A failing sunroof control module that is sending corrupted or out-of-range data onto the network.; Damaged or chafed wiring in the harness that runs through the body to the sunroof module, often at the hinge or pillar area.; Corroded or loose electrical connectors at the sunroof module or at a network splice point.; Low battery voltage or a weak charging system causing the module to boot improperly and transmit invalid frames.; Water intrusion into the sunroof module or its connector, common after clogged drain tubes or a leaking seal.; A network communication fault such as a shorted data bus wire that corrupts messages from the sunroof module.; An aftermarket accessory wired into the sunroof circuit that introduces electrical noise or improper voltage.

DTC codes / U04xx · Invalid data received from a module / U046A

U046AInvalid Data Received From Sunroof Control Module

Q: What does code U046A mean?

Invalid Data Received From Sunroof Control Module. U046A is a generic communication fault indicating that a control module on the vehicle's network received invalid or corrupted data from the sunroof control module. The computer detected a message from the sunroof module that failed its internal checksum or contained data outside the expected range, so it flagged the signal as untrustworthy rather than treating it as a valid command.

U046A is a generic communication fault indicating that a control module on the vehicle's network received invalid or corrupted data from the sunroof control module. The computer detected a message from the sunroof module that failed its internal checksum or contained data outside the expected range, so it flagged the signal as untrustworthy rather than treating it as a valid command.

SystemNetwork

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaInvalid data received from a module

Symptoms you may notice

The sunroof may stop responding to the switch or move in short, jerky increments.
The sunroof may fail to close completely or reverse direction unexpectedly during operation.
A warning light or message on the dashboard, often accompanied by a chime.
Other body control functions such as interior lights or power windows may behave erratically if they share the same network segment.
Often no symptoms besides the warning light, with the sunroof operating normally.
The sunroof may lose its one-touch open or close feature and require the switch to be held.

Common causes, most likely first

A failing sunroof control module that is sending corrupted or out-of-range data onto the network.
Damaged or chafed wiring in the harness that runs through the body to the sunroof module, often at the hinge or pillar area.
Corroded or loose electrical connectors at the sunroof module or at a network splice point.
Low battery voltage or a weak charging system causing the module to boot improperly and transmit invalid frames.
Water intrusion into the sunroof module or its connector, common after clogged drain tubes or a leaking seal.
A network communication fault such as a shorted data bus wire that corrupts messages from the sunroof module.
An aftermarket accessory wired into the sunroof circuit that introduces electrical noise or improper voltage.

How to diagnose and fix it

Verify battery voltage and charging system output, then clear the code and retest to see if it returns under normal voltage.
Inspect the sunroof module connector and surrounding harness for corrosion, water stains, or loose pins, and clean or reseat as needed.
Check the sunroof drain tubes and seals for leaks that could allow water to reach the module or connectors.
Perform a wiggle test on the harness while watching live data for the sunroof module to catch intermittent wiring faults.
Measure resistance and voltage on the network data bus at the sunroof module to confirm the module is transmitting valid signals.
If wiring and power are confirmed good, substitute a known-good sunroof control module and recheck for the code.
After repair, perform any required sunroof normalization or calibration procedure so the module relearns its end stops.

What technicians miss on U046A

A weak or failing battery is a frequent culprit because the sunroof module may transmit invalid data during low-voltage cranking events, and the code sets even though the module itself is healthy.
Water damage from clogged sunroof drains often corrodes the module connector long before the module fails, so inspecting for moisture is more productive than replacing parts.
The code can be set by a corrupted message caused by a shorted data bus wire elsewhere on the network, meaning the sunroof module is the victim rather than the cause.
Aftermarket sunroof deflectors or phone chargers plugged into the same circuit can introduce electrical noise that corrupts network messages and triggers this code intermittently.
Clearing the code without performing a sunroof normalization procedure can leave the module in a confused state that immediately resets the same fault.

Can I keep driving with U046A?

The vehicle remains safe to drive because the sunroof is a comfort feature and the fault does not affect steering, braking, or powertrain operation. Avoid operating the sunroof repeatedly until the fault is diagnosed, and keep the roof closed during rain in case the module fails to respond.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.