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Code C1104

Symptoms

• Warning lights on the dashboard

• Intermittent loss of communication between control modules

• Erratic vehicle behavior

Common Causes

• Damaged or corroded wiring in the FlexRay circuit

• Faulty FlexRay control module

• Poor connections at the FlexRay connectors

Glossary

FlexRay: A high-speed communication protocol used in automotive networks.

Short Circuit: An electrical fault where current travels along an unintended path.

Related Codes

• C1105

• C1106

Laymans terms

This code means that there's a problem with the car's communication system, like when your phone can't connect to Wi-Fi because the wires are mixed up.

Explanation

The FlexRay circuit is responsible for high-speed communication between various electronic components in the vehicle. A short circuit means that the electrical signals are not traveling correctly due to a wiring issue.

Technical description

The C1104 code indicates a short circuit condition in the FlexRay communication network. This network is used for data exchange between multiple control units in the vehicle. A short in the FlexRay_High or FlexRay_Low circuit can disrupt communication, leading to various system malfunctions.

Diagnosis steps

• Inspect the FlexRay wiring for damage or corrosion

• Check the connections at the FlexRay connectors

• Use a diagnostic tool to test the FlexRay control module

Repair procedures

• Repair or replace damaged wiring

• Clean and secure all FlexRay connectors

• Replace the FlexRay control module if faulty

Tools required

• OBD-II scanner

• Multimeter

• Wiring repair kit

Estimated repair cost

$200 - $600

Difficulty level

Moderate

Commonly affected vehicles

• BMW 3 Series

• Audi A4

• Mercedes-Benz C-Class

Preventive measures

• Regular inspection of vehicle wiring

• Avoiding exposure of vehicle electronics to moisture

• Routine maintenance checks

Error code type

Communication Network Issue

User experience recommendations

• Avoid driving the vehicle until the issue is diagnosed and repaired

• Consult a professional mechanic for accurate diagnosis

Warranty information

Check with the vehicle manufacturer for warranty coverage on electronic components.

Historical data

The C1104 code has become more common with the increased use of high-speed communication networks in modern vehicles.

Urgency level

High – A short in the communication network can lead to serious vehicle malfunctions.

Legal and safety notice

Driving with a faulty communication system can be dangerous and is not recommended.

Testing conditions

• Vehicle at operating temperature

• All electronic systems powered on

Component location

The FlexRay network components are typically located throughout the vehicle, connecting various control modules.

FAQs

Q: Can I drive with a C1104 code?
A: It's not recommended as it can lead to unpredictable vehicle behavior.

Q: How do I know if my FlexRay circuit is shorted?
A: A diagnostic scan tool can help identify a short circuit in the FlexRay network.

Last updated: Jun 8, 2026 • Source: internal database
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