Open circuit or high resistance in the sensor signal wire; Short to voltage on the sensor signal circuit; Faulty brake booster motor position sensor; Damaged or corroded connector at the sensor or control module; Failed brake booster motor assembly (internal sensor fault); Water intrusion or contamination in the sensor connector; Control module internal fault (less common)

DTC codes / C05xx · Brakes, steering and suspension / C0589

C0589Brake Booster Motor A Position Sensor Circuit High

Q: What does code C0589 mean?

Brake Booster Motor A Position Sensor Circuit High. C0589 indicates that the brake booster motor position sensor circuit is reporting a voltage higher than the manufacturer's expected range, which the control module interprets as a fault. The sensor normally provides a signal proportional to the booster motor's position, and an abnormally high reading suggests an open circuit, short to voltage, or internal sensor failure.

C0589 indicates that the brake booster motor position sensor circuit is reporting a voltage higher than the manufacturer's expected range, which the control module interprets as a fault. The sensor normally provides a signal proportional to the booster motor's position, and an abnormally high reading suggests an open circuit, short to voltage, or internal sensor failure.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaBrakes, steering and suspension

Symptoms you may notice

Illumination of the brake system warning light or traction control light
Often no symptoms besides the warning light
Reduced or inconsistent brake assist, requiring more pedal effort
A stored code in the electronic brake control module with possible related codes
In some cases, the brake booster motor may run continuously or not at all

Common causes, most likely first

Open circuit or high resistance in the sensor signal wire
Short to voltage on the sensor signal circuit
Faulty brake booster motor position sensor
Damaged or corroded connector at the sensor or control module
Failed brake booster motor assembly (internal sensor fault)
Water intrusion or contamination in the sensor connector
Control module internal fault (less common)

How to diagnose and fix it

Verify the code with a scan tool and check for any related codes in the brake control module
Inspect the sensor connector and wiring for corrosion, damage, or loose pins
Measure reference voltage and ground at the sensor connector with a digital multimeter
Check the sensor signal circuit for an open or short to voltage using a wiring diagram
Test the sensor with a multimeter or oscilloscope to confirm it is not internally shorted
Replace the brake booster motor position sensor or the entire booster motor assembly if the sensor is not serviceable separately
Clear codes and perform a road test to verify the repair

What a high sensor reading really means

A high voltage on the signal circuit often indicates an open circuit rather than a failed sensor, so always check wiring continuity before replacing parts.
The sensor may be integrated into the brake booster motor assembly, making replacement more costly and labor-intensive than a standalone sensor.
Intermittent faults can be caused by a chafed wire that only shorts when the engine moves or the vehicle hits a bump, so wiggle-test the harness while monitoring live data.
A weak or failing battery can cause erratic sensor readings on some vehicles, so verify battery and charging system health before condemning the sensor.
This code can be set by a simple loose connector that was not fully seated after previous service, so always check connector engagement first.

Can I keep driving with C0589?

If the brake pedal feels normal, you can drive cautiously to a repair shop, but avoid heavy braking or towing. If brake assist is reduced or the pedal feels hard, stop driving and have the vehicle towed to prevent a potential loss of braking performance.

Tools that help

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