B2404 Code - Audio Steering Wheel Switch Circuit Fault
Quick Answer
Two different steering wheel switch configurations are available, depending on whether the vehicle is equipped with the SYNC system. Common causes include Faulty Audio Steering Wheel Switch, Audio Steering Wheel Switch harness is open or shorted, Audio Steering Wheel Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- B2404 indicates Audio Steering Wheel Switch Circuit Fault.
- Common causes
- Common causes include Faulty Audio Steering Wheel Switch, Audio Steering Wheel Switch harness is open or shorted, Audio Steering Wheel Switch circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code B2404 Description
On vehicles without the SYNC system, all of the steering wheel control switches are wired to the Audio Control Module (ACM). The steering wheel controls are: VOL+, VOL-, SEEK+, SEEK-, and MEDIA. The SEEK+ and SEEK- switches are represented by arrows.
For vehicles equipped with the SYNC system, the steering wheel controls are: VOL+, VOL-, SEEK+, SEEK-, MEDIA, VOICE, PHONE, and OK. The SEEK+ and SEEK- switches are represented by arrows, the VOICE button is represented by an icon of someone speaking, and the PHONE button is represented by an icon of a phone with an up-and-down arrow. The VOICE, PHONE, and OK switches are wired to the accessory protocol interface module (APIM), while the remaining switches are wired to the ACM.
For all switches, a reference voltage is sent from the appropriate module to the steering wheel controls. When a switch is pressed, the voltage is routed through a specific resistor value for each function. The module provides the ground for the reference voltage. The module uses this reference voltage to determine which control input function has been selected.
What are the Possible Causes of the DTC B2404?
- Faulty Audio Steering Wheel Switch
- Audio Steering Wheel Switch harness is open or shorted
- Audio Steering Wheel Switch circuit poor electrical connection
How to Fix the DTC B2404?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B2404 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Makes
- B2404 Ford — Audio Steering Wheel Switch Circuit Fault
- B2404 Lincoln — Audio Steering Wheel Switch Circuit Fault
- B2404 Mercury — Audio Steering Wheel Switch Circuit Fault
Frequently Asked Questions about B2404 Code
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