40109-ZV5-000 Honda GROMMET, CASE (LOWER) (E) (Honda Code 3704426).

Illustration 1 g03222281
Diesel Exhaust Fluid (DEF) dosing control cabinet components
Valves are shown in a static state
(1) Dosing control cabinet
(2) DEF line to injector at CEM
(3) Air line to injector at CEM
(4) Compressed air source (customer supplied)
(5) DEF source (customer supplied)
(6) DEF pressure sensor
(7) Air assist pressure sensor
(8) Air pressure regulator
(9) Air assist valve (solenoid)
(10) DEF buffer tank return valve (solenoid)
(11) DEF buffer tank return valve (pneumatic)
(12) DEF buffer tank fill valve (solenoid)
(13) DEF buffer tank fill valve (pneumatic)
(14) DEF level sensor
(15) DEF buffer tank
(16) DEF pump The following table is for components located in the dosing control cabinet.
Table 1
Solenoid Valves Pneumatic Valves
System State DEF Buffer
Tank Fill Air Assist DEF Buffer
Tank Return DEF Buffer
Tank Return DEF Buffer Tank Fill
Dormant (sleep mode) Closed(1)
Static state Closed
Static state Open
Static state Open
Static state Closed
Static state
Protect mode against cold (defreeze) Closed Closed Open Open Closed
Preparing dosing readiness
Step 1 Closed Open Open Closed Closed
Preparing dosing readiness
Step 2 Closed Open Closed Open Closed
Preparing dosing readiness
Step 3 Closed Closed Closed Open Closed
Preparing dosing readiness
Step 4 Closed Open Open Closed Closed
Normal dosing operation Open(1) Open Open Closed Open(1)
Dormant (sleep mode) Open(1) Closed Open Closed Open(1)
Shutoff ( wait for after-run) Closed Open Closed Open Closed
(1) Fill valve open when filling is requiredFor the information contained in Troubleshooting, "Warning Operation", observe the following definitions.Open - Flow of air or flow of DEFClosed - No flow of air or no flow DEFDormant Sleep Mode
The SCR dosing system is waiting for engine or aftertreatment conditions to be met. The SCR dosing system will enter dormant sleep mode when any of the following are true:
The engine is not running.
Not all aftertreatment electronics are ready.
The SCR system ECM is not requesting DEF flow.While in this mode the DEF buffer tank automatic filling is enabled. The tank will fill if the level sensor indicates a fill is necessary to maintain a sufficient DEF level.Protect Mode Against Cold (defreeze)
The system will enter protect mode against cold for either of the following:
DEF manifold temperature drops below −5° C (23° F)
DEF tank temperature drops below −10° C (14° F)Temperature sensors are monitored to indicate if there is a freeze potential for the DEF. Heaters are utilized to prevent the freezing of DEF.While in this mode the DEF buffer tank automatic filling is disabled.Upon completion of the protect mode against cold, the process will continue on to preparing dosing readiness.DEF Heating System
The DEF heating system uses a combination of temperature sensors and heaters to prevent damage to components due to DEF freezing. The heaters also keep the SCR dosing system operational. Some heaters are sized to thaw DEF. Some heaters are sized to prevent freezing. When powered, the system will maintain DEF temperature to a minimum of −5° C (23° F). Freezing will be prevented down to −40° C (−40° F). Component heaters can use external power or generator power during genset operation. To prevent DEF from freezing when the system is powered down, the customer is required to drain the DEF tank. The rest of the system is designed to withstand frozen DEF without a mechanical failure.The following are monitored by temperature sensors:
DEF tank temperature
DEF manifold temperature
Dosing control cabinet temperatureThe following DEF system components are heated:
DEF tank
DEF pump
DEF manifold
DEF linesDEF Tank
The DEF tank heater is powered by 120 VAC. This power can come from an external source or be powered by the package during generator operation. This supply is switched with a relay that is controlled by the SCR system ECM.The SCR system ECM uses the DEF tank temperature sensor to control this heater. The heater will be powered when the temperature falls below −5° C (23° F) and will turn off when the temperature rises above 5° C (41° F). Cat ET reports this temperature as " Aftertreatment #1 Catalyst Tank Temperature" and reports the relay status as " Aftertreatment #1 Catalyst Tank Heater".This heater is designed to prevent freezing of the DEF.Power must be provided to the heaters when the engine is shut down, and there is a freeze potential. If power is not provided, the DEF tank must be drained. DEF Pump
The DEF pump heater is powered by 24 VDC that is sourced directly from the SCR system ECM.The SCR system ECM uses the dosing control cabinet temperature sensor to control this heater. The heater will be powered when the temperature falls below −5° C (23° F) and will turn off when the temperature rises above 5° C (41° F). Cat ET reports this temperature as " Aftertreatment #1 Catalyst Tank Temperature" and reports the heater status as " Aftertreatment #1 Catalyst Pump Heater".The DEF pump does not require draining when there is a freeze potential.DEF is allowed to freeze in the pump. The heater can thaw frozen DEF within 70 minutes of engine startup.DEF Manifold
The DEF manifold heater is powered by 24 VDC that is sourced from the batteries to the dosing control cabinet via the engine interface harness. This supply is switched with a relay that is controlled by the SCR system ECM.The SCR system ECM uses the DEF manifold temperature sensor to control this heater. The heater will be powered when the temperature falls below 5° C (41° F) and will turn off when the temperature rises above 30° C (86° F). Cat ET reports this temperature as " Aftertreatment #1 SCR Actual Dosing DEF Temperature" and reports the relay status as " Aftertreatment #1 SCR Catalyst Reagent Manifold Relay Status".The DEF manifold does not require draining when there is a freeze potential.DEF is allowed to freeze in the manifold. The heater can thaw frozen DEF within 70 minutes of engine startup.