System and method for diesel exhaust fluid injector cleaning

A vehicle method, comprising:

• setting a diagnostic code stored in non-transitory memory indicating a degraded DEF injector;
• receiving a request from external a vehicle or internal to the vehicle to operate in a DEF injector cleaning mode;
• and
• responsive to receiving the request and the diagnostic code being cleared, performing the DEF injector cleaning mode, including operating an engine at a cleaning idle speed that is greater than an engine idle speed outside the cleaning mode.

A vehicle system, comprising:

• an engine configured to combust a mixture of diesel fuel and air within a plurality of cylinders;
• an intake throttle valve coupled to an intake passage of the engine;
• an emission control device coupled to an exhaust passage of the engine, including a selective catalytic reduction (SCR) catalyst, a nitrogen oxide sensor, and a diesel particulate filter;
• a diesel exhaust fluid (DEF) delivery system, including a DEF tank holding DEF, a DEF pump for supplying the DEF from the DEF tank to a DEF injector via a DEF line, a pressure sensor coupled to the DEF line, and a temperature sensor coupled to the DEF tank;
• a turbocharger, including a variable geometry turbine (VGT) coupled to the exhaust passage upstream of the emission control device and a compressor coupled to an intake manifold of the engine;
• a temperature sensor coupled to the exhaust passage;
• and
• a controller storing instructions in non-transitory memory that, when executed, cause the controller to:
• operate in a first mode to deliver the DEF to the exhaust passage upstream of the SCR catalyst in response to at least one of an amount of ammonia stored in the SCR catalyst being less than a threshold amount, a speed of the engine being greater than a threshold speed, and a concentration of nitrogen oxides being greater than a threshold concentration;
• and
• operate in a second mode in response to at least one of a diagnostic code stored in non-transitory memory indicating a degraded DEF injector and receiving a request to operate in the second mode from external a vehicle.