Volvo

The aftertreatment control module (ACM) uses the aftertreatment diesel exhaust fluid (DEF) dosing pressure sensor value to adjust and maintain DEF pressure at the DEF dosing valve by controlling DEF pump speed. If the pressure decreases below expected value when the pump is in initial pressure build-up mode or if the pressure increases above expected value when pump is in idle speed mode, the ACM considers DEF pressure outside of normal operating range and indicates a malfunction in a DEF dosing pressure sensor. Conditions for diagnostic trouble code (DTC):1) DEF dosing pressure too high based on existing conditions Observable symptoms1)...

The Idle Validation Switch is open at the idle position and transmits no voltage to the (VECU) Vehicle Electronic Control Unit. At approximately 1-13% pedal position the Idle Validation Switch closes and completes the circuit to the (VECU) Vehicle Electronic Control Unit.The (VECU) Vehicle Electronic Control Unit then sends a voltage signal to the Engine Control Module (ECM) indicating accelerator pedal position. If both communication links (J1939, J1587) are faulty the pedal demand functionality enters limp-home. During limp-home the (IVS) Idle Validation Switch is used for ramping requested torque. Conditions for diagnostic trouble code (DTC):1) Accelerator pedal (AP) released2) Short...

The Idle Validation Switch is open at the idle position and transmits no voltage to the (VECU) Vehicle Electronic Control Unit. At approximately 1-13% pedal position the Idle Validation Switch closes and completes the circuit to the (VECU) Vehicle Electronic Control Unit.The (VECU) Vehicle Electronic Control Unit then sends a voltage signal to the Engine Control Module (ECM) indicating accelerator pedal position. If both communication links (J1939, J1587) are faulty the pedal demand functionality enters limp-home. During limp-home the (IVS) Idle Validation Switch is used for ramping requested torque. Conditions for diagnostic trouble code (DTC):1) Accelerator pedal pressed down more...

The preheat Relay controls the preheater from an electric signal from the Engine Control Module (ECM). This function is used to warm up the inlet air during cold conditions. This provides more reliable starting and reduces exhaust emissions during cold starts. Vehicles can be equipped with or without the preheater. Conditions for diagnostic trouble code (DTC):1) Output activated2) Short circuit to battery voltage on A14.EB:25 Observable symptoms1) Intake air heater (IAH) relay never activated2) Difficult to start in extreme cold3) White smoke at cold start Probable cause1) Engine wiring harness2) Connector3) Intake air heater (IAH) relay Volvo All Engines (2010...

The preheat Relay controls the preheater from an electric signal from the Engine Control Module (ECM). This function is used to warm up the inlet air during cold conditions. This provides more reliable starting and reduces exhaust emissions during cold starts. Vehicles can be equipped with or without the preheater. Conditions for diagnostic trouble code (DTC):1) Output activated2) Short circuit to battery voltage on A14.EB:25 Observable symptoms1) Intake air heater (IAH) relay never activated2) Difficult to start in extreme cold3) White smoke at cold start Probable cause1) Engine wiring harness2) Connector3) Intake air heater (IAH) relay Volvo All Engines (2010...