DESCRIPTION
The skid control ECU (brake actuator assembly) is connected to the combination meter assembly via CAN communication.
The slip indicator light blinks during VSC and/or TRC operation.
If a malfunction is detected, the slip indicator light comes on to warn the driver.
When the rear differential cannot be unlocked for 2 consecutive trips, the slip indicator light illuminates.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Note
When replacing the skid control ECU (brake actuator assembly), perform zero point calibration and store system information.
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
As there may be malfunctions in the differential system related to when the system operates with the rear differential locked, check the differential system first.
PROCEDURE
CHECK CAN COMMUNICATION SYSTEM
Check if CAN communication system DTCs are output.
| Result | |||
|---|---|---|---|
|
| DTC is output |
|
CHECK CAN COMMUNICATION SYSTEM Click here |
| DTC is not output |
|
CHECK IF SKID CONTROL ECU CONNECTOR IS SECURELY CONNECTED
Check if the skid control ECU (brake actuator assembly) connector is securely connected.
| OK |
|---|
| The connector is securely connected. |
| Result | |||
|---|---|---|---|
|
| NG |
|
CONNECT CONNECTOR TO ECU CORRECTLY |
| OK |
|
INSPECT BATTERY
Check the battery voltage.
| Standard voltage |
|---|
| 11 to 14 V |
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK OR REPLACE CHARGING SYSTEM OR BATTERY Click here |
| OK |
|
CHECK TERMINAL VOLTAGE (IG1 TERMINAL)
| *a | Front view of wire harness connector (to Skid Control ECU [Brake Actuator Assembly]) |
Disconnect the A4 skid control ECU (brake actuator assembly) connector.
Turn the ignition switch to ON.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT) |
| OK |
|
CHECK HARNESS AND CONNECTOR (GND1 TERMINAL)
Turn the ignition switch off.
| *a | Front view of wire harness connector (to Skid Control ECU [Brake Actuator Assembly]) |
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (GND1 CIRCUIT) |
| OK |
|
READ VALUE USING GTS (SLIP INDICATOR LIGHT)
Reconnect the A4 skid control ECU (brake actuator assembly) connector.
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Chassis / ABS/VSC/TRC / Data List.
According to the display on the GTS, read the Data List.
| Tester Display | Measurement Item | Range | Normal Condition | Diagnostic Note |
|---|---|---|---|---|
| Slip Indicator Light | SLIP indicator light | OFF or ON | OFF: Indicator light off ON: Indicator light on |
- |
| Tester Display |
|---|
| Slip Indicator Light |
Check the GTS display condition of the slip indicator light.
| Result | |||
|---|---|---|---|
|
| Display of the Data List remains OFF |
|
INSPECT METER / GAUGE SYSTEM Click here |
| Display of the Data List remains ON |
|
REPLACE BRAKE ACTUATOR ASSEMBLY Click here |