U043E code meaning
Invalid Data Received From Vacuum Sensor A
What U043E means
Vacuum sensor A reports the vacuum in a brake booster or vacuum reservoir; U043E is meant for designs in which this sensor sends digital messages and a receiver judges them invalid. No manufacturer documents U043E publicly. GM's usual layout uses an analogue booster vacuum sensor with P-codes: bulletin 17-NA-314 for 2018 Enclave and Traverse traces a Service Power Brake Assist message and brake shudder to wrong readings from a faulty sensor circuit board, setting P0557 and C025E, and 16-NA-366 for 2014-16 Encore links a hard pedal and a constantly running vacuum pump to contamination in sensor, check valve and hose. Comparable effects are plausible with U043E: brake assist warnings, a longer running vacuum pump or start-stop held off. U013D is lost contact; sensor B has U043F.
U043E at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U043E
- Brake assist warning message
- Hard brake pedal or vacuum pump running often
Common causes of U043E
- PossibleFaulty sensor electronics giving wrong vacuum values
- PossibleOil or dirt in the sensor, check valve or vacuum hose
- Less likelyPoor terminal tension at the sensor connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Vacuum sensor a
What each part of U043E means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3E | The exact fault in that area. |
What to do next
- Note U043E 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 U043E
What does U043E mean?
U043E means "Invalid Data Received From Vacuum Sensor A". Vacuum sensor A reports the vacuum in a brake booster or vacuum reservoir; U043E is meant for designs in which this sensor sends digital messages and a receiver judges them invalid. It is a generic code, so it means the same on every make.
Is it safe to drive with U043E?
U043E does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U043E fail an emissions test?
U043E 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 U043E to fix?
Difficulty: medium. A typical repair takes 0.3 to 1.5 hours of work. This is a job for a workshop.
Will U043E clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.