Retained Accessory Power

What does U3005 mean?

U3005 stands for Retained Accessory Power. Two or more of the car's computer modules are not communicating properly over the vehicle network (CAN bus).

Network codes cover the communication between the car's computer modules. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.

Common causes

• Low or weak battery
• Damaged network wiring or connector
• A module that has lost power or failed
• Aftermarket accessories interfering with the network

What to do

1. Read all stored and pending codes with a scanner. Several codes together often point to one cause.
2. Note the freeze frame data (speed, temperature, load) recorded when the code was set.
3. Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
4. Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.

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Frequently asked questions

What does U3005 mean?

U3005 means “Retained Accessory Power”. It belongs to the network communication group: Two or more of the car's computer modules are not communicating properly over the vehicle network (CAN bus).

Is it safe to drive with U3005?

You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.

How do I clear U3005?

Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.

Related codes

• U3001Control Module Improper Shutdown
• U3002Vehicle Identification Number
• U3003Battery Voltage
• U3004Accessory Power Relay
• U3006Control Module Input Power "A"
• U3007Control Module Input Power "B"
• U3008Control Module Ground "A"
• U3009Control Module Ground "B"

Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.