Test Step 12.4

Test 12.4:

Sensor defect (front left), faults at front left speed sensor, pulse wheel or wires:

Other indicators:

- Static defect with and without control:
- After engine restart and driving oft, "ASC defect" appears in the instrument cluster display at a speed of 12 km/h.
- In the case of static defect during a trip at a speed below 44 km/h, "ASC defect' appears in the instrument cluster display after 20 sec (not if speed drops below 12 km/h during the 20 sec), or after stopping vehicle and driving off once again, "ASC defect appears in the instrument cluster display at a speed of 24 km/h.
- ABS lamp ON until ignition is switched oft, ABS lamp oft when engine restarted.

Test:

- Measure resistance between Pin 8 and 26, 650 Ohm ... 1.6 KOhm
- Detach speed sensor connection in front left engine compartment. Measure Pin 8 and 26 for a short to ground (-) and positive (+), move wires it necessary. Renew front left speed sensor. Visual inspection of pulse wheel.

Other indicators:

- Intermittently occurring defect with and without control:
- Defect occurs at a speed above 44 km/h, "ASC defect" appears immediately in the instrument cluster display, further control possible on the vehicle side not effected (e.g. loose contact at sensor/wire).
- ABS lamp ON until ignition is switched oft. ABS lamp oft when engine restarted.


Test:

- Detach speed sensor connection in front left engine compartment. Bypass wire harness side of connector.Measure resistance Pin 8 and 26, 0 ... 1.5 Ohm (move wires). Check wires for a short to ground (-) and positive (+). Renew front left speed sensor. Visual inspection of pulse wheel, renew pulse wheel if teeth damaged.