DTC U3003:16 [HEAT PUMP CONTROL UNIT]

id0702l5719000

Outline

System malfunction location

Heat pump control unit low power supply voltage input

Detection condition

•  Voltage of the heat pump control unit supply circuit lower than the standard is detected.

Fail-safe

Not applicable

Possible cause

•  Lead-acid battery malfunction

•  Heat pump control unit connector or terminal malfunction

•  Short to ground or open circuit in heat pump control unit power supply circuit

•  Heat pump control unit malfunction

System malfunction location	Heat pump control unit low power supply voltage input
Detection condition	• Voltage of the heat pump control unit supply circuit lower than the standard is detected.
Fail-safe	Not applicable
Possible cause	• Lead-acid battery malfunction • Heat pump control unit connector or terminal malfunction • Short to ground or open circuit in heat pump control unit power supply circuit • Heat pump control unit malfunction

Diagnostic Procedure

Step

Inspection

Results

Action

1

VERIFY HEAT PUMP CONTROL UNIT DTCs AGAIN

•  Clear the DTC recorded in the memory.
(See CLEARING DTC.)

•  Perform the DTC inspection for the heat pump control unit.
(See DTC INSPECTION.)

•  Is the same DTC displayed?

Yes

Go to the next step.

No

Go to repair completion verification 2.

2

INSPECT LEAD-ACID BATTERY FOR MALFUNCTION

•  Inspect the applicable part.
(See LEAD-ACID BATTERY INSPECTION.)

•  Is the part normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning location and perform the repair completion verification.

(See LEAD-ACID BATTERY RECHARGING.)

(See LEAD-ACID BATTERY REMOVAL/INSTALLATION.)

3

INSPECT HEAT PUMP CONTROL UNIT CONNECTOR FOR MALFUNCTION

•  Inspect the applicable connector and terminal.
(See CONNECTOR INSPECTION.)

•  Are the connector and terminal normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning location and perform the repair completion verification.

4

INSPECT HEAT PUMP CONTROL UNIT POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT

•  Inspect the applicable circuit for a short to ground and an open circuit.
(See CIRCUIT INSPECTION.)

•  Is the circuit normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning location and perform the repair completion verification.

Repair completion verification 1

VERIFY THAT VEHICLE IS REPAIRED

•  Install/connect the part removed/disconnected during the troubleshooting procedure.

•  Clear the DTC recorded in the memory.
(See CLEARING DTC.)

•  Perform the DTC inspection for the heat pump control unit.
(See DTC INSPECTION.)

•  Is the same DTC displayed?

Yes

Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error.

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [L.H.D. (E)].)

(See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].)

If the CAN communication is normal, perform the diagnosis from Step 1.

•  If the malfunction is not resolved, replace the heat pump control unit, then go to the next step.
(See HEAT PUMP CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)

No

Go to the next step.

Repair completion verification 2

VERIFY IF OTHER DTCs ARE DISPLAYED

•  Perform the DTC inspection.
(See DTC INSPECTION.)

•  Are other DTCs displayed?

Yes

Repair the malfunctioning part according to the applicable DTC troubleshooting.

No

DTC troubleshooting completed.

Step	Inspection	Results	Action
1	VERIFY HEAT PUMP CONTROL UNIT DTCs AGAIN • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Perform the DTC inspection for the heat pump control unit. (See DTC INSPECTION.) • Is the same DTC displayed?	Yes	Go to the next step.
1		No	Go to repair completion verification 2.
2	INSPECT LEAD-ACID BATTERY FOR MALFUNCTION • Inspect the applicable part. (See LEAD-ACID BATTERY INSPECTION.) • Is the part normal?	Yes	Go to the next step.
2		No	Repair or replace the malfunctioning location and perform the repair completion verification. (See LEAD-ACID BATTERY RECHARGING.) (See LEAD-ACID BATTERY REMOVAL/INSTALLATION.)
3	INSPECT HEAT PUMP CONTROL UNIT CONNECTOR FOR MALFUNCTION • Inspect the applicable connector and terminal. (See CONNECTOR INSPECTION.) • Are the connector and terminal normal?	Yes	Go to the next step.
3		No	Repair or replace the malfunctioning location and perform the repair completion verification.
4	INSPECT HEAT PUMP CONTROL UNIT POWER SUPPLY CIRCUIT FOR SHORT TO GROUND AND OPEN CIRCUIT • Inspect the applicable circuit for a short to ground and an open circuit. (See CIRCUIT INSPECTION.) • Is the circuit normal?	Yes	Go to the next step.
4		No	Repair or replace the malfunctioning location and perform the repair completion verification.
Repair completion verification 1	VERIFY THAT VEHICLE IS REPAIRED • Install/connect the part removed/disconnected during the troubleshooting procedure. • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Perform the DTC inspection for the heat pump control unit. (See DTC INSPECTION.) • Is the same DTC displayed?	Yes	Refer to the controller area network (CAN) malfunction diagnosis flow to inspect for a CAN communication error. (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [L.H.D. (E)].) (See CONTROLLER AREA NETWORK (CAN) MALFUNCTION DIAGNOSIS FLOW [R.H.D.].) If the CAN communication is normal, perform the diagnosis from Step 1. • If the malfunction is not resolved, replace the heat pump control unit, then go to the next step. (See HEAT PUMP CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
Repair completion verification 1		No	Go to the next step.
Repair completion verification 2	VERIFY IF OTHER DTCs ARE DISPLAYED • Perform the DTC inspection. (See DTC INSPECTION.) • Are other DTCs displayed?	Yes	Repair the malfunctioning part according to the applicable DTC troubleshooting.
Repair completion verification 2		No	DTC troubleshooting completed.