SCR Cleaning
Restore your Selective Catalytic Reduction catalyst to peak NOx conversion efficiency - reducing DEF consumption, cutting emissions, and keeping you compliant.
Service Overview
Professional Selective Catalytic Reduction (SCR) Catalyst Cleaning for Diesel Trucks
The Selective Catalytic Reduction (SCR) system is your truck's primary defence against NOx emissions. When the SCR catalyst becomes contaminated with ammonium sulphate deposits, phosphorus, or silica poisoning, NOx conversion efficiency drops - triggering warning lights, increased DEF consumption, and potential derate. Our professional SCR cleaning service removes these contaminants without damaging the catalyst substrate, restoring NOx conversion efficiency and keeping your truck emission-compliant.
- Removes ammonium sulphate deposits and catalyst poisons from the SCR substrate
- Restores NOx conversion efficiency to OEM specification
- Reduces abnormally high DEF (AdBlue) consumption
- Clears SCR-related fault codes and derate conditions
- Pre- and post-cleaning NOx conversion efficiency measurement
- EPA-certified process - safe for vanadium and zeolite catalyst formulations
Why Choose Us
Benefits of Our SCR Cleaning
Industry-leading service backed by expertise, technology, and reliability
Emission Compliance
A clean SCR converts NOx to nitrogen and water at designed efficiency, keeping your truck within regulatory emission limits.
Reduce DEF Consumption
A contaminated SCR requires excess DEF injection to compensate - cleaning brings consumption back to normal.
Prevent Derate
SCR faults can trigger engine derate and reduced power. Cleaning resolves the root cause and clears fault conditions.
EPA-Certified
Certified technicians, certified process - your SCR system cleaned in full compliance with emission standards.
How It Works
Our streamlined process ensures quality results with minimal downtime
01
NOx Efficiency Baseline
We measure pre-clean NOx conversion efficiency and log all SCR-related fault codes from the ECU.
02
SCR Removal
The SCR catalyst is carefully removed following OEM specifications to prevent substrate cracking.
03
Deposit Removal
Specialist cleaning removes ammonium sulphate, phosphorus, and silica contamination from the catalyst.
04
Post-Clean Verification
NOx conversion efficiency is re-measured and compared to OEM specification to confirm full restoration.
05
Reinstallation & Report
SCR is reinstalled, fault codes cleared, and a detailed service report with efficiency readings provided.
Frequently Asked Questions
Common questions about our SCR Cleaning service
The Selective Catalytic Reduction (SCR) system converts harmful NOx emissions into harmless nitrogen gas and water vapour using Diesel Exhaust Fluid (DEF / AdBlue) as a reductant. Over time, the SCR catalyst can become contaminated by ammonium sulphate deposits (from DEF crystallisation), phosphorus from engine oil, or silica contamination. These deposits reduce NOx conversion efficiency, leading to emission failures, increased DEF use, and potential derate conditions.
Common symptoms include: NOx efficiency fault codes (e.g. P20EE, P2BAD), SCR efficiency monitor warnings, abnormally high DEF consumption, engine derate or reduced power, failed emission roadside inspections, and DEF fluid warning lights even when the tank is full.
Most SCR contamination from ammonium sulphate and surface deposits can be resolved through professional cleaning, restoring the catalyst to near-OEM efficiency. Replacement is only required when the catalyst substrate has suffered physical damage (cracking from thermal shock) or irreversible catalyst poisoning from heavy phosphorus or lead contamination. Our pre-service inspection determines the correct course of action.
When the SCR catalyst is underperforming, the engine management system compensates by injecting more DEF to try to reach target NOx conversion levels. This excess DEF causes higher consumption and can also cause DEF crystallisation deposits within the system. Cleaning the catalyst restores efficiency, so the system reverts to the correct DEF injection rate.
SCR cleaning typically takes 6–24 hours from vehicle drop-off to reinstallation. The timeframe depends on contamination severity and the catalyst size. Our technician will advise on a specific turnaround time after the initial inspection.
Yes - as part of our SCR service, we inspect the DEF injector (doser), DEF lines, and the DEF quality sensor for contamination and blockages. DEF injector cleaning or replacement can be carried out at the same time if needed, ensuring the entire SCR system is restored to correct function.
Cleaning the SCR alongside the DPF is highly recommended when both units are due for service. The two systems are closely linked - a malfunctioning SCR increases exhaust temperatures that can affect DPF regeneration, and vice versa. A combined service ensures the entire aftertreatment system is balanced and functioning as designed.
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