New Holland DCU 19262 – DCU (Dosing Control Unit): Tank heating Valve | Short circuit to battery

This code indicates that the control module has detected a high voltage short circuit (short to battery) on the electrical circuit that controls the DEF (Diesel Exhaust Fluid) / AdBlue tank heating valve.

• T4
• T5
• T6
• T7
• T8
• T9
• T6.140
• T7.220
• T7.270
• T8.275

1. 1

   Isolate the Short: Disconnect the electrical connector at the DEF tank heating valve. If the active fault code changes from a 'short circuit to battery' (19262 / P20B4) to an 'open circuit' (19264 / P20B1), the wiring harness is fine, and the valve itself is internally shorted and must be replaced.

2. 2

   Harness Inspection: If the code remains 19262 after unplugging the valve, the short to battery voltage is in the wiring harness between the DCU and the valve. Inspect the harness for chafing, melted insulation, or pinched wires.

3. 3

   Connector Check: Inspect the valve's electrical connector for corrosion, water ingress, or damaged pins.

4. 4

   Hose Routing Check: Verify that the DEF heater line with the 'red' band is connected to the top tube running to the front part of the engine head to ensure correct routing and prevent continuous hot water circulation.

1. 1

   Turn off the ignition and disconnect the battery to prevent electrical spikes.

   Turn off the ignition and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the DEF tank heating valve (coolant control valve), which is typically located in the engine compartment inline with the coolant hoses routing to the DEF tank.

   Locate the DEF tank heating valve (coolant control valve), which is typically located in the engine compartment inline with the coolant hoses routing to the DEF tank.

3. 3

   Disconnect the electrical connector from the valve.

   Disconnect the electrical connector from the valve.

4. 4

   To prevent excessive coolant loss, pinch off the coolant lines leading to and from the valve using hose pinch-off pliers. Alternatively, drain the engine coolant below the level of the valve.

   To prevent excessive coolant loss, pinch off the coolant lines leading to and from the valve using hose pinch-off pliers. Alternatively, drain the engine coolant below the level of the valve.

5. 5

   Loosen the hose clamps and remove the coolant hoses from the valve.

   Loosen the hose clamps and remove the coolant hoses from the valve.

6. 6

   Unbolt the defective valve from its mounting bracket and remove it.

   Unbolt the defective valve from its mounting bracket and remove it.

7. 7

   Install the new DEF tank heating valve.

   Install the new DEF tank heating valve.

8. 8

   Reconnect the coolant hoses, ensuring correct routing (e.g., red band to the top tube) and tighten the hose clamps.

   Reconnect the coolant hoses, ensuring correct routing (e.g., red band to the top tube) and tighten the hose clamps.

9. 9

   Reconnect the electrical connector.

   Reconnect the electrical connector.

10. 10

    Remove the hose pinch-off pliers (or refill the engine coolant system and bleed any air pockets).

    Remove the hose pinch-off pliers (or refill the engine coolant system and bleed any air pockets).

11. 11

    Reconnect the battery.

    Reconnect the battery.

12. 12

    Use the CNH Electronic Service Tool (EST) to clear the fault codes and run the engine to verify the repair and check for coolant leaks.

    Use the CNH Electronic Service Tool (EST) to clear the fault codes and run the engine to verify the repair and check for coolant leaks.