Reductant Pump
Draws reductant from the tank and holds the delivery line at several bar so the injector's opening time translates into a known dose. Metering accuracy depends entirely on that pressure being where the module believes it is — a pump that under-delivers makes every dose smaller than commanded, so the system under-doses while reporting that it is doing the right thing.
Its characteristic enemy is the fluid it pumps. Reductant dries into hard crystalline deposits, which jam the pump and block its filter; in cold weather the same fluid freezes at about −11°C and cannot be moved at all. A pump fault in winter is far more often a heater fault, so check the heating circuits before condemning the pump.
It is also responsible for the noise owners ask about. Most systems run the pump after the engine stops, purging fluid back to the tank so the lines are empty and cannot burst if they freeze. A pump audible for a minute or two after switching off is that working correctly — and a system that has stopped doing it is one that will fail at the first hard frost.
Also known as: adblue pump, def pump, urea pump, reductant supply pump, scr pump, dosing pump
Referenced by 51 codes
Codes involving this component (51)
- P208B Reductant Pump A Control Performance/Stuck Off High
- P208E Reductant Injection Valve Stuck Closed Bank 1 Unit 1 High
- P20E8 Reductant Pressure Too Low High
- P20E9 Reductant Pressure Too High High
- P20FB Reductant Pump B Control Performance/Stuck Off High
- P218F Reductant No Flow Detected High
- P05EE Reductant Pump Supply Voltage Circuit/Open
- P05EF Reductant Pump Supply Voltage Circuit Low
- P05F0 Reductant Pump Supply Voltage Circuit High
- P05F1 Reductant Pump Supply Voltage Circuit Stuck On
- P05F2 Reductant Pump Supply Voltage Circuit Stuck Off
- P05F3 Exhaust Aftertreatment Power Relay Control Circuit/Open
- P05F4 Exhaust Aftertreatment Power Relay Control Circuit Low
- P05F5 Exhaust Aftertreatment Power Relay Control Circuit High
- P05F6 Exhaust Aftertreatment Power Relay Control Circuit Stuck On
- P201A Reductant Injection Valve Circuit Range/Performance Bank 2 Unit 1
- P201F Reductant Pump A Stuck On
- P202D Reductant Leakage
- P202E Reductant Injection Valve Circuit Range/Performance Bank 1 Unit 1
- P202F Reductant/Regeneration Supply Control Circuit Range/Performance
- P204A Reductant Pressure Sensor Circuit
- P204B Reductant Pressure Sensor Circuit Range/Performance
- P204C Reductant Pressure Sensor Circuit Low
- P204D Reductant Pressure Sensor Circuit High
- P204E Reductant Pressure Sensor Circuit Intermittent/Erratic
Other components in Exhaust and Emissions
- Oxygen Sensor 326
- EGR Valve 150
- Catalytic Converter 142
- NOx Sensor 118
- Reductant Injector 107
- Exhaust Gas Temperature Sensor 95
- Reductant Tank 95
- Diesel Particulate Filter 76
- SCR Catalyst 65
- EGR Cooler 62
- Exhaust Gas Differential Pressure Sensor 58
- Fuel Tank Pressure Sensor 58
- Exhaust Pressure Control Valve 56
- Reductant Heater 55
- EVAP Vent Valve 43
- Exhaust Aftertreatment Fuel Injector 42
- Charcoal Canister 33
- EGR Position Sensor 32
- Secondary Air Injection Pump 32
- Reductant Temperature Sensor 29
- EVAP Leak Detection Pump 29
- EVAP Purge Valve 27
- Particulate Matter Sensor 24
- Reductant Control Module 24
- Reductant Level Sensor 23
- Secondary Air Switching Valve 22
- EGR Temperature Sensor 21
- Secondary Air Check Valve 21
- Catalyst Heater 20
- Catalyst Temperature Sensor 20
- Fuel Filler Cap 18
- EGR Cooler Bypass Valve 16
- Reductant Quality Sensor 16
- Exhaust Back Pressure Sensor 15
- Purge Flow Sensor 13
- Direct Ozone Reduction Catalyst 13
- EGR Vacuum Solenoid 9
- Fuel Vapour Temperature Sensor 5
- Fuel Additive Control Module 4
- Fuel Additive Tank 4
Information, not instruction
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