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U3005 — Retained Accessory Power

Manufacturer-specificNetwork / communication

Code U3005 indicates a malfunction in the Retained Accessory Power (RAP) system. This system allows specific electrical accessories, such as the radio and power windows, to remain operational after the ignition is turned off until a door is opened.

Symptoms

What causes it — most likely first

1. Faulty Door Switch

A failed or stuck door ajar switch prevents the system from detecting when a door is opened to kill accessory power.

2. Wiring Harness Damage

Frayed, shorted, or corroded wiring in the RAP circuit can disrupt the signal between the switch and the control module.

3. Failed RAP Relay

A stuck or burnt-out relay may either permanently provide power or fail to provide power to the accessories.

4. Corroded Ground Connections

Poor grounding in the electrical system can cause erratic behavior or a complete failure of the RAP circuit.

5. Body Control Module (BCM) Failure

The BCM typically manages the RAP logic; internal circuitry failure can cause the system to malfunction.

6. PCM/ECM Fault

While rare, a failure in the engine computer's communication with the BCM could trigger this code.

How it's diagnosed

  1. Verify if accessories shut off correctly when each door is opened
  2. Inspect all door ajar switches for mechanical failure or electrical continuity
  3. Check all relevant fuses and relays associated with accessory power
  4. Perform a visual inspection of the wiring harness for chafing or corrosion
  5. Test ground points for low resistance to the chassis
  6. Scan the Body Control Module for complementary fault codes

Code facts & related codes

SystemNetwork / communication
StandardizationManufacturer-specific (P1/B1/C1/U1)

Frequently asked

Is it common to replace the PCM for a U3005 code?

No. The RAP system is primarily managed by the BCM and door switches. Replacing the PCM is rarely the correct fix and is usually unnecessary.

Will this code prevent my car from starting?

No, this is a convenience system fault and does not typically affect the engine's ability to start or run.

Can a dead battery cause this code?

Low system voltage can sometimes trigger communication codes, but U3005 is more likely a circuit or switch failure.