Test Procedure

HH1 DIAGNOSTIC TROUBLE CODES (DTCS) P0A08, P0A09, P0A10, P0A11, P0A12 AND P0A13: CHECK FOR SELF-TEST DTCS

NOTE: The DTC P0A08 may be set as a result of the concern with the motor electronics cooling system. If DTC P0A7C is present, then diagnose this DTC before diagnosing any other DTCs. After diagnosis of DTC P0A7C is complete, clear all DTCs and carry out the self-test. If DTC P0A08 is retrieved again, continue with this pinpoint test.

NOTE: Repair any DTCs related to the motor electronics coolant temperature (MECT) or contractors before entering this pinpoint test.

NOTE: The 12-volt battery must be sufficiently charged for DC/DC diagnostics.

NOTE: The traction battery (TB) must be at a minimum of 35% state of charge for the PCM to activate the DCE circuit with the KOER position.

Are DTCs P0A08, P0A09, P0A10, P0A11, P0A12, P0A13 present during PCM or transaxle control module (TCM) self-test?

Yes	No
For KOEO and KOER DTCs P0A08, P0A09, P0A10, P0A11, P0A12 and P0A13, GO to HH2. For continuous memory DTCs P0A08, P0A09, P0A10, P0A11, P0A12 and P0A13, GO to HH21.	Unable to duplicate or identify the concern at this time. RETURN to SYMPTOM CHARTS for further direction.

HH2 CHECK IF THE VEHICLE ENGINE STARTS

Does the engine start?

Yes	No
GO to HH5.	GO to HH3.

HH3 CHECK THE HIGH VOLTAGE BATTERY CONTRACTOR STATUS

Ignition ON, engine OFF.
Access the TCM and monitor the CONTACT PID.

Does the PID indicate the contractors are closed?

Yes	No
GO to HH4.	Unable to close the traction battery contractors. REFER to HIGH VOLTAGE TRACTION BATTERY .

HH4 CHECK THE TRANSAXLE ASSEMBLY HIGH VOLTAGE

Access the TCM and monitor the HVBAT_V PID.

Is the voltage between 216 - 400 V?

Yes	No
GO to HH5.	DIAGNOSE the high voltage supply concern. GO to TT8.

HH5 VERIFY THE MOTOR ELECTRONICS COOLANT TEMPERATURE (MECT)

NOTE: High MECT limits DC/DC converter performance.

Access the PCM and monitor the MECT_V PID.

Is the voltage greater than 1.2 V?

Yes	No
GO to HH6.	DIAGNOSE the MECT concern. GO to DN2.

HH6 VERIFY THE 12-VOLT BATTERY CONNECTIONS ON THE DC/DC CONVERTER

Ignition OFF.
Check the 12-volt battery connections on the DC/DC converter for corrosion and the proper connection.
Measure the voltage at the DC/DC converter 12-volt battery connections.

Does the voltage read +/- 0.1 volt of 12-volt battery voltage?

Yes	No
GO to HH7.	REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.

HH7 CHECK THE HIGH VOLTAGE POSITIVE CABLE FOR AN OPEN

Ignition OFF.
Transaxle Assembly-DDHV connector disconnected.
DDC-HV connector disconnected.
Measure the resistance between:

(+) Transaxle Assembly-DDHV Connector, Harness Side	(-) DDC-HV Connector, Harness Side
HVP - Pin (+)	HVP - Pin (+)

Is the resistance less than 5 ohms?

Yes	No
GO to HH8.	INSTALL a new high voltage cable from the transaxle assembly to the DC/DC converter. REFER to HIGH VOLTAGE CONVERTER/INVERTER .

HH8 CHECK THE HIGH VOLTAGE NEGATIVE CABLE FOR AN OPEN

Measure the resistance between:

(+) Transaxle Assembly-DDHV Connector, Harness Side	(-) DDC-HV Connector, Harness Side
HVN - Pin (-)	HVN - Pin (-)

Is the resistance less than 5 ohms?

Yes	No
GO to HH9.	INSTALL a new high voltage cable from the transaxle assembly to the DC/DC converter. REFER to HIGH VOLTAGE CONVERTER/INVERTER .

HH9 CHECK FOR THE DC/DC CONVERTER OVERCHARGING THE 12-VOLT BATTERY

NOTE: Disconnecting the DCE circuit when the ignition is in the ON position will activate the DC/DC converter.

DDC-HV connector connected.
Transaxle Assembly-DDHV connector connected.
Ignition ON, engine OFF.
DDC-A connector disconnected.
Measure the voltage between:

(+) Vehicle Battery	(-) Vehicle Battery
Positive terminal	Negative terminal

Is VBAT less than 16 volts when the DC/DC converter is enabled?

Yes	No
GO to HH10.	INSTALL a new DC/DC converter. REFER to HIGH VOLTAGE TRACTION BATTERY .

HH10 CHECK THE FUNCTIONALITY OF DC/DC CONVERTER

NOTE: Disconnecting the DCE circuit when the ignition is in the ON position will activate the DC/DC converter.

Ignition ON, engine OFF.
DDC-A connector disconnected.

Measure the voltage between:

(+) Vehicle Battery	(-) Vehicle Battery
Positive terminal	Negative terminal

Record the 12 volt battery voltage.
Ignition OFF.
Record the 12 volt battery voltage.

Does the 12-volt battery voltage increase when the ignition is in the ON position?

Yes	No
GO to HH11.	INSTALL a new DC/DC converter. REFER to HIGH VOLTAGE TRACTION BATTERY .

HH11 CHECK THE DCE CIRCUIT FOR AN OPEN IN THE HARNESS

PCM connector disconnected.
Measure the resistance between:

(+) DDC-A Connector, Harness Side	(-) PCM Connector, Harness Side
DCE - Pin 1	DCE - Pin T12

Is the resistance less than 5 ohms?

Yes	No
GO to HH12.	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

HH12 CHECK THE DCE CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

Ignition ON, engine OFF.
Measure the voltage between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
DCE - Pin T12	Negative terminal

Is any voltage present?

Yes	No
GO to HH13.	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

HH13 CHECK THE DCE CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

Ignition OFF.
Measure the resistance between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
DCE - Pin T12	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
GO to HH14.	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

HH14 CHECK THE FUNCTIONALITY OF THE DCE CIRCUIT

Ignition ON, engine OFF.

Connect a 5 amp fused jumper wire between the following:

Point A DDC-A Connector, Component Side	Point B Vehicle Battery
DCE - Pin 1	Negative terminal

Measure the voltage between:

(+) Vehicle Battery	(-) Vehicle Battery
Positive terminal	Negative terminal

Does VBAT drop approximately 1 volt when the jumper wire is installed (forcing the DC/DC to disable), and increase approximately 1 volt when the jumper wire is removed (forcing the DC/DC to enable)?

Yes	No
GO to HH15.	INSTALL a new DC/DC converter. REFER to HIGH VOLTAGE CONVERTER/INVERTER .

HH15 CHECK THE FUNCTIONALITY OF THE PCM DCE CIRCUIT

Ignition OFF.
DDC-A connector connected.
PCM connector connected.

Measure the voltage between:

(+) Vehicle Battery	(-) Vehicle Battery
Positive terminal	Negative terminal

Ignition ON, engine OFF.
Access the PCM and control the DCE PID.
Enable and disable the DCE circuit.

Does VBAT indicate the DC/DC converter is cycling on and off with output state control?

Yes	No
CLEAR the DTCs. GO to HH16.	GO to HH22.

HH16 CHECK THE DCF CIRCUIT FOR AN OPEN CIRCUIT IN THE HARNESS

Ignition OFF.
DDC-A connector disconnected.
PCM connector disconnected.
Measure the resistance between:

(+) DDC-A Connector, Harness Side	(-) PCM Connector, Harness Side
DCF - Pin 6	DCF - Pin B8

Is the resistance less than 5 ohms?

Yes	No
GO to HH17.	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

HH17 CHECK THE DCF CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS

Ignition ON, engine OFF.
Measure the voltage between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
DCF - Pin B8	Negative terminal

Is any voltage present?

Yes	No
GO to HH18.	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

HH18 CHECK THE DCF CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

Ignition OFF.
Measure the resistance between:

(+) PCM Connector, Harness Side	(-) Vehicle Battery
DCF - Pin B8	Negative terminal

Is the resistance greater than 10K ohms?

Yes	No
GO to HH19.	REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

HH19 CHECK THE DCF CIRCUIT FOR AN OPEN IN THE PCM

Ignition OFF.
Measure the resistance between:

(+) PCM Connector, Component Side	(-) PCM Connector, Component Side
VPWR - Pin B67, B68	DCF - Pin B8

Is the resistance between 1K - 2K ohms?

Yes	No
GO to HH20.	GO to HH22.

HH20 CHECK THE DCF CIRCUIT FOR A SHORT TO GND IN THE PCM

PCM connector connected.
Ignition ON, engine OFF.
Measure the voltage between:

(+) DDC-A Connector, Harness Side	(-)
DCF - Pin 6	Ground

Is the voltage less than 10.5 V?

Yes	No
GO to HH22.	INSTALL a new DC/DC converter. REFER to HIGH VOLTAGE TRACTION BATTERY .

HH21 CHECK THE DC TO DC CONVERTER CIRCUITS FOR AN INTERMITTENT CONCERN

NOTE: The continuous memory PCM DTC P0A09 alone indicates the intermittent DC/DC fault (DCF) circuit failure, or the 12 V bus voltage dropped below the calibrated threshold.

Ignition ON, engine OFF.
Access the PCM and monitor the DCE PID.
Access the PCM and monitor the DCE_F PID.
Carefully wiggle all accessible wiring and connectors associated with the circuit and look for a change in the PID state.

Does the PID indicate a concern while wiggling the harness or connectors?

Yes	No
REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.	Unable to duplicate or identify the concern at this time. Make sure the 12-volt battery is sufficiently charged.

HH22 CHECK FOR CORRECT PCM OPERATION

Disconnect all the PCM connectors.
Visually inspect for:
- pushed out pins
- corrosion
Connect all the PCM connectors and make sure they seat correctly.
Carry out the PCM self-test and verify the concern is still present.

Is the concern still present?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.