Pinpoint Test B: DTC P0A94:4B

High-Voltage Converter/Inverter

Pinpoint Test B: DTC P0A94:4B

Refer to Wiring Diagram Set 12, Charging System for schematic and connector information. [1][2]Diagrams By Number

Normal Operation

The DC to DC Converter Control Module (DC/DC) provides power for the low-voltage vehicle systems and charging of the 12-volt battery. The DC/DC (DC to DC Converter Control Module) can receive a High Speed Controller Area Network (HS-CAN) message from the PCM indicating that the Motor Electronics Cooling System (MECS) temperature exceeds 80°C (176°F). Because of this, the DC/DC (DC to DC Converter Control Module) may limit current output to 100 amps (maximum output is normally greater than 100 amps). When either condition is present, DTC P0A94:4B sets and the DC/DC (DC to DC Converter Control Module) will continue limiting current until the over-temperature condition clears. Periodic or constant heavy electrical loads of the 12-volt system may cause the 12-volt battery to become drained. Reduced functionality of 12-volt systems (headlamps, HVAC blower motor, etc.) may also be noticed.

- DTC P0A94:4B (DC/DC (DC to DC Converter Control Module) Performance: Over Temperature)- Sets when the MECS (Motor Electronics Cooling System) temperature exceeds 80°C (176°F) and/or the DC/DC (DC to DC Converter Control Module) is limiting current output to 100 amps.

This pinpoint test is intended to diagnose the following:

- MECS (Motor Electronics Cooling System)

- DC/DC (DC to DC Converter Control Module)

PINPOINT TEST B : DTC P0A94:4B

B1 CARRY OUT SELF-TEST OF THE PCM

- Connect the scan tool.

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: Self Test- PCM.

Is PCM DTC P0A7C:00 reported?

Yes
REFER to Transmission Cooler, A/T to inspect and diagnose the MECS (Motor Electronics Cooling System) cooling loop circuit. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.

No
GO to B2.

B2 CHECK FOR DC/DC (DC to DC Converter Control Module) DTC P0AF7:00

- Enter the following diagnostic mode on the scan tool: Self Test- DC/DC (DC to DC Converter Control Module).

Is DTC P0AF7:00 reported?

Yes
GO to Pinpoint Test C. Pinpoint Test C: DTC P0AF7:00

No
GO to B3.

B3 CLEAR DTCs AND CARRY OUT SELF-TEST OF THE DC/DC (DC to DC Converter Control Module)

- Using the scan tool, clear the DC/DC (DC to DC Converter Control Module) DTCs.

- Enter the following diagnostic mode on the scan tool: Self Test- DC/DC (DC to DC Converter Control Module).

Is DTC P0A94:4B reported?

Yes
INSTALL a new DC/DC (DC to DC Converter Control Module). REPEAT the self-test. TEST the system for normal operation.

No
Concern is not present at this time. CHECK the MECS (Motor Electronics Cooling System) coolant level. CLEAR the DTC. REPEAT the self-test. TEST the system for normal operation.