P208C

DTC P208C Diesel Exhaust Fluid (DEF) Pump Control Circuit Low Voltage

Circuit 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 a short to ground on the pump motor control circuit, this DTC will set.

Condition for Running the DTC

- The battery voltage is between 10 to 16 volts.
- The ignition switch is ON.

Condition for Setting the DTC

- The DEF control module detects a short to ground on the pump motor control circuit for 8 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

- If an intermittent condition is suspected, refer to Intermittent Conditions in this section.

Test Description

The number below refers to the step number on the Circuit/ System Testing.
3. If the DEF pump motor control circuit is normal, open circuit DTC P208A will set.

Circuit / System Testing DTC P208C