U0194 is a generic OBD-II network communication fault code that means Lost Communication With Digital Audio Control Module B. The vehicle has detected that expected communication with Digital Audio Control Module B (DACM-B) has been lost.
Digital Audio Control Module B is an electronic module associated with the vehicle's digital audio or infotainment architecture on applicable vehicles. Its exact functions, location, power supply, communication network, and relationship with the radio, display, amplifier, Bluetooth, or other multimedia components vary by manufacturer and model.
U0194 does not automatically mean that Digital Audio Control Module B has failed. A blown fuse, missing power, poor ground, damaged wiring, connector corrosion, low system voltage, network problems, software/configuration issues, or another module affecting the communication network can also cause this code.
Fault Code Description
U0194 = Lost Communication With Digital Audio Control Module B.
Module abbreviation: DACM-B — Digital Audio Control Module B.
Code type: Generic OBD-II Network Communication Code.
Likely fault location: Digital Audio Control Module B, fuse, power supply, ground circuit, communication wiring, connectors, gateway, or vehicle communication network.
The letter B identifies a particular Digital Audio Control Module within the vehicle's electronic architecture. It does not necessarily mean that every vehicle contains separate physical modules A and B.
What Does U0194 Mean?
Modern vehicles use communication networks to allow electronic control modules to exchange information. Digital Audio Control Module B communicates with other modules through the vehicle's applicable communication network.
When another control module expects messages from DACM-B but those messages are no longer received, the vehicle can store U0194.
The communication failure may be caused by loss of module power, a poor ground, an open or shorted communication circuit, damaged connectors, network faults, low voltage, software problems, or an internal module failure.
The exact network technology is vehicle-specific. Some vehicles may use CAN communication, while other systems may use different network architectures or gateways.
Symptoms of U0194
- Loss of digital audio functions.
- No audio output on applicable systems.
- Radio or infotainment functions may not operate correctly.
- Audio source may disappear from the infotainment menu.
- Bluetooth or other multimedia functions may become unavailable.
- Navigation or display-related functions may be affected on applicable vehicles.
- Infotainment system may freeze, reset, or operate intermittently.
- Communication or audio-related warning messages may appear.
- Diagnostic scan tool may be unable to communicate with DACM-B.
- Additional U-codes may be stored in other control modules.
The actual symptoms depend on the functions assigned to Digital Audio Control Module B in the specific vehicle.
Common Causes of U0194
- Blown fuse supplying Digital Audio Control Module B.
- Loss of battery power.
- Loss of ignition or accessory power.
- Poor module ground.
- Open communication circuit.
- Short circuit to power.
- Short circuit to ground.
- High resistance in the communication wiring.
- Damaged wiring harness.
- Corroded electrical connector.
- Loose or damaged connector terminals.
- Water or moisture intrusion.
- Low or unstable vehicle voltage.
- Fault in another control module or network gateway.
- Software or configuration problem on applicable vehicles.
- Internal failure of Digital Audio Control Module B.
Digital Audio Control Module B vs. Radio
Digital Audio Control Module B and the vehicle's physical radio or infotainment head unit are not necessarily the same component.
Digital Audio Control Module B
DACM-B is the electronic module identified by the vehicle diagnostic system as Digital Audio Control Module B.
Depending on the vehicle, it may perform digital audio control or other multimedia-related functions and communicate with other infotainment modules.
Radio / Infotainment Module
The radio or infotainment unit is the user-facing component. DACM-B may be integrated into the same assembly or installed as a separate electronic module.
Therefore, U0194 should not automatically be diagnosed as a failed radio. The actual system architecture must be identified from the vehicle-specific wiring diagram and service information.
U0194 Digital Audio Module B Fuse
Digital Audio Control Module B requires one or more electrical power supplies protected by fuses. Depending on the vehicle, the applicable fuse may be located in the interior fuse box, instrument-panel fuse box, or engine-compartment fuse box.
The fuse may be labeled AUDIO, RADIO, MEDIA, INFOTAINMENT, or another manufacturer-specific designation.
There is no universal fuse number for U0194. Always use the fuse diagram for the exact vehicle.
How to Check the Fuse
- Locate the vehicle-specific fuse diagram.
- Identify the fuse supplying DACM-B.
- Verify the correct fuse rating.
- Inspect the fuse for an open element.
- Test for voltage at the fuse when the circuit is energized.
- Inspect fuse terminals for corrosion or overheating.
- Never install a higher-rated fuse.
If a replacement fuse blows immediately, do not repeatedly replace it. Diagnose the circuit for a short circuit, damaged wiring, water intrusion, or excessive current draw.
U0194 Module Power and Ground
A communication fault does not necessarily mean that the communication circuit itself is defective. A module that has lost its power or ground may simply stop communicating with the vehicle network.
Use the vehicle-specific wiring diagram to identify all battery, ignition, accessory, wake-up, and ground circuits connected to DACM-B.
