Signal Specification ABS
All the values given below are between the terminal stated in column 1 and terminal 16 (ground). This applies unless otherwise indicated in brackets. ABS control module terminals 1-40 correspond to terminals 1-40 on the breakout box.
CAUTION:
Before taking readings: Connect the breakout box. Check the ground terminals.
| U | DC voltage in volts (V) | % duty | Duty cycle (pulse ratio) as a percentage (%) |
| Ubat | battery voltage in volts (V) | f | frequency in Hertz (Hz) |
| Ulow | voltage approximately 0 V | UAC | AC voltage in volts (V) |
| Terminal | Signal type | Ignition on. Engine idling | Other | Reading off parameters |
|---|---|---|---|---|
| 1 | Signal ground, right rear wheel sensor | U ≈ Ulow | - | - |
| 3 | Signal (+), right rear wheel sensor | U ≈ 0.2 V UAC ≈ Ulow |
AC voltage is generated when the wheel is rotated. The voltage (UAC ) increases with wheel speed. | - |
| 4 | Signal ground, right front wheel sensor | U ≈ Ulow | - | - |
| 5 | Signal (+), right front wheel sensor | U ≈ 0.2 V UAC ≈ Ulow |
AC voltage is generated when the wheel is rotated. The voltage (UAC ) increases with wheel speed. | - |
| 6 | Signal ground, left front wheel sensor | U ≈ Ulow | - | - |
| 7 | Signal (+), left front wheel sensor | U ≈ 0.2 V UAC ≈ Ulow |
AC voltage is generated when the wheel is rotated. The voltage (UAC ) increases with wheel speed. | - |
| 8 | Signal ground, left rear wheel sensor | U ≈ Ulow | - | - |
| 9 | Signal (+), left rear wheel sensor | U ≈ 0.2 V UAC ≈ Ulow |
AC voltage is generated when the wheel is rotated. The voltage (U AC ) increases with wheel speed. | - |
| 11 | Diagnostic lead | 1-4 V below Ubat Other values apply if the fault-tracing instrument is connected to the data link connector (DLC) |
- | - |
| 13 | Control signal, ABS warning lamp | Lamp lit: U above approximately 3 V Lamp not lit: U ≈ Ulow |
The warning lamp goes out when the control module grounds the signal. The warning lamp lights when the control module increase the voltage to above approximately 3 V. | - |
| 14 | Signal, stop (brake) light switch | Open: U ≈ Ulow Closed: 0-1.5 V below Ubat |
The stop (brake) light switch closes when braking and the control module is supplied with voltage | 5 |
| 15 | 15 supply (power supply from the ignition switch) |
U bat | - | - |
| 16 | Ground (measured to the battery negative terminal) |
Ulow | - | - |
| 17 | 30- supply, pump motor via the motor relay) |
Ubat | - | - |
| 18 | 30 supply, valves (via the valve relay) |
Ubat | - | - |
| 21 | Control signal, EBD warning lamp | Lamp lit: U ≈ Ulow Lamp not lit: U ≈ 6.9 Volt |
The lamp lights if the brake fluid level falls to a certain level. | - |
| 23 | Signal, left rear wheel speed (to the DSA control module) |
U ≈ 0 V-Ubat
(depending on the position of the wheel) The frequency (f) increase with the speed of the wheel. |
Pulsed signal between approximately 0 V-Ubat with a fixed pulse ratio (duty cycle ≈ 50%) | - |
| 24 | Signal, right rear wheel speed (to the DSA control module) |
U ≈ 0 V-Ubat
(depending on the position of the wheel) The frequency (f) increase with the speed of the wheel. |
Pulsed signal between approximately 0 V-Ubat with a fixed pulse ratio (duty cycle ≈ 50%) | - |
| 25 | Signal, left front wheel speed (to the DSA control module) |
U ≈ 0 V-Ubat
(depending on the position of the wheel) The frequency (f) increase with the speed of the wheel. |
Pulsed signal between approximately 0 V-Ubat with a fixed pulse ratio (duty cycle ≈ 50%) | - |
| 26 | Signal, right front wheel speed (to the DSA control module) |
U ≈ 0 V-Ubat
(depending on the position of the wheel) The frequency (f) increase with the speed of the wheel. |
Pulsed signal between approximately 0 V-Ubat with a fixed pulse ratio (duty cycle ≈ 50%) | - |