System Test Overview (ABS and ABS/TC)
System Test Overview (ABS and ABS/TC)
NOTE: The static test must be performed at the start of the system test. Locate and remedy any detected fault. Proceed with the system test only after the static test has been completed successfully.
Necessary Test Steps With ABS/TC 5.3 (4-channel System):
Test step
1 Version coding (start of the test/possible only on vehicles with TC)
2 Static test
3...4 Stop-light switch and terminal 61 signal
5...8 MIL and information lights
9 Intake valve
10 Switch-over valve
11 Return pump operation
12...19 ABS solenoid valves (8 ea./function and incorrect allocation)
20...23 Speed sensors (function and incorrect allocation)
24 Engine speed information to ABS/TC control module
Necessary Test Steps With ABS 5.3 (3-channel System):
NOTE: On vehicles with Solo ABS, the test begins with the static test (test step 2). The test steps in brackets are not necessary (possible only with a 4-channel system).
Test step
1 Not necessary
2 Static test (start of test)
3...4 Stop-light switch and terminal 61 signal
5 ABS MIL
6...10 Not necessary
11 Return pump operation
12...17 ABS solenoid valves (6 ea. / function and incorrect allocation)
18...19 Not necessary
20...23 Speed sensors (function and incorrect allocation)
24 Not necessary
System test ABS and ABS/TC
Test step 1
Select and call up the version Present only for vehicles with Traction Control.
coding. Display according to If necessary, select the Modify coding menu to change the coding.
transmission version (Tiptronic
or manual transmission).
Test step 2
Select and perform the static test. This test checks whether all parts
of the system are present or
whether all electrical components are connected.
Required display: 0 faults. If necessary, remedy any existing fault
before proceeding with the system test.
Test step 3
Call up the Input signals menu Perform troubleshooting analogous to test point 13 (stop-light switch / DTC 4340).
and select the stop-light switch.
Briefly actuate the brake. The
stop-light switch status (open
or closed) is checked. Required
display: Change from "not actuated"
to "actuated".
Test step 4
Call up Input signals menu For troubleshooting, the status of terminal 61 (present or not present) also can be checked in the system Alarm system via the Input signals menu.
and select terminal 61 signal.
Start the engine.
Required display: Signal present (engine
not running: not present). 1. If not present appears in the Tester display with the engine running, call up the system Alarm system and also check the status of terminal 61 there in the Input signals menu.
If the signal is present there, the fault lies in the wire between the ABS control module and the other control module. For trouble-shooting, consult the wiring diagram. If the terminal 61 signal is also not present with the system Alarm system , continue with the next point.
2. Bulb of Generator (MIL) in the instrument cluster faulty. Perform a lamp test (lamp must light up when the ignition is switched on).
3. Check the generator.
Test step 5
Call up the Drive links menu 1. Check bulb
and activate the ABS MIL.
The display must flash. 2. Check wiring between the instrument cluster and control module according to the wiring diagram.
With the ABS/TC, the TC-MIL
is activated as well
Test step 6
Activate the TC-MIL in the Only on vehicles with TC.
Drive links menu. For vehicles with Solo ABS, continue with test step 11.
The display must flash. Troubleshooting analogous to test step 5
Test step 7
Activate the TC information Only on vehicles with TC.
light in the Drive links menu. For vehicles with Solo ABS, continue with test step 11.
Display must flash. Troubleshooting analogous to test step 5
Test step 8
Activate the TC switch Only on vehicles with TC.
information light in the Drive For vehicles with Solo ABS, continue with test step 11.
links menu.
Display must flash. Troubleshooting analogous to test step 5
Test step 9
In the Drive links menu, test Only on vehicles with TC.
function of the intake valve On vehicles with Solo ABS, continue with test step 11.
in the hydraulic unit. Perform troubleshooting analogous to test point 16 (diagnostic trouble code 5260).
Test step 10
In the Drive links menu, test Only on vehicles with TC.
function of the switch-over On vehicles with Solo ABS, continue with test step 11.
valve in the hydraulic unit. Perform troubleshooting analogous to test point 17 (diagnostic trouble code 5265).
Test step 11
In the Drive links menu, Perform troubleshooting analogous to test point 12 (return pump fault / DTC 4266).
activate the return pump.
Return pump runs audibly. If necessary, open the front lid in order to hear the pump run.
Test steps 12 - 19
In the Drive links menu, Test step 12: Maintain pressure, front left
check the inlet and outlet
ABS solenoid valves in the Test step 13: Reduce pressure, front left
hydraulic unit for function
and incorrect allocation. Test step 14: Maintain pressure, front right
Rotate all four wheels
individually (one after the Test step 15: Reduce pressure, front right
other according to the
test-step sequence). When Test step 16: Maintain pressure, rear left (or rear with Solo ABS)
doing this, carefully follow Test step 17: Reduce pressure, rear left (or rear with Solo ABS)
the instructions in the Tester Test step 18: Maintain pressure, rear right
display. Test step 19: Reduce pressure, rear right
On the Solo ABS, the test of (Test steps 18 and 19 only on vehicles with TC)
the rear-axle valves (test
steps 16...17) can be
performed on the right or Test step Maintain pressure not OK:
left wheel. 1. Hydraulic lines incorrectly allocated if the activated wheel locks up (precondition: inlet valve activated with the F8 key). Incorrect allocation of electrical wires is another possibility if impermissible repairs were made on the wiring harness after accident repairs.
2. Inlet valve faulty.
Test step Reduce pressure not OK:
1. If the activated wheel does not alternately lock up and then rotate freely again but another wheel does this (precondition: the parking brake is not engaged and the selector lever of Tiptronic vehicles is in position N ), the hydraulic lines are swapped.
2. Outlet valve defective.
Troubleshooting:
Perform troubleshooting analogous to test point 10
Test steps 20 - 23
Check speed sensors for Test step No.:
function and incorrect 20 = Front left wheel
allocation. 21 = Front right wheel
To do this, go to the Actual 22 = Rear left wheel
values menu and select the 23 = Rear right wheel
wheel speeds there.
Rotate all four wheels 1. Rotate the wheel on which the test step is not OK.
individually. When each The non-tested wheel must be held when the test is performed on the driven axle.
wheel is rotated, the speed If an indication for a different wheel now appears in the Tester display, the electrical wires are swapped (incorrect allocation of
allocated to the wheel must the speed sensors). This is normally not possible, but could occur if an impermissible repair was performed on the wiring harness after
be displayed. an accident repair.
The non-tested wheel must
be held when the test is
performed on the driven axle. 2. Perform troubleshooting analogous to test points 2 to 9 (depending on the wheel in question)
Test step 24
Check the engine speed in Perform troubleshooting analogous to test point 20 (Engine rpm information missing / DTC 5283).
the Actual values menu.
The current engine speed is
displayed if the engine is
running.