U0191 — Data Bus: Television – No Communication #

Note: The code label may vary depending on the vehicle manufacturer.

• No Communication with TV Control Module (BMW, Mercedes-Benz)
• Lost Communication With Rear Entertainment Control Module (Ford, Lincoln)
• Television Module Communication Malfunction (Jaguar, Land Rover)
• No Communication with Multimedia Control Unit (Volkswagen, Audi)

Summary of Code U0191 #

The U0191 fault code is a generic communication-related Diagnostic Trouble Code (DTC) that means the vehicle’s main control modules are unable to communicate with the television or rear entertainment module via the data bus. In modern vehicles, modules such as the Body Control Module (BCM) and Powertrain Control Module (PCM) exchange data over the Controller Area Network (CAN) bus. If the TV or entertainment module fails to reply or cannot be reached, this code is triggered. The code itself does not point to a specific failed component but rather to a communication breakdown. Consequences can range from loss of rear entertainment functionality to potential data traffic issues on the vehicle’s network.

Common Symptoms for Code U0191 #

When U0191 appears, you may notice a loss of access to certain multimedia or entertainment features. Some drivers might not see any immediate issues beyond a warning light, while others may find rear screens or infotainment systems unresponsive. The exact impact depends on your vehicle and equipment level.

• Rear seat entertainment system not working
• No picture or sound from TV module
• Infotainment display shows error messages
• Check Engine or Service Warning Light may illuminate
• Navigation or audio features partially disabled

Most Probable Causes for Code U0191 #

The most common causes for code U0191 are related to wiring or connector issues, module power supply faults, or software glitches. Sometimes, a recent battery replacement or jump-start event can also trigger network communication errors. Here are the most probable causes in order of likelihood:

1. Loose, corroded, or damaged data bus wiring/connectors
2. Faulty TV or rear entertainment control module
3. Power or ground supply issues at the affected module
4. CAN bus network interruption or short
5. Module software or firmware mismatch
6. Incorrectly performed battery replacement or jump-start

Step-by-Step Diagnostic for Code U0191 #

Proper diagnosis ensures you don’t waste time or money swapping parts unnecessarily. If you have access to a scan tool and some basic tools, follow these steps:

• 1. Confirm the code and clear it. Use an OBD-II scan tool to read and clear the code. If it returns, proceed with diagnosis.
• 2. Check for related codes. Look for other U-codes or B-codes that may point to network-wide issues.
• 3. Inspect wiring and connectors. Focus on the TV/entertainment module and CAN bus connections. Look for bent pins, loose plugs, corrosion, or frayed wires.
• 4. Verify module power and ground. Using a multimeter, ensure the module is receiving proper voltage and has a good ground.
• 5. Test data bus continuity. Check for continuity and proper resistance (usually 60 ohms across CAN lines when powered down).
• 6. Substitute/Bypass module if possible. If all wiring checks pass, try connecting a known-good module or bypassing the TV module (if possible) to see if network communication is restored.
• 7. Update/reprogram module software. Consult OEM service information for any known software-related bulletins or updates.

Possible Repairs for Code U0191 #

Repairs will directly relate to the root cause identified during diagnostics. Address wiring and connection problems first; only replace modules as a last resort after verifying all other possibilities.

• Repair or replace damaged CAN bus wiring/connectors
• Clean and secure all module connectors
• Restore or repair module power and ground circuits
• Replace faulty TV or entertainment control module
• Update module software as per OEM recommendations
• Check battery condition and correct improper installations

Is It Safe to Drive with Code U0191? #

Generally, YES — with limitations. Code U0191 rarely affects basic vehicle operation or safety systems. Your car will usually drive normally, but rear entertainment functions or infotainment features may be limited or unavailable. It’s safe to drive to your destination, but schedule a diagnostic soon to restore full multimedia function and ensure no related network issues are present.

Vehicles Most Commonly Affected by U0191 #

This code is most often found in vehicles equipped with factory rear entertainment or TV modules, especially in the luxury segment. OEMs using multi-module CAN bus networks are more likely to log U0191, particularly:

• BMW 5, 6, 7 Series (E60/E65/E66/F01)
• Mercedes-Benz S-Class, E-Class (with Rear Entertainment)
• Ford Expedition, Lincoln Navigator
• Jaguar XJ, Range Rover, Land Rover Discovery
• Audi A6, Q7 (with MMI Rear Seat Entertainment)
• Volkswagen Touareg, Phaeton

Frequent Mistakes & Best Practices for Code U0191 #

Rushing to replace the TV or entertainment module is a common misstep. Network codes are often caused by simple wiring faults, connector issues, or software glitches. Here’s how to avoid common errors:

• Don’t replace modules before verifying wiring and power/ground supply.
• Always check for TSBs (Technical Service Bulletins) about software updates.
• Label and reconnect all wiring correctly after battery or module work.
• Use dielectric grease on connectors to prevent future corrosion.
• After repairs, always clear codes and verify that communication is restored.

FAQ Express: U0191 #

Q: Can U0191 cause my car not to start?
A: No, U0191 is related to multimedia or entertainment systems, not starting or engine controls. If your car won’t start, check for other codes.

Q: Will a dead battery trigger U0191?
A: It’s possible. If the battery was recently replaced or discharged, modules may lose communication temporarily. Clearing the code after restoring battery condition may resolve the issue if no wiring or module fault exists.