New Holland ENG 3545 – Engine ECU: Info: SCR Dosing Valve Overheat Protection - Torque Limitation Level2 for SCR Protection active

The SCR Dosing Valve (DEF Injector) is overheating, triggering a Level 2 torque limitation to protect the system. This is typically caused by a failure in the cooling circuit or severe exhaust gas leakage around the injector tip.

• T6 Series
• T7 Series
• T8 Series
• T9 Series
• T8.275
• T8.300
• T8.360
• T8.390
• T7.220
• T7.270
• CR Series
• CX Series
• CR9090
• CX8080
• CX8090
• W190B

1. 1

   Check the main engine coolant reservoir level to ensure the DEF injector is not being starved of cooling supply

2. 2

   Inspect the coolant feed and return hoses running to the SCR dosing valve for pinched, kinked, or collapsed lines, blockages, or leaks

3. 3

   Check for air pockets in the doser coolant lines, especially if the cooling system was recently serviced

4. 4

   Inspect the coolant control valve (if equipped) to ensure it is opening properly and regulating coolant flow to the doser

5. 5

   Inspect the mounting flange where the dosing valve meets the exhaust decomposition tube for blown gaskets causing exhaust leaks

6. 6

   Remove the doser and inspect the nozzle for severe DEF crystallization that could insulate the tip and disrupt the spray pattern

1. 1

   Preparation

   Park the machine on a level surface, turn off the engine, and allow the exhaust system to cool down completely.

2. 2

   Drain Coolant

   Drain a small amount of engine coolant from the radiator petcock to lower the fluid level below the height of the DEF injector, preventing spills.

3. 3

   Disconnect Lines

   Carefully unplug the electrical wiring harness connector from the SCR dosing valve. Disconnect the DEF fluid supply line (cap the line immediately to prevent contamination). Disconnect the coolant inlet and outlet hoses from the valve.

4. 4

   Remove the Valve

   Remove the mounting bolts or the V-band clamp securing the dosing valve to the exhaust decomposition pipe. Pull the valve away from the exhaust.

5. 5

   Clean the Port

   Inspect the mounting port on the exhaust pipe. Use a scraper or wire brush to carefully clean away any crystallized DEF or carbon buildup. Do not let debris fall into the exhaust stream.

6. 6

   Install New Valve

   Install the new SCR dosing valve using a new OEM gasket or clamp. Never reuse the old gasket. Torque the mounting hardware to OEM specifications.

7. 7

   Reconnect

   Reattach the coolant lines, the DEF supply line, and the electrical connector.

8. 8

   Refill and Bleed

   Refill the engine coolant. Crucial step: You must bleed the cooling system to ensure there are no air pockets in the lines leading to the new DEF injector, or the new unit will overheat and trigger the code again.

9. 9

   Clear Codes

   Use a diagnostic tool (such as the CNH Electronic Service Tool - EST) to clear the ENG 3545 fault code. Run a forced DEF doser system test to verify the spray pattern, check for leaks, and ensure the torque derate is lifted.