U2109 — CAN D circuit open

Network (CAN bus, communication)

This is a generic or manufacturer-specific U-code, often indicating a 'Control Module Switched OFF' or 'Lost Communication with J010 (data bus on-board diagnostic interface)'. In some contexts, it can mean a control module has shut down or is intermittently losing power.

To monitor the power status and communication readiness of a control module within the vehicle network.

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Can I drive with U2109?

You can usually drive home and book an inspection within a few days.

Likely root causes

• Intermittent power or ground supply issue to a specific control module
• Internal fault within the affected control module (e.g., data bus interface circuitry)
• Loose or corroded connector at the control module or within its power/ground circuit

Frequently asked questions

What does fault code U2109 mean?

U2109 means CAN D circuit open.

Can I keep driving with U2109?

You can usually drive home and book an inspection within a few days.

Related fault codes

• U2100 — CAN C bus off
• U2101 — CAN C performance
• U2102 — CAN C circuit short to battery
• U2103 — CAN C circuit short to ground
• U2104 — CAN C circuit open
• U2105 — CAN D bus off
• U2106 — CAN D performance
• U2107 — CAN D circuit short to battery
• U2108 — CAN D circuit short to ground

Get a full diagnosis for U2109 with AutoUncover.