U05A3 code meaning
Invalid Data Received From Reductant Quality Module
Network system Generic code U05xx codes Check engine light
What U05A3 means
A reductant quality module checks that the tank holds proper diesel exhaust fluid, a 32.5 % urea solution. SSI's TULC sensor, for example, derives concentration from the speed of sound and reports it with level and temperature over J1939 CAN to the dosing control unit. This code means those reports arrive but are rejected. FCA documents it for the 2019 Jeep Cherokee 2.2 diesel (EMEA): bulletin 18-088-20 reprograms the dosing control unit when U05A3 appears with a MIL, often together with P20F4/P20F5 consumption faults. CARB 1968.2 demands that every input used by the low-quality inducement be monitored. Ford sets U02A2 when the module's messages are missing for 5 s. The driver may see a DEF warning, and inducement can follow if it persists.
U05A3 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.3 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of U05A3
- Check engine light and DEF warning
- Reductant consumption faults stored alongside
- Possible speed or restart limitation if not fixed
Common causes of U05A3
- Most likelyDosing control unit software misreading the module (FCA reflash)
- PossibleQuality sensor fouled by crystals or contaminated fluid
- Less likelyCorroded connector at the DEF tank sender
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Reductant quality module
What each part of U05A3 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A3 | The exact fault in that area. |
What to do next
- Note U05A3 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 U05A3
What does U05A3 mean?
U05A3 means "Invalid Data Received From Reductant Quality Module". A reductant quality module checks that the tank holds proper diesel exhaust fluid, a 32.5 % urea solution. It is a generic code, so it means the same on every make.
Is it safe to drive with U05A3?
Drive gently and only to a workshop. With U05A3 the car can go into limp mode (reduced power) to protect itself.
Will U05A3 fail an emissions test?
Yes, it can. U05A3 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 U05A3 to fix?
Difficulty: medium. A typical repair takes 0.3 to 3 hours of work. This is a job for a workshop.
Will U05A3 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.