Wheel Speed Sensor Diagnosis
Compare all four wheel speeds and scope the suspect sensor while reproducing the conditions.
Loading…
What you will learn
- Interpret wheel speed live data
- Scope a wheel speed sensor
- Localise mechanical vs electrical faults
Advertisement
The ABS module compares wheel speeds continuously. A single sensor that drops out while others are stable points directly at that wheel. Live data is the fastest first test; a scope recording while driving over bumps confirms intermittent faults.
Remember the mechanical side. Air gap, a damaged reluctor ring or debris after bearing work create electrical-looking faults. Static resistance tests can pass while the signal still drops out dynamically.
Loading…
Loading…
CASE 009
ABS Warning and Intermittent Pulses
Open case →
The ABS light comes on intermittently at low speed and the pedal pulses occasionally when braking gently.
Loading…
Loading…
Key points
- All four speeds must match when driving straight
- Intermittent dropouts need dynamic evidence
- Recent bearing work is a clue
All values shown are training examples. Real thresholds depend on the manufacturer, engine, temperature and system — always confirm with the vehicle service documentation.
Advertisement