What it means
The reporting module has lost communication with the television tuner. It sets this code when expected messages from the tuner are not received for a specified time.
How it works
The television tuner receives vehicle power and communicates with other modules over the vehicle network so related entertainment functions can be controlled. U0191 is stored when the reporting module does not receive the tuner's expected messages before its communication timeout.
Common causes
Most likely first.
- Tuner power or ground fault
- Damaged or corroded network wiring or connectors
- CAN bus short or open circuit
- Television tuner failure
- Low battery voltage
Symptoms
- Television tuner or related entertainment functions unavailable
- Warning message
- Other communication codes
How to diagnose it
- Scan all modules and record freeze-frame information and communication codes to determine whether the fault is limited to the television tuner or part of a broader network or low-voltage problem.
- Check battery condition and charging voltage, because low system voltage can make the tuner drop offline.
- Inspect the tuner’s power, ground, and network connectors for poor seating, corrosion, or damaged wiring.
- Use the wiring diagram to check the network branch to the tuner for an open or short circuit.
- If the tuner has correct power and ground, test network activity at its connector and compare results with the manufacturer's specification.
Common fixes
- Reseat or clean a poor television tuner connector.
- Repair damaged tuner power, ground, or network wiring.
- Resolve a weak battery or charging-system problem.
- Repair a CAN bus fault on the tuner branch.
- Replace or reprogram the television tuner if circuit and network tests confirm it has failed.
Can I keep driving?
The fault usually affects television tuner or related entertainment functions rather than driving or emissions. Driving is generally unaffected unless other communication codes point to a separate impaired vehicle system.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.