Verify the required voltage and ground quality according to the manufacturer's specifications.
U0194 Wiring and Communication Circuit
Inspect the wiring between Digital Audio Control Module B and the applicable vehicle communication network.
- Check for open circuits.
- Check for short circuits to power.
- Check for short circuits to ground.
- Check for excessive resistance.
- Inspect damaged insulation.
- Inspect connector terminals.
- Look for corrosion or water contamination.
- Inspect wiring affected by vibration or previous repairs.
Do not apply one universal voltage or resistance specification to every vehicle. Communication wiring and network architecture vary by manufacturer.
How to Diagnose U0194
1. Perform a Complete Vehicle Scan
Scan all available control modules with a professional scan tool. Record U0194 and any additional communication, voltage, audio, or network-related codes.
If several modules report communication faults, investigate common power supplies, grounds, gateways, or network problems before replacing DACM-B.
2. Attempt Communication With DACM-B
Use the scan tool to determine whether Digital Audio Control Module B can be accessed.
If the scan tool cannot communicate with DACM-B, continue with power, ground, connector, and communication-circuit testing.
If DACM-B communicates normally but U0194 is stored, the fault may be intermittent, historical, or caused by another module or network condition.
3. Check the Fuse Box
Inspect all fuses associated with the audio, digital audio, radio, and infotainment systems. Verify both fuse condition and electrical supply.
4. Test Module Power and Ground
Verify all DACM-B power feeds and ground circuits using the vehicle-specific wiring diagram.
Repair missing power or poor ground before continuing with communication-network diagnosis.
5. Inspect the Module Connector
Inspect the connector for corrosion, bent pins, loose terminals, damaged locking tabs, contamination, or water intrusion.
6. Test the Communication Network
If power and ground are correct, test the applicable communication network according to the manufacturer's diagnostic procedure.
7. Check Related Modules
Check the radio, display, gateway, amplifier, infotainment module, and other related modules for additional communication codes.
Multiple U-codes can indicate a broader network problem rather than a failure of DACM-B alone.
8. Consider Module Failure Last
Only after the fuse, power supply, ground, connectors, wiring, and communication network have been verified should Digital Audio Control Module B itself be considered defective.
U0194 Diagnostic Signal Flow
↓
Fuse Box
↓
Power & Ground
↓
Digital Audio Control Module B
↓
Vehicle Communication Network
↓
Gateway / Related Modules
↓
Audio / Infotainment Functions
U0194 Signal Flow
↓
DACM-B Wakes Up
↓
Digital Audio Processing / Control
↓
Network Communication
↓
Gateway / Other Modules
↓
Audio / Infotainment Functions
U0194 Multimeter Testing
A digital multimeter (DMM) can be used to check the electrical conditions that may cause U0194. Exact test points, voltages, and resistance specifications must come from the vehicle-specific service information.
Power Supply Test
- Set the multimeter to DC voltage.
- Connect the black probe to a known-good ground.
- Measure each DACM-B battery power supply.
- Measure ignition or accessory power when applicable.
- Compare the readings with manufacturer specifications.
If expected voltage is missing, trace the circuit toward the fuse, relay, power-distribution system, ignition circuit, or wiring harness.
Ground Voltage-Drop Test
A voltage-drop test can identify excessive resistance in the DACM-B ground circuit.
- Set the multimeter to DC voltage.
- Place the positive probe on the module ground circuit.
- Place the negative probe on battery negative.
- Operate the system under the appropriate load.
- Compare the voltage drop with the manufacturer's specification.
Do not use a single universal voltage-drop limit for every vehicle.
CAN Voltage Test
If the vehicle uses high-speed CAN communication, a multimeter can provide a preliminary indication of CAN-bus voltage conditions.
A typical high-speed CAN network has a recessive level around 2.5 V, while CAN-H and CAN-L move in opposite directions during dominant signaling. Typical reference levels are approximately 3.5 V on CAN-H and 1.5 V on CAN-L.
These are only typical reference values. Always use the manufacturer's specifications for the specific vehicle.
CAN Resistance Test
With the vehicle powered down according to the manufacturer's procedure, a properly terminated high-speed CAN network may measure approximately 60 Ω between CAN-H and CAN-L.
This value is associated with two 120 Ω termination resistors connected in parallel. Other network architectures may produce different readings.
U0194 OBD Live Data
A professional scan tool may provide module communication status, system voltage, network status, module availability, audio-system parameters, and other vehicle-specific information.
Check whether DACM-B appears as an active network node. If it is completely unavailable while other modules communicate normally, focus on its power, ground, connector, and communication circuits.
U0194 Oscilloscope Testing
An oscilloscope can provide a more detailed view of communication signals than a multimeter. If DACM-B uses CAN communication, inspect CAN-H and CAN-L at the appropriate test points and compare the waveform with the manufacturer's specifications.
