U0073 on Cadillac: How to Diagnose & Fix
Control Module Communication Bus Off
1 Cadillac model · 1 documented issue · $150-$500 repair
U0073 on Cadillac by model: symptoms, diagnosis and fix
The Safety Alert Seat uses haptic (vibration) motors in the left and right seat bolsters to pulse warnings for lane departure, blind spot, and forward collision. One side commonly stops vibrating (left or right only), or the system randomly switches between vibrate and chime. The documented weak point is a wire breaking where it enters the haptic motor assembly. Because GM ties this hardware into the driver-assist suite, a failed seat motor frequently also triggers a 'Service Driver Assist System' message.
Common Symptoms
- No vibration on one side of seat
- Seat randomly switches to chime instead of buzz
- Service Driver Assist System message
- Lane-departure/blind-spot light flashes but no buzz
- Inconsistent forward-collision haptic
How to Fix
Confirm the dead side by triggering lane-departure to each side; if only one bolster pulses, the opposite motor/wire has failed. Replace the affected seat haptic vibration motor (left or right bumper-alert motor) and repair the broken wire at the motor entry. If the seat hardware checks out, scan the BCM for driver-assist codes and update software, since a glitch can mimic the failure. As a stopgap, owners can switch Alert Type to 'beeps' in the menu to restore audible warnings.
Sources for this issue (1)
U0073 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0073 mean on a Cadillac?
U0073 stands for "Control Module Communication Bus Off." U0073 means the vehicle's communication bus has shut down, or 'gone off,' meaning a control module detected so many errors on the network that it stopped transmitting to protect the bus. On a CAN network, repeated faulty signals cause a module to take itself offline, which can cascade into multiple warning lights and disabled features. This is a network/wiring code rather than a single failed sensor, and it usually points to a wiring short, a defective module flooding the bus, or a power/ground issue affecting communication. It often requires checking the whole bus circuit, not just one part. On Cadillac it is documented across 1 model: XTS.
What are the most common causes of U0073?
The most common causes of U0073 are: Short to power or ground on the CAN bus wiring, CAN high/low wires shorted together, A failing module continuously corrupting bus traffic, Corroded, loose, or damaged bus connectors, Loss of power or ground to a network module, Faulty gateway/central communication module, Improper or missing bus terminating resistor. The specific cause varies by vehicle.
How much does it cost to fix U0073 on a Cadillac?
Published repair estimates on Cadillac range from $150 to $500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for U0073 on a different make?
View U0073 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.