01 Locked out of your car? Here's what to do next! • 02 Drivers Left Speechless After Seeing What That Mysterious B… • 03 How to Fix a Car That Loses Power in 2nd Gear: A Comprehens… • 04 P0013 B Camshaft Position - Actuator Circuit (Bank 1) • 05 Lean vs. Rich: Which Engine Problem Should You Worry About … • 06 C0035 - Left Front Wheel Speed Circuit Malfunction • 07 The Benefits of Catalytic Converters in Vehicle Exhaust Sys… • 08 How Does Nitrous, Superchargers, and Turbochargers Boost Yo… • 09 Why Your Garage Has Customers But No Profit • 10 Exploring the Toyota 1NZ Engine: Features and Performance A… •

DTC codes / C06xx · Brakes, steering and suspension / C0654

C0654Left Front Wheel Speed Sensor B Circuit High

This code means the antilock braking system (ABS) module has detected an abnormally high voltage on the signal circuit for the left front wheel speed sensor, which is the sensor that reports how fast that wheel is turning. The module compares the voltage it receives against the expected range and sets the code when the signal stays above the high threshold for a set period, so the ABS and often traction control are disabled until the fault is repaired.

SystemChassis
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaBrakes, steering and suspension

Symptoms you may notice

  • ABS warning light illuminated on the dashboard, often accompanied by the traction control and stability control lights
  • Traction control and stability control systems disabled, which may be announced by a message on the driver information display
  • ABS may not activate during hard braking, increasing stopping distance on slippery surfaces
  • Speedometer or cruise control may behave erratically if the module uses this wheel signal for vehicle speed
  • Often no symptoms besides the warning light, with normal brake pedal feel and normal base braking performance

Common causes, most likely first

  1. Damaged or chafed sensor signal wire shorted to a power source or to the sensor supply voltage, often inside the front wheel well or near the strut
  2. Corroded, loose, or water-intruded electrical connector at the left front wheel speed sensor or at the ABS module
  3. Failed left front wheel speed sensor that is internally shorted and pulling the signal circuit high
  4. Metal debris, a damaged tone ring, or excessive wheel bearing play causing an erratic signal that the module interprets as a high-voltage condition
  5. Faulty ABS control module with an internal circuit fault on the left front sensor input
  6. Aftermarket or incorrectly routed wiring repairs that introduce a short to voltage on the signal circuit

How to diagnose and fix it

  1. Inspect the left front wheel speed sensor connector and the harness routing for corrosion, chafing, or contact with moving suspension parts, and repair any damaged wiring
  2. Disconnect the sensor and measure the signal circuit voltage with the key on to see whether the high voltage is coming from the sensor side or the module side
  3. Check the sensor signal with an oscilloscope or a scan tool live data stream while spinning the wheel by hand to confirm whether the sensor output is stuck high or erratic
  4. Measure the sensor resistance and compare it with the manufacturer's specification, and inspect the tone ring for debris or damage
  5. Perform a voltage drop test on the sensor ground and supply circuits to rule out a poor connection that skews the signal
  6. If the wiring and sensor test good, substitute a known-good sensor or module input to isolate whether the ABS module is the source of the high voltage
  7. Clear the codes and verify the repair with a road test that activates ABS and traction control, confirming the light stays off and live data matches wheel speed

Why this code often is not the sensor

  • A short to voltage on the signal wire from a chafed harness near the strut or wheel well is a more common cause of a high-voltage code than a failed sensor, so inspect the loom before condemning the sensor.
  • Water intrusion into the connector can create a conductive path that pulls the signal circuit high, and the sensor itself may test perfectly once the connector is dried out.
  • A worn wheel bearing or a damaged tone ring can produce a signal the module reads as out of range, so always check bearing play and tone ring condition before replacing electrical parts.
  • This code does not always mean the ABS module is faulty, but a module with an internal short on one input channel can set the same code even with a new sensor and perfect wiring.
  • Aftermarket sensors with incorrect internal resistance can set a high-voltage code on some vehicles, so compare the replacement part against the original specification.

Can I keep driving with C0654?

The vehicle remains safe to drive with normal base braking, but ABS and traction control are disabled, so avoid slippery roads, hard braking, and towing until the fault is repaired. Have the system diagnosed promptly because the loss of ABS increases stopping distance in an emergency.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage