BMW DTC U02A2 – Lost Communication with Reductant Quality Module
DTC U02A2 meaning on BMW
The Diagnostic Trouble Code (DTC) U02A2 on a BMW indicates a communication error between the vehicle’s control module and the Reductant Quality Module. The Reductant Quality Module is responsible for monitoring the quality of the diesel exhaust fluid (DEF) used in the Selective Catalytic Reduction (SCR) system.
BMW DTC U02A2 symptoms
Symptoms of the DTC U02A2 on a BMW may include:
- Check Engine Light (CEL) illuminated
- Reduced engine performance
- Increased fuel consumption
- Failure to pass emissions tests
BMW DTC U02A2 causes
Common causes of the DTC U02A2 on a BMW include:
- Faulty Reductant Quality Module
- Wiring or connection issues between modules
- Software glitches or updates
BMW DTC U02A2 seriousness
The DTC U02A2 is considered a moderate issue. While it may not cause immediate harm to the vehicle, it can lead to reduced engine performance and increased emissions if left unresolved. It is recommended to address this issue promptly to prevent further complications.
How to diagnose DTC U02A2 on BMW
To diagnose the DTC U02A2 on a BMW, a mechanic would typically perform the following steps:
- Use a diagnostic scanner to retrieve the fault codes
- Inspect the wiring and connections between the control module and Reductant Quality Module
- Check for any software updates or glitches
How to fix DTC U02A2 on BMW
To fix the DTC U02A2 on a BMW, the following steps may be taken:
- Replace the faulty Reductant Quality Module
- Repair any damaged wiring or connections
- Update the software to the latest version
How to erase DTC U02A2 on BMW
To erase the DTC U02A2 on a BMW, a mechanic can use a diagnostic scanner to clear the fault codes stored in the vehicle’s system. Once the issue has been resolved and the codes cleared, the Check Engine Light should turn off.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
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