U0074Network Communication

Control Module Communication Bus B Off

U0074 means a control module detected too many errors on communication bus B and shut off its transmitter (bus-off). It usually points to a wiring short, a failing module, or bus termination problems.

🚗 Not recommended. A bus-off condition on bus B means affected modules have stopped communicating.

HIGH

severity

🎯 Top Causes, Ranked by Likelihood

#1Bus B wiring short or open$50-$500

45%

A short or open on bus B generates enough errors to force bus-off.

#2Failed module on bus B$300-$1200

30%

One faulty module can flood the bus with errors.

#3Termination or connector fault$50-$300

15%

Bad termination or connectors disrupt the bus.

🩺 Common Symptoms

Modules on bus B offline
Warning lights
No communication with some modules
Erratic behavior
Other U-codes stored

💰 Repair Cost: DIY vs Shop

DIY Cost

$50-$400

Shop Cost

$150-$1000

📋 Free OBD2 Code Cheat Sheet

The 50 most common codes with likely cause and DIY fix cost. Sent once, no spam.

🔧 How to Diagnose U0074

1Identify which modules are on bus B

2Measure bus resistance and check for shorts or opens

3Disconnect bus B modules one at a time to isolate a faulty unit

4Repair the fault and clear the bus-off condition

❓ Frequently Asked Questions

Can I drive with U0074?

Not safely. Modules on bus B have stopped communicating. Diagnose it first.

How is bus B different from bus A?

Vehicles often have several CAN buses. Bus A and bus B are separate networks connecting different groups of modules.

What causes U0074?

Usually a wiring short or open on bus B, or a single failing module flooding that network.

🔗 Related Codes

U0073U0001U0100U0140