P208A
DTC P208A Diesel Exhaust Fluid (DEF) Pump Control CircuitCircuit Description
The DEF is drawn in from the DEF tank to the supply pump by operating an internal diaphragm type pump driven with the pump motor and it is sent to the DEF injector via the main filter and the pressure line. The DEF pressure is kept near constant pressure by controlling speed of the pump motor. The pump motor has the following circuits.
- Power supply circuit
- Low reference circuit
- Control circuit
The power supply circuit provides a battery voltage to the pump motor from the control module internal high side driver circuit, and the pump motor speed is controlled through the control circuit by pulling the internal low side driver circuit to the ground with pulse width modulation (PWM) signal. If the DEF control module detects an open circuit on the pump motor control circuit, this DTC will set.
Condition for Running the DTC
- The battery voltage is between 10 and 16 volts.
- The ignition switch is ON.
Condition for Setting the DTC
- The DEF control module detects an open circuit on the pump motor control circuit for 3 seconds.
Action Taken When the DTC Sets
- The DEF control module requests the ECM to illuminate the MIL. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type A.
- The DEF control module and the ECM apply defaulted warning actions and fail-safe controls. Refer to Default Action and Fail-Safe List.
Conditions for Clearing the DTC
- Refer to DTC Type Definitions for Conditions for Clearing the DTC - Type A or Type B.
Diagnostic Aids
Caution: Diesel Exhaust Fluid (DEF) is highly corrosive to electrical connectors and rubber used in electrical wiring. If any of these components come in contact with DEF, wash the area throughly with warm water and allow to completely dry before reconnection. Make a visual inspection for damage if the connection has been exposed to DEF.
- If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Circuit / System Testing DTC P208A
