U3005: Retained Accessory Power

What it means

Fault on the retained accessory power (RAP) function that keeps comfort loads (windows, radio) powered for a short time after the key is removed.

At a glance

• Usually lights the warning light of the system that lost communication

How it works

Retained accessory power keeps selected accessories powered briefly after the ignition is switched off. U3005 points to a fault in that function's relay, control logic, or communication, which can leave accessories unavailable or powered for the wrong length of time.

Common causes

Most likely first.

1. RAP relay or BCM logic failed
2. Gateway module routing CAN messages incorrectly
3. CAN terminating resistor (120 Ω) drifted out of spec

Symptoms

• Multiple warning lights may illuminate
• Affected modules may go into limp mode or shut down
• Specific functions inoperative depending on module
• Diagnostic tools may show communication faults

How to diagnose it

1. Scan the body control and related modules for retained accessory power, relay, and communication codes, and review freeze-frame data.
2. Check whether the radio, windows, or other vehicle-equipped retained accessories stay on or shut off as expected after the ignition is removed.
3. Inspect the retained accessory power relay, fuse, and connectors for loose or corroded terminals or heat damage.
4. Check relay power, output, and control signals and the body control module's grounds against the manufacturer's specification.
5. If relay and wiring checks pass, use the manufacturer's procedure to assess body control logic and network or gateway communication.

Common fixes

• Repair a loose or corroded retained accessory power relay connection.
• Replace a failed retained accessory power relay after testing its coil and contacts.
• Repair damaged control or power wiring, or replace a failed fuse after finding the cause.
• Correct a verified body control module configuration or gateway communication fault.

Can I keep driving?

The vehicle is generally drivable if essential systems work, but accessories may not stay powered as intended or may drain the battery if they remain on. Turn off affected accessories and avoid leaving the vehicle unattended with them powered until the fault is resolved.