C05AA: ABS Pump Motor Temperature Too High

What it means

ABS pump motor temperature exceeded safe limit — typically after extended ABS activity or stuck rotor.

At a glance

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

How it works

The ABS control module monitors the pump motor's temperature, directly or through its operating data. This code sets when the motor temperature exceeds its safe limit, which can happen after prolonged ABS operation or if the motor binds and draws excess current.

Common causes

Most likely first.

1. ABS pump motor overheated after extended operation
2. Pump motor binding or drawing excess current
3. Poor motor connection or wiring fault
4. Motor or control module fault

Symptoms

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

How to diagnose it

1. Save freeze-frame data and check pump temperature and activation history in live ABS data, if available, to determine whether overheating followed prolonged operation.
2. Let the pump cool, then inspect its connector and wiring for looseness, corrosion, heat damage, or a poor power connection.
3. Check the pump fuse and measure motor current during a commanded pump test using the manufacturer's procedure.
4. Listen for abnormal pump noise and check for signs of binding or a pump that runs longer than expected.
5. If temperature readings remain implausible or the pump current and wiring are normal, test the temperature monitoring and control module circuits to specification.

Common fixes

• Repair a loose, corroded, or heat-damaged pump connection.
• Repair wiring or power-supply faults that cause excessive resistance or prolonged pump operation.
• Replace a binding or excessive-current pump motor after confirming the fault.
• Replace the control module only if its temperature monitoring or motor control fails testing.

Can I keep driving?

ABS and stability control may be unavailable, and brake assist may be reduced. Avoid hard braking and high-speed driving; if braking is abnormal, stop safely and arrange recovery.