The part is the advanced emissions control solution for the HOWO MAX 4X2 tractor, designed to reduce nitrogen oxide emissions through selective catalytic reduction technology. This genuine HOWO SCR system kit includes the DCU assembly, urea nozzle, exhaust temperature sensor, urea pump box, pressure pipe, and all mounting hardware – engineered to meet China V emission standards. When you choose authentic Howo Parts, this SCR system guarantees precise dosing, reliable performance, and full compliance with environmental regulations. Below are detailed descriptions of every component included with this SCR system.
The DCU assembly is the control unit of The part, managing the urea injection process and monitoring system performance. This SCR system component receives signals from the exhaust temperature sensor and the NOx sensors to calculate the precise urea dosage. The DCU communicates with the engine ECU via CAN bus, ensuring coordinated operation. It also stores fault codes and provides diagnostic data, making it an essential part of The part for maintaining emission compliance.
The urea nozzle is a precision pneumatic injector that atomises the urea solution into the exhaust stream. This SCR system nozzle has a 1.0mm orifice and is calibrated for China V applications, delivering a fine spray pattern that ensures optimal mixing with exhaust gases. The nozzle is made from corrosion‑resistant stainless steel and includes a built‑in air‑assist feature for improved atomisation at low flow rates.
The exhaust temperature sensor is a thermocouple probe that measures the gas temperature upstream of the SCR catalyst. This SCR system sensor provides critical data to the DCU, enabling the system to calculate the optimal urea injection quantity. The sensor is rated for temperatures up to 900°C and is sheathed in stainless steel for durability. Accurate temperature measurement is vital for The part to achieve the required NOx conversion efficiency.
Two M8 hexagon flange bolts are supplied to secure the urea pump box and other components of The part. These bolts feature an integral flange that distributes clamping load evenly, eliminating the need for separate washers. They are grade 8.8 with a zinc‑plated finish, torqued to 25 Nm, ensuring a vibration‑proof attachment for The part.
Two M8 hex flange nuts are used with the M8 bolts to secure The part components. The flange acts as a built‑in washer, providing a large bearing surface and a self‑locking action that resists loosening. These nuts are made from zinc‑plated steel and are torqued to 25 Nm, ensuring The part remains securely mounted.
The urea pump box is a self‑contained unit that houses the electric pump, filter, and pressure regulator for The part. This integrated system is designed for China V non‑heating applications, drawing urea from the tank and delivering it at the required pressure to the nozzle. The pump box is compact and weather‑sealed, with quick‑connect fittings for easy installation. It is a critical component of The part, ensuring consistent urea flow and pressure.
The pressure pipe is a 2750mm long, high‑pressure hose that carries urea from the pump box to the nozzle. This SCR system pipe is made from reinforced nylon with a stainless steel braid, rated for 10 bar working pressure. It includes crimped end fittings that seal against the pump and nozzle connections. The pipe is flexible yet durable, capable of withstanding the under‑chassis environment of The part.
The SCR adblue is the reducing agent used in The part to convert NOx into nitrogen and water. Fifteen units of high‑purity urea solution (32.5% concentration) are supplied, meeting ISO 22241 standards. This AdBlue is essential for The part to achieve the required NOx reduction, and using genuine AdBlue ensures The part operates without deposit formation or catalyst poisoning.
SCR system – genuine HOWO complete selective catalytic reduction kit for MAX 4X2
This SCR system kit includes the DCU, nozzle, sensor, pump box, pressure pipe, and AdBlue – every component needed for a full SCR system installation. The part is pre‑calibrated for China V emissions, ensuring your HOWO MAX 4X2 remains compliant and efficient.
The part uses a 1.0mm pneumatic nozzle and a closed‑loop control strategy to deliver the exact urea quantity required. This SCR system achieves NOx conversion rates of over 95%, reducing tailpipe emissions to meet the strictest standards.
The urea pump box is a self‑contained unit that maintains a constant pressure to the nozzle, ensuring consistent spray quality. The part pump box is designed for non‑heating applications, making it ideal for moderate climates where freeze protection is not required.
This SCR system comes with all mounting bolts, nuts, and 15 units of high‑quality AdBlue. No additional parts are needed for installation, making The part a convenient, all‑in‑one solution for your HOWO MAX 4X2.
