U0032 DTC: Vehicle Communication Bus A (+) Shorted to Bus (-)

What Does U0032 Mean?

Diagnostic Trouble Code (DTC) U0032 indicates that the Vehicle Communication Bus A CAN High (CAN+) circuit is shorted to the CAN Low (CAN-) circuit. This short circuit prevents normal data transmission between control modules, resulting in communication failures throughout the vehicle network.

Symptoms

• Check Engine Light illuminated
• Multiple warning lights on the dashboard
• ABS, Airbag, or Stability Control warnings
• Loss of communication with one or more control modules
• Power windows, door locks, or HVAC may stop functioning
• Instrument cluster displays communication errors
• Diagnostic scan tool cannot communicate with some modules

Common Causes

• CAN High wire shorted to CAN Low wire
• Damaged or pinched wiring harness
• Melted wire insulation
• Water intrusion inside CAN connectors
• Corroded or loose connector terminals
• Faulty control module internally shorting the CAN network
• Improper aftermarket electrical modifications

Typical Diagnostic Flow

Battery

│

▼

Professional Scan Tool

│

▼

Inspect Bus A CAN Wiring

CAN High (+)
──────────────

✖

CAN Low (-)
──────────────

Short Circuit Between CAN+ and CAN-

▼

Repair Wiring or Replace Faulty Module

How to Diagnose U0032

• Read all stored communication DTCs.
• Inspect the wiring harness for crushed or damaged wires.
• Check connectors for corrosion or moisture.
• Measure CAN bus resistance with the ignition OFF.
• Verify CAN High and CAN Low voltages.
• Disconnect modules individually to isolate the short circuit.

Typical CAN Bus Values

• CAN High: approximately 2.5–3.5 V
• CAN Low: approximately 2.5–1.5 V
• Network resistance: approximately 60 Ω (Ignition OFF)
• Actual specifications may vary by vehicle manufacturer.

Estimated Repair Cost

• CAN wiring repair: $80–300
• Connector replacement: $30–150
• Professional CAN diagnosis: $100–250
• Control module replacement: $250–1,000+

Related DTCs

• U0030
• U0031
• U0033
• U0100
• U0140

Frequently Asked Questions

Can I drive with U0032?

The vehicle may still operate, but important electronic systems may lose communication. Repair should be performed as soon as possible.

What is the most common cause of U0032?

The most common causes are damaged wiring, melted insulation allowing CAN High and CAN Low wires to touch, water intrusion, or a defective control module.

Will clearing the DTC permanently fix U0032?

No. The DTC will return until the short circuit between the CAN communication wires has been repaired.