U042A code meaning
Invalid Data Received From V2X Module
What U042A means
The V2X module is the radio node for vehicle-to-everything messaging with other cars, roadside units and the network, via DSRC/ITS-G5 or cellular C-V2X. U042A tells that another module gets frames from it but cannot use their content. No manufacturer documents U042A publicly. Ford's patent US 9,769,762 shows the wiring that makes such a code possible: the V2X module sits on the CAN data bus with head unit, assistance unit and other controllers, adapts its transmit power to vehicle speed and message type, and broadcasts warnings such as hard braking on request of the assistance unit. Received alerts travel the other way to display and assistance functions, and that inbound path is what U042A guards. Nothing here affects emissions, so no MIL is expected; connected warnings simply drop out. U011F is lost contact.
U042A at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyWorkshop only
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U042A
- Connected traffic or hazard warnings missing
- Message about unavailable connected services
Common causes of U042A
- PossibleV2X module or receiver software fault
- PossibleV2X module faulty, for example after a supply interruption
- Less likelyAntenna or positioning input problem leading to invalid status data
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
V2x module
What each part of U042A means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 2A | The exact fault in that area. |
What to do next
- Note U042A and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U042A
What does U042A mean?
U042A means "Invalid Data Received From V2X Module". The V2X module is the radio node for vehicle-to-everything messaging with other cars, roadside units and the network, via DSRC/ITS-G5 or cellular C-V2X. It is a generic code, so it means the same on every make.
Is it safe to drive with U042A?
U042A does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U042A fail an emissions test?
U042A is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U042A to fix?
Difficulty: workshop only. A typical repair takes 0.3 to 2 hours of work. This is a job for a workshop.
Will U042A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.