P20B2

DTC P20B2 Diesel Exhaust Fluid (DEF) Heater Valve Performance

Description

The DEF control module controls the heater valve relay which supplies voltage to the DEF heater valve based on temperature signal inputs. The DEF heater valve opens internal valve and circulates the engine coolant to the DEF tank and the DEF supply pump under the specified temperature levels in order to defrost the DEF and keep it warm. If the DEF control module detects that the DEF temperature in the tank does not increase within a predetermined time during the DEF heater valve commanded ON, this DTC will set.

Condition for Running the DTC

- DTCs P205B, P205C, P205D, P20B1, P20B3, P20B4 and U0100 are not set.
- DTCs P0116, P0117, P0118 and P111E are not set in the ECM. (3.0L 4JJ1)
- The battery voltage is between 10 to 16 volts.
- The ignition switch is ON.
- The engine coolant temperature is more than 28 °F (-2 °C). (3.0L 4JJ1)
- The DEF temperature in the tank is less than 23 °F (-5 °C).

Condition for Setting the DTC

- The DEF control module detects that the DEF temperature in the tank does not rise within a predetermined time while the DEF heater valve is commanded ON.

Action Taken When the DTC Sets
- The DEF control module requests the ECM to illuminate the MIL on the second consecutive driving cycle. Refer to DTC Type Definitions for Action Taken When the DTC Sets - Type B.
- 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.

- A sticking DEF heater valve at the closed position will cause this DTC to set.
- A skewed or slow DEF tank temperature sensor may set this DTC. Use the Temperature vs. Resistance table to test the DEF tank temperature sensor at various temperature levels to evaluate the possible of a skewed sensor.

Circuit / System Testing DTC P20B2