DTC U0014 – Medium Speed CAN Communication Bus Low

on

DTC U0014 – Medium Speed CAN Communication Bus Low

What Does DTC U0014 Mean?

DTC U0014 indicates that the vehicle has detected an abnormal voltage condition on the Medium-Speed Controller Area Network (MS-CAN) Low communication circuit. This usually indicates a wiring fault, poor connection, or a control module disrupting communication. The exact definition may vary by manufacturer.

Severity

High. A CAN communication fault can interrupt data exchange between multiple control modules and affect vehicle operation.

Can You Drive with U0014?

Yes, the vehicle is generally drivable, but some electronic systems may stop working correctly. The fault should be repaired as soon as possible.

Symptoms

  • Check Engine or communication warning light.
  • Multiple U-codes stored.
  • Loss of communication with one or more control modules.
  • Instrument cluster warning messages.
  • Intermittent operation of electrical accessories.

Common Causes

  • CAN Low wire shorted to ground.
  • Open or damaged CAN Low wiring.
  • Loose or corroded connectors.
  • Faulty control module affecting the network.
  • Low battery voltage or charging system faults.

How to Diagnose U0014

  1. Scan all control modules for communication DTCs.
  2. Check battery voltage and charging system.
  3. Inspect CAN High and CAN Low wiring.
  4. Inspect connectors for corrosion or loose terminals.
  5. Measure CAN bus voltage and resistance according to the factory service manual.
  6. Disconnect suspected modules one at a time if necessary.
  7. Repair the fault, clear the codes, and verify normal communication.

Typical CAN Network Layout

         PCM
          │
          ▼
      CAN Bus
          │
          ▼
         BCM
          │
          ▼
         ABS
          │
          ▼
         TCM
          │
          ▼
 Instrument Cluster

Estimated Repair Cost

  • Battery or charging repair: $50–250
  • CAN wiring repair: $80–300
  • Connector replacement: $30–150
  • Control module replacement: $300–1,000

Related DTCs

  • U0011
  • U0012
  • U0013
  • U0015

Frequently Asked Questions

Can a short to ground cause U0014?

Yes. A short to ground on the CAN Low circuit is one of the most common causes of U0014.

Can a faulty control module trigger U0014?

Yes. A failed module can overload or disrupt the CAN network and generate communication codes.

Is U0014 the same on every vehicle?

No. The exact code definition and diagnostic procedures vary by manufacturer. Always consult the factory service information for the specific vehicle.

Comments

Post a Comment