U0619 code meaning
Lost Communication With Reductant Level Sensor A
Network system Generic code U06xx codes Check engine light
What U0619 means
Reductant level sensor A reports how much diesel exhaust fluid (DEF, AdBlue) is left in the SCR tank. Newer tank units are smart sensors: a sensing element plus electronics that transmit level, temperature and often concentration as digital frames over CAN, SENT or LIN. U0619 means the engine or aftertreatment controller gets no valid frames from that level sensor, whether the line is silent, frames time out, checksums fail or the sensor flags an internal fault. CARB requires a digital input that stops talking to store its own code, apart from the circuit and plausibility codes P203A to P203E. No manufacturer publicly documents a detection rule for U0619. Without a level value the low-DEF warning is lost and the controller can no longer rule out an empty tank, which California treats as an SCR fault.
U0619 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0619
- Check engine light or SCR warning
- DEF gauge blank or frozen at a fixed value
- No warning before the DEF tank runs empty
Common causes of U0619
- Most likelyCorroded, water-soaked or loose connector at the DEF tank sensor
- PossibleData line, supply or ground of the tank sensor chafed or broken along the frame
- PossibleElectronics of the tank level sensor failed (often replaced as a tank sender unit)
- Less likelyController software or configuration not matching the installed sensor
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant level sensor aSensor wiring
What each part of U0619 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 19 | The exact fault in that area. |
What to do next
- Note U0619 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 U0619
What does U0619 mean?
U0619 means "Lost Communication With Reductant Level Sensor A". Reductant level sensor A reports how much diesel exhaust fluid (DEF, AdBlue) is left in the SCR tank. It is a generic code, so it means the same on every make.
Is it safe to drive with U0619?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will U0619 fail an emissions test?
Yes, it can. U0619 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U0619 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U0619 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.