Normal CAN Communication
CAN-L ‾‾\__/‾‾\__/‾‾\__/‾‾\__/‾‾
Possible Communication Fault
CAN-L ─────────────────────────
Possible causes:
- Open circuit
- Short circuit
- Bus-off condition
- Loss of module power
- Network fault
Is U0194 Serious?
U0194 is generally a low-to-moderate severity fault when it is isolated to the digital audio system. The immediate effect is usually loss of audio or infotainment functionality rather than a direct engine-control problem.
However, if U0194 appears with multiple communication codes, warning lights, or other modules becoming unavailable, the underlying network or power problem should be diagnosed promptly.
Can I Drive With U0194?
If U0194 is isolated to Digital Audio Control Module B and the vehicle operates normally, driving is generally possible. The main effects are normally related to audio or infotainment functions.
If multiple control modules report communication failures, the vehicle should be diagnosed promptly to identify the common power, ground, gateway, or network problem.
U0194 Repair Cost
- Electrical diagnosis: approximately $50–$150+.
- Fuse or power repair: approximately $20–$150+.
- Wiring or connector repair: approximately $50–$300+.
- Used module: approximately $50–$300+.
- New or remanufactured module: approximately $150–$800+.
- Programming or configuration: additional cost may apply.
These are general estimates only. Actual repair costs depend on the vehicle, module design, parts availability, labor rate, and programming requirements.
Digital Audio Control Module B Replacement
If DACM-B is confirmed to be defective, the replacement procedure depends on the vehicle. The module may be located behind the dashboard, near the audio system, inside the center console, or integrated into another infotainment assembly.
Some vehicles require programming, configuration, initialization, calibration, or security procedures after module replacement.
Before replacement, confirm the correct module part number and compatibility with the vehicle's model year, audio system, equipment level, and network configuration.
Common Repair Mistakes
- Replacing DACM-B before checking its fuse.
- Failing to verify module power and ground.
- Assuming U0194 automatically means the radio is defective.
- Ignoring connector corrosion.
- Ignoring communication wiring.
- Failing to scan all control modules.
- Ignoring low system voltage.
- Replacing the module before checking related communication codes.
- Applying generic CAN specifications without checking the vehicle architecture.
- Installing a replacement module without checking programming requirements.
Related Codes
- U0193 – Lost Communication With Digital Audio Control Module A.
- U0194 – Lost Communication With Digital Audio Control Module B.
These are the directly related codes in the Digital Audio Control Module A/B group. Other audio, radio, amplifier, or infotainment U-codes may also appear depending on the vehicle architecture.
FAQ About U0194
What does U0194 mean?
U0194 means Lost Communication With Digital Audio Control Module B. The vehicle has detected that expected communication with DACM-B has been lost.
What is DACM-B?
DACM-B stands for Digital Audio Control Module B. It identifies the electronic network module associated with the U0194 fault.
Does U0194 mean the radio is bad?
No. U0194 can be caused by a fuse, missing power, poor ground, communication wiring fault, connector problem, low voltage, network fault, software/configuration problem, or an internal module failure.
Can a blown fuse cause U0194?
Yes. If DACM-B loses its required power supply because of a blown fuse or an open power circuit, other modules may detect that communication with it has been lost.
Can wiring cause U0194?
Yes. An open circuit, short circuit, high resistance, damaged connector, or corrosion in the communication wiring can interrupt communication with DACM-B.
Can low battery voltage cause U0194?
Low or unstable system voltage can cause electronic modules to shut down or lose communication. Battery and charging-system condition should therefore be checked when U0194 appears with voltage-related symptoms or additional communication codes.
Can a multimeter diagnose U0194?
A multimeter can verify power, ground, voltage drop, fuse voltage, and preliminary communication-circuit conditions. An oscilloscope can provide more detailed analysis when communication waveform testing is required.
Where is Digital Audio Control Module B located?
The location varies by vehicle. It may be behind the dashboard, near the audio system, inside the center console, or integrated into another infotainment component. Always use the vehicle-specific service information.
Does U0194 affect engine performance?
When U0194 is isolated to the digital audio system, it generally does not directly affect engine operation. However, additional communication codes should be diagnosed to rule out a broader vehicle-network problem.
Does a replacement DACM-B need programming?
Some vehicles require programming, configuration, initialization, calibration, or other setup procedures after replacement. The exact requirement depends on the manufacturer and vehicle configuration.
Final Takeaway
U0194 means Lost Communication With Digital Audio Control Module B, also referred to as DACM-B.
The code identifies a communication problem and does not automatically prove that the module itself has failed. The correct diagnostic sequence is to check the fuse, power supply, ground, connectors, communication wiring, network integrity, system voltage, and related modules before replacing DACM-B.
A multimeter can be used to verify power, ground, voltage drop, and basic circuit conditions, while an oscilloscope can provide more detailed communication waveform analysis when required.
Diagnose the complete communication path first, then condemn Digital Audio Control Module B only after the external electrical and network circuits have been proven good.