U0097: Vehicle Communication Bus H (-) Open

What it means

A fault is detected on the negative conductor of vehicle communication bus H; the code descriptor specifies an open circuit. Which functions are affected depends on the vehicle’s network design.

How it works

Bus H carries data between the modules connected to that network over positive and negative conductors. U0097 is set when the negative conductor is detected as open, interrupting the communication path for modules that depend on bus H.

Common causes

Most likely first.

1. Open or damaged bus H negative wire
2. Loose or corroded connector
3. A module, gateway, or bus termination fault

Symptoms

• Communication faults in modules using bus H
• Warning lights or messages
• Functions relying on bus H may be unavailable

How to diagnose it

1. Scan all accessible modules for U0097 and related communication codes, and record which modules cannot be reached and any available event data.
2. Use the vehicle wiring information to locate the bus H negative conductor, its connectors, and any specified termination points.
3. Inspect that conductor and its connectors for a break, pulled-out or corroded pins, and damage from rubbing, heat, or previous repairs.
4. Check continuity of the bus H negative wire and connector path with power isolated as directed by the manufacturer.
5. If the wire path is intact, follow the manufacturer's procedure to check bus termination and isolate a module or gateway that may be opening the circuit.

Common fixes

• Secure or clean a loose or corroded bus H negative connector.
• Repair a broken or damaged section of the negative conductor.
• Restore a failed bus termination or repair a gateway or module found to be interrupting the line.

Can I keep driving?

Avoid unnecessary driving if bus H serves systems needed for safe operation, or if warning messages accompany loss of those functions. If the vehicle behaves abnormally, stop in a safe place and arrange diagnosis before continuing.