Vehicle Communication Network Circuit Failure
This code indicates a communication problem within the vehicle's network system.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The vehicle's computer is not able to talk to one of its modules properly, which can cause various systems not to work as intended.
What the computer is actually seeing
The ECU detects a loss of communication with one or more control modules over the vehicle network, which can result in issues with the operation of systems like ABS, transmission, or engine control.
What a healthy reading looks like
Typically, the communication voltage levels on the network should be around 2.5V to 5V with a normal resistance of about 60 ohms between the CAN bus terminals.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check the vehicle battery voltage; it should be between 12.0V and 14.5V while running. If low, charge or replace the battery.
- 2Inspect all network wiring and connectors for signs of damage, fraying, or corrosion. Repair any issues found.
- 3Use a scan tool to check for additional codes related to specific modules. Determine which module is unresponsive based on the codes retrieved.
- 4Check the resistance of the CAN bus; it should be around 60 ohms across the two CAN high and CAN low wires. Replace wiring if needed.
- 5If all else seems fine, test the suspected control modules for functionality or replace the worst offender. Conduct a network test after repairs.
Common causes
- Damaged wiring or connectors in the communication network
- Faulty control module that is unresponsive or damaged
- Corrosion or electrical issues at network points or connectors
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive the vehicle with this code?
No, driving with communication faults can cause loss of critical functions like ABS, stability control, or airbag systems.
Will this code return after clearing?
Yes, if the underlying issue isn't resolved, the code is likely to return after a short time.
Why does this code appear along with U0100 or U0121?
These codes indicate communication failures with specific modules and often occur together when there's a network issue.
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