C0598: Brake System Control Module B Performance

What it means

Brake system control module B reports a performance fault — internal self-diagnostic flagged a problem.

At a glance

• Usually lights the ABS or stability-control warning light
• The engine or gearbox may go into limp mode

How it works

Brake system control module B runs internal checks and monitors its operation along with its power, ground, and connected circuits. C0598 sets when module B reports a performance fault, indicating that its self-check or operation did not meet expectations.

Common causes

Most likely first.

1. Internal brake system control module B fault
2. Module power or ground problem
3. Connector or wiring fault

Symptoms

• ABS warning light on
• ESC/stability control deactivated
• Possible reduced brake assist
• Speedometer may behave erratically

How to diagnose it

1. Scan all brake and stability-control modules, record freeze-frame data, and note whether C0598 is current or stored alongside supply or communication codes.
2. Check the battery and module B power and ground connections for looseness, corrosion, or voltage instability.
3. Inspect module B’s connector and harness for water intrusion, damaged terminals, or wiring faults.
4. Use a capable scan tool to review module B status and any available self-test results, following the manufacturer’s diagnostic sequence.
5. If its supplies, grounds, connectors, and circuits pass, use the manufacturer’s tests to confirm whether module B itself has an internal fault.

Common fixes

• Clean and tighten a poor module B power or ground connection.
• Repair damaged wiring or connector terminals serving brake system control module B.
• Carry out the specified module setup or software update if vehicle service information calls for it.
• Replace brake system control module B only after its internal performance fault is confirmed.

Can I keep driving?

ABS or stability control may be unavailable, and brake assist may be affected. Have the brake system checked promptly; do not continue driving if braking feels abnormal or a brake warning indicates a serious fault.