Lost Communication with Reductant Control Module
The U010E code indicates that the vehicle's main control module (typically the ECM/PCM) has lost communication with the Reductant Control Module (RCM). The RCM manages the Selective Catalytic Reduction (SCR) system, which injects Diesel Exhaust Fluid (DEF) to reduce nitrogen oxide (NOx) emissions in diesel vehicles. This loss of communication can be caused by faults in the CAN bus data network, electrical interruptions, or internal failure of the RCM itself. According to SAE J2012, U-codes in the U0100-U0299 range relate to data bus communication issues.
1. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.
2. Most Common Causes
- Faulty wiring or connectors in the CAN bus circuit to the RCM
- Blown fuse in the RCM power supply circuit
- Internal failure of the Reductant Control Module (RCM)
- Poor ground connection at the RCM
- Electromagnetic interference on the communication bus
- Corrosion or damage to module connectors
- Incomplete or failed software update of the RCM
3. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Increased diesel exhaust fluid (DEF) consumption or warning
- Poor fuel economy and increased emissions
4. Step-by-Step Diagnosis
Scan for all stored codes and freeze frame data
Inspect the RCM power and ground circuits for voltage and continuity
Check CAN bus wiring and connectors for damage, corrosion, or shorts
Test communication at the RCM using a scan tool or oscilloscope
If wiring is intact, attempt to reprogram or replace the RCM
5. Frequently Asked Questions
Is it safe to drive?▼
No, it is not recommended to drive with this code. The vehicle may enter limp mode, and continued operation could damage the SCR system or cause non-compliance with emissions regulations.
How much does it cost to fix?▼
Repair costs typically range from $200 to $1,200, depending on whether the issue is a simple fuse or wiring repair versus replacement of the RCM module.