The part functions by injecting a precise amount of urea solution (AdBlue) into the exhaust stream upstream of the SCR catalyst. The urea decomposes into ammonia, which reacts with NOx over the catalyst to form nitrogen and water vapour. The DCU assembly continuously monitors exhaust temperature and NOx levels to adjust the urea injection rate.
The exhaust temperature sensor provides critical data to ensure the catalyst is at optimal temperature for The part reaction. The urea pump box delivers the AdBlue at a controlled pressure, and the pneumatic nozzle atomises the fluid for efficient mixing.
The pressure pipe connects the pump box to the nozzle, ensuring a reliable supply. Proper maintenance of The part, including regular AdBlue top‑up and periodic cleaning of the nozzle, is essential for sustained performance. A well‑maintained SCR system not only reduces emissions but also improves fuel economy by allowing the engine to operate at optimal timing without NOx penalties.
Before installing The part, ensure the vehicle is on level ground and the exhaust system is cool. Mount the urea pump box securely to the chassis using the M8 flange bolts and nuts, torquing to 25 Nm. Install the DCU assembly in a protected location near the engine ECU, connecting the CAN bus and power wiring. Screw the exhaust temperature sensor into the exhaust pipe upstream of the SCR catalyst, using a copper washer to ensure a gas‑tight seal. Route the pressure pipe from the pump box to the nozzle,
avoiding sharp bends and hot surfaces. Secure the pipe with the provided clips. Connect the nozzle to the pressure pipe and mount it in the exhaust pipe, ensuring the spray angle is correct.
Fill the urea tank with the supplied AdBlue. Connect all electrical connectors and ensure the system is properly grounded. Start the engine and perform a leak test. Check for any diagnostic trouble codes using a scan tool. The part is now ready for service. Note that The part may require a drive cycle to complete the initialisation.
If The part triggers a warning light, check the AdBlue level first. Low AdBlue will cause The part to deactivate and limit engine performance. If the AdBlue level is sufficient, inspect the pressure pipe for leaks or kinks. A blocked nozzle can cause poor atomisation; remove and clean the nozzle with compressed air. If the exhaust temperature sensor reads incorrectly,
The part may not dose accurately; test the sensor resistance. Electrical faults in the DCU or wiring can cause communication errors; check the CAN bus connections. If The part fails to prime,
check the pump box fuse and ensure the pump is receiving power. Always use genuine AdBlue to prevent deposit formation. For persistent faults, consult a diagnostic tool to read The part fault codes. Repairs to The part should only be performed by trained technicians.
Inspect The part every 50,000 km or annually. Check the AdBlue level and top up with genuine fluid as needed. Inspect the pressure pipe for chafing or cracks; replace if damaged. Clean the urea nozzle with a suitable cleaning solution to prevent clogging.
Check the exhaust temperature sensor for damage and ensure it is securely mounted. The DCU assembly should be checked for any software updates. Replace the urea filter (if equipped) according to the manufacturer’s schedule. Keeping The part clean and properly maintained ensures it continues to reduce emissions effectively and prolongs the life of the catalyst.
This SCR system is specifically designed for the HOWO MAX 4X2 tractor with China V emission standards. It is compatible with MC11 and MC13 engines and fits all production years from 2018 onward. The system is also suitable for SITRAK C7H and HOWO T7H models that share the same SCR architecture.
It is not compatible with older China IV systems or vehicles with different urea pump configurations. Always verify your vehicle’s emission standard and engine type before ordering The part. The AdBlue quantity supplied (15 units) is sufficient for approximately 5,000 km of normal operation.
Aftermarket SCR system components often use inferior urea pumps that fail prematurely, leading to costly breakdowns and failed emission tests. Non‑genuine nozzles may not atomise correctly, causing urea deposits that block the catalyst.
Generic temperature sensors may have incorrect resistance values, causing the DCU to miscalculate dosing. Genuine HOWO SCR system components are manufactured to SINOTRUK’s exacting standards, using certified materials and precision engineering.
The small additional cost of a genuine SCR system is insignificant compared to the cost of a failed emission test or a damaged catalyst. For fleet operators, using genuine SCR systems ensures consistent compliance and reduces the risk of roadside inspections and fines.
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