does work when needs more traction. At speeds over 50 miles per hour the car becomes FWD if don't; the other factor is that you have to have the same brand and size tires and do the alignments as schedule or everytime you get new tires. Do some research before running in conclusions.
| Haldex diagnostics and function testing.... |
| Posted by: TTschwing/Modshack on 2006-03-08 06:10:42 Account #: 13940 Advertiser In Reply to: Electrical posted by Quiet sTTorm-TTakes2 on 2005-11-11 06:50:31 |
Function-test of the Haldex coupling.
- Rollout in circle
Aim: Check the function of the coupling and the response on the car. Is to be done on level ground.
1. Drive in circle with minimum turning radius at a speed of about 10 km/h.
Disengage the clutch and close the throttle.
Let the car roll to full stop.
2. Drive in circle with minimum turning radius at same speed as in case 1.
Disengage the clutch and run up the engine to 3000 - 4000 rpm.
Let the car roll to full stop.
* If the coupling is working the car will stop in about half the distance in case 2 compared with case 1.
* If there is no difference in the two cases there is a malfunction of the coupling. The problem could be caused by the coupling or by missing signals from the car. A further inspection has to be done to be able to determine the cause of the malfunction.
* If a noise from the HLSC is noticed when turning or driving in circles the oil in the coupling is damaged. The damage can be caused by overheating or by water in the oil.
- AWD test on car lift. (all wheels free to turn.)
Aim: Check the function and the control of the coupling.
1. Pull the handbrake.
Disengage the clutch.
Start the engine.
Put the gearbox in 2:nd gear.
Let the engine idle.
Engage the clutch.
* Engine is supposed to stop when the clutch is engaged. (HLSC controlled as in handbrake start.) If engine do not stop, disengage the hand brake immediately. Otherwise there is a risk of seriously damage on the HLSC.
2. Disengage the handbrake.
Disengage the clutch and start the engine
Put the gearbox in 2:nd gear.
Let the engine idle.
Engage the clutch. At least one front wheel and one rear wheel is supposed to turn.
Pull the handbrake for 2 seconds.
* Front wheel is supposed to turn while the rear wheels are supposed to stop when the brake is pulled. Engine is supposed to run all the time. (HLSC controlled as in handbrake turn.) Don't exceed the 2 seconds or repeat the test for more than 5 times during a 5-minute period. Otherwise there is a risk of seriously damage on the HLSC.
Trouble shooting on HLSC
- Visual inspection
Aim: Check for leakage and external damage that affects the function on the HLSC. Is to be done with the car on a car lift.
1. Check for oil-leakage from the coupling. If leakage is found, check oil level at the level screw on the left side of the coupling.
2. Check wires and connecting sockets.
T8 - Socket between car and control unit
T8/1, Red = Ign.
T8/2, Black = Gnd.
T8/3, White = BLS
T8/4, Blue = HBLS
T8/5, Brown = K-line
T8/7, Blue/Grey = CAN low
T8/8, Blue/Orange = CAN high
T2 - Socket between control unit and feeder pump
T2/1, Yellow = Pump 1
T2/2, Yellow/Black = Pump 2
- Signals
Aim: The following signals from the car affect the function of the HLSC. If one or more of the signals is missing or false the function of the HLSC will be reduced.
Bremse 1; BLS, BTS, ABS
Bremse 3; VR, VL, HR, HL
- Rollout in circle
Aim: Check the function of the coupling and the response on the car. Is to be done on level ground.
1. Drive in circle with minimum turning radius at a speed of about 10 km/h.
Disengage the clutch and close the throttle.
Let the car roll to full stop.
2. Drive in circle with minimum turning radius at same speed as in case 1.
Disengage the clutch and run up the engine to 3000 - 4000 rpm.
Let the car roll to full stop.
* If the coupling is working the car will stop in about half the distance in case 2 compared with case 1.
* If there is no difference in the two cases there is a malfunction of the coupling. The problem could be caused by the coupling or by missing signals from the car. A further inspection has to be done to be able to determine the cause of the malfunction.
* If a noise from the HLSC is noticed when turning or driving in circles the oil in the coupling is damaged. The damage can be caused by overheating or by water in the oil.
- AWD test on car lift. (all wheels free to turn.)
Aim: Check the function and the control of the coupling.
1. Pull the handbrake.
Disengage the clutch.
Start the engine.
Put the gearbox in 2:nd gear.
Let the engine idle.
Engage the clutch.
* Engine is supposed to stop when the clutch is engaged. (HLSC controlled as in handbrake start.) If engine do not stop, disengage the hand brake immediately. Otherwise there is a risk of seriously damage on the HLSC.
2. Disengage the handbrake.
Disengage the clutch and start the engine
Put the gearbox in 2:nd gear.
Let the engine idle.
Engage the clutch. At least one front wheel and one rear wheel is supposed to turn.
Pull the handbrake for 2 seconds.
* Front wheel is supposed to turn while the rear wheels are supposed to stop when the brake is pulled. Engine is supposed to run all the time. (HLSC controlled as in handbrake turn.) Don't exceed the 2 seconds or repeat the test for more than 5 times during a 5-minute period. Otherwise there is a risk of seriously damage on the HLSC.
Trouble shooting on HLSC
- Visual inspection
Aim: Check for leakage and external damage that affects the function on the HLSC. Is to be done with the car on a car lift.
1. Check for oil-leakage from the coupling. If leakage is found, check oil level at the level screw on the left side of the coupling.
2. Check wires and connecting sockets.
T8 - Socket between car and control unit
T8/1, Red = Ign.
T8/2, Black = Gnd.
T8/3, White = BLS
T8/4, Blue = HBLS
T8/5, Brown = K-line
T8/7, Blue/Grey = CAN low
T8/8, Blue/Orange = CAN high
T2 - Socket between control unit and feeder pump
T2/1, Yellow = Pump 1
T2/2, Yellow/Black = Pump 2
- Signals
Aim: The following signals from the car affect the function of the HLSC. If one or more of the signals is missing or false the function of the HLSC will be reduced.
Bremse 1; BLS, BTS, ABS
Bremse 3; VR, VL, HR, HL