U0156 Code: Lost Communication With Information Center "A"
The main information display or head unit dropped off the network; screen, radio or camera may be dead.
Unverified: this manufacturer-specific definition comes from a single source or varies by model. Confirm it with a brand-specific scan tool.
At a glance
Severity: Low
- Meaning
- Lost Communication With Information Center "A"
- System
- Module Communication · Network
- Safe to drive?
- Yes, short term
- Typical repair cost
- $0–$1,500
- DIY difficulty
- Easy
U0156 is set when other modules stop receiving messages from information center "A", the display unit that shows vehicle information to the driver. Which module that is varies by manufacturer: on many vehicles it is the center touchscreen or radio/infotainment head unit behind the dash, on others a separate driver information display or the display section of the cluster. When it drops out, you typically lose the center screen, radio, navigation, Bluetooth, the backup camera image and any settings that live in the touchscreen. The most common triggers are a head unit that crashed or got stuck during a software update, a blown radio or display fuse, low battery voltage and aftermarket stereos that replaced the original unit. Check the service information to confirm what information center "A" is on your model.
Can I keep driving? The car is safe to drive; engine, brakes and steering don't depend on this display. Be careful when reversing if the backup camera is out, and check that you can still set the defroster if climate controls are in the touchscreen.
How to read U0156
- U Network
- 0 Generic (SAE)
- 1 Module Communication
- 56 Specific fault
Symptoms
- Center screen black, frozen or rebooting in a loop
- No radio, navigation, Bluetooth or phone projection
- Backup camera image missing when shifting into reverse
- Steering wheel audio buttons and voice control dead
- Climate or vehicle settings unavailable because they live in the touchscreen
- Clock, outside temperature or trip info missing from the display
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Head unit software crash, frozen screen or interrupted software update
- Blown radio/display fuse or poor power and ground behind the head unit
- Aftermarket stereo installed without the correct network interface, so the original module is missing
- Low battery voltage, jump start or deep discharge
- Internal head unit failure, often heat-related
- Loose connector or network wiring behind the dash
Diagnosis step by step
Confirm which unit is information center "A"
Look up the module list for your model; it may be the touchscreen, the radio head unit or a separate display. That tells you which box to test.
Tools: OBD-II scanner
Try a hard reset
Most head units have a reset: hold the power/volume button for 10 to 20 seconds, or turn the car off, open and close the driver's door and wait until the modules go to sleep. A unit that comes back and stays up only needed a restart.
Check fuses and battery
Test the radio, display and infotainment fuses with a meter, and confirm about 12.6 V at rest. A tired battery often makes infotainment units the first to reset.
Tools: Multimeter, Flashlight
Look for an aftermarket stereo
If the original radio was swapped for an aftermarket unit, the network still expects the old module. The install needs a vehicle-specific interface, or the module has to be removed from the car's configuration, to stop the code.
Tools: Screwdriver
Check power, ground and network at the head unit
Pull the head unit with trim tools and measure battery and ignition feeds, ground and the network signals at its connector. With supply and bus good but no response, the unit itself has failed.
Tools: Screwdriver, Multimeter
Update, repair or replace the unit
Dealers can reload software on many units that crash repeatedly. A failed unit can often be repaired by specialists; a replacement usually needs coding to the VIN and sometimes activation of navigation or anti-theft features.
Tools: OBD-II scanner
Where the parts are
- 1Battery
- 2Alternator
- 3Engine computer (ECM)
- 4CAN bus
- 5Transmission
- 6Wheel speed sensor
- 7High-voltage battery
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Hard reset / clear codes | Yes | $0–$60 |
| Replace radio/display fuse | Yes | $5–$80 |
| Software update of head unit | No | $100–$250 |
| Install correct interface for aftermarket stereo | No | $80–$250 |
| Repair or replace and code head unit/display | No | $350–$1,500 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Emissions / smog test impact
Usually passes
U0156 doesn't affect emissions testing and usually doesn't turn on the check engine light. It would only matter in a safety inspection if it also knocked out required indicators.
Frequently asked questions
What exactly is information center "A"?
It is the display module that shows information to the driver, but which physical unit that is depends on the manufacturer. On most modern cars it is the center screen or radio head unit, on others a separate driver display.
My screen came back after a restart. Do I still need a repair?
Not necessarily. If it stays working and the code doesn't return, it was a software hang. If it keeps freezing, ask for a software update before replacing hardware.
Why did U0156 appear after I installed an aftermarket stereo?
The other modules still expect messages from the factory unit. Without a proper vehicle interface they log a lost-communication code, and features like steering wheel controls or chimes may stop working.
Is it safe to drive without the backup camera?
Yes, but reverse carefully using mirrors and shoulder checks. Get the display fixed, because the camera is an important aid around children and obstacles.
Sources
- SAE J2012 – Diagnostic Trouble Code Definitions
- ISO 15031-6 – Road vehicles, diagnostic trouble code definitions (EOBD)
- Manufacturer public service information (cross-checked)
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy