DC Power Conversion Test

DC Power Conversion Test

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The 14 volt power module, also referred to as the accessory DC power control module, supplies the energy that flows between the high voltage (300V) direct current (DC) and low voltage (14V) DC to charge the 12V battery and power accessories. The 14V power module receives a wake-up signal on a discrete line from the hybrid powertrain controller 2 when the vehicle is On. After a successful initialization, the 14V power module receives an enable command from the hybrid powertrain control module over the serial data circuits to begin power conversion.

Diagnostic Aids

* A poor connection at the B+ terminal of the 14V power module or open 200 Amp Mega-Fuse in the left rear engine compartment, will prevent the 14V power module from powering up and all values in the 14V power module data list will read zero on the scan tool.
* A poor connection on the 14V power module wake-up signal circuit will prevent the 14V power module from powering up and all data values in the 14V power module data list will read zero on the scan tool.

Reference Information
Schematic Reference

Hybrid Controls Schematics Hybrid Controls Schematics
Connector End View Reference

Component Connector End Views Hybrid/EV Battery Pack X1
Description and Operation

Accessory DC Power Control Module Description and Operation Accessory DC Power Control Module Description and Operation
Electrical Information Reference

* Circuit Testing Circuit Testing
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Verification

1. Vehicle OFF, measure and record the battery voltage at the battery terminals. The battery voltage should stabilize between 12.4 and 12.8 V within a few minutes of turning the vehicle OFF.

• If not within the specified range, refer to Battery Inspection/Test Battery Inspection/Test

2. Vehicle ON, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be at least 1 V greater than the voltage measured in step 1 but less than 15 V.

• If not within the specified range, refer to Circuit/System Testing.

Circuit/System Testing

1. Vehicle ON, verify that no K1 14V power module or B18 battery current sensor DTCs are set that would cause a charging system concern.

• If DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. Vehicle OFF, measure the voltage across the battery terminals. The voltage should read 12.4 V or greater at room temperature.

• If not within the specified range, refer to Battery Inspection/Test Battery Inspection/Test

3. Connect a carbon pile tester to the C1 battery.
4. Vehicle ON, turn all accessories off. Observe the voltage reading on the tester. The voltage should read between 12.6-15.5V.
5. Adjust the carbon pile tester so that the 12V current on the 14V power module data list is reading 160 amps. The voltage reading should remain between 12.6-15.5V.

• If not within the specified value, replace the K1 14V power module.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

Control Module References Programming and Relearning for Accessory DC Power Control Module, also called the 14V power module, replacement, programming, and setup.