HOWO Mining Truck ABS Warning Light Troubleshooting Guide
The ABS warning light on HOWO mining trucks often lights up due to harsh working conditions in mines such as mud, dust and heavy vibration. Common causes include contaminated sensors, damaged wiring, poor contact, brake system faults or occasional system errors. When the ABS light is on, the normal braking function still works, but the anti-lock function fails. When driving downhill with heavy loads or on slippery ground, wheels may lock up, skid or drift. Troubleshooting and repair must be carried out promptly. Below is the complete operation procedure from simple on-site inspection to professional maintenance.
1. Quick On-site Self-check (No tools required, 5-minute inspection)
Check for minor intermittent faults first; most simple false alarms can be eliminated directly.
1.1 System reset to clear occasional false alarms
Vibration on mining sites may cause temporary signal disorder of the ABS system and trigger false faults.Operation: Shut down the engine, turn off the main power switch of the whole vehicle. Wait for 3–5 minutes, then switch the power back on. Start the truck and observe the ABS light.
If the light goes out: it was an intermittent system fault, the truck can operate normally.
If the light stays on after restart: proceed to the next inspection.
1.2 Check brake fluid level and condition
Check the reservoir of the main brake cylinder when the engine is cold. The liquid level must stay between the MIN and MAX marks. Low liquid level may trigger ABS protection alarm. Top up with the specified brake fluid to the standard level.Meanwhile check whether the brake fluid is turbid, waterlogged or deteriorated. The humid mine environment easily causes brake fluid to absorb water and lose performance. Replace deteriorated brake fluid and bleed air from pipelines.
1.3 Inspect battery and connections
The ABS control system requires stable voltage. Low battery charge, loose connections or oxidized terminals will cause abnormal power supply to the ABS module and turn on the warning light.Check whether the battery positive/negative terminals and ground wires are tightly fastened without looseness or rust. Clean oxide on terminals and retighten them. Measure battery voltage: if the idling voltage is lower than 24V or the voltage drops sharply during startup, recharge or replace the battery.
2. Troubleshooting of High-incidence Core Faults
If simple checks fail, about 90% of faults come from wheel speed sensors, wiring and signal tone rings — the most frequent faults for HOWO mining trucks.
2.1 Inspection and cleaning of wheel speed sensors (top cause)
Mud, iron powder and dust easily cover the ABS wheel speed sensors and tone rings on wheel hubs, leading to distorted or lost signals and activating the alarm.
Repair steps:
Stop the truck, turn off engine and engage parking brake. Clean mud, iron chips and oil from the inner side of wheel hubs, sensor probes and tone rings. Do not scrape hard with sharp tools to avoid damaging probes and tone rings.
Check that the sensor has no cracks or damage and is firmly mounted. The standard gap between probe and tone ring is 0.5–1 mm. Adjust mounting bolts slightly if offset.
After cleaning, test drive at low speed for 3–5 km for signal calibration. If the warning light turns off, the fault is fixed.
If the light remains on, measure sensor resistance with a multimeter. Normal resistance: 800–1200 Ω. Infinite resistance, extremely low reading or unstable readings indicate sensor damage; replace with an original sensor.
2.2 Damaged wiring and poor contact inspection
Heavy vibration, scratch from broken stones and immersion in mud/water often wear the outer insulation of ABS sensor cables, break internal wires or make connectors oxidized with water ingress.
Inspection: Check ABS wiring for each wheel, especially cables at swinging wheel positions and chassis routing. Look for cracked insulation, broken wires, loose connectors and mildew from water. Test continuity section by section to locate open circuits between ABS controller and wheel sensors.
Repair: Wrap slightly damaged cables with insulation material. If core wires break or connectors are corroded, reconnect or replace connectors. After repair, apply waterproof and anti-abrasion fixing to prevent repeated faults, then clear fault codes and test drive.
2.3 Inspection of signal tone rings
Check ABS tone rings at wheel bearings. Look for broken teeth, deformation, heavy rust or trapped debris. Damaged, deformed or unevenly worn tone rings lead to abnormal wheel speed signals and ABS alarms. Light rust can be cleaned; replace tone rings if teeth are broken or severely deformed.
3. Professional Maintenance with Diagnostic Equipment
If above inspections show no abnormality, use Sinotruk dedicated diagnostic scanner to read ABS fault codes for precise positioning, avoiding blind repairs.
C0035–C0038 (four-wheel sensor faults): Corresponding wheel sensor failure, open/short circuit of wiring. Replace sensor or repair wiring.
Voltage-related fault codes: Check power supply, fuses and relays of ABS module. Replace blown fuses with same-specification parts and check for hidden short circuits.
Pump / module fault codes: Internal failure of ABS pump or control unit. This is hardware damage and needs professional repair or assembly replacement.
After maintenance, clear fault codes via diagnostic tool. Carry out test drive with no load and full load respectively. If no warning light appears at low and medium speeds and emergency braking has no wheel lock or deviation, the repair is complete.
4. Mine Operation Precautions & Preventive Measures
Clean mud and dust on ABS sensors around wheel hubs after daily work to prevent iron powder from sticking to probes and interfering with signals.
Regularly check retaining clips for ABS wiring to avoid cable abrasion caused by vibration. Apply waterproof protection to connectors.
Do not operate the truck at high speed or heavy load downhill when the ABS light is still on, to reduce risk of brake failure.
Use original spare parts for repairs. Aftermarket sensors usually have low precision and may trigger repeated alarms.