DTC U0424:68 [HEAT PUMP CONTROL UNIT]

id0702l5718500

Outline

System malfunction location

Error signal received from dash-electrical supply unit

Detection condition

•  The heat pump control unit receives a CAN error signal from the dash-electrical supply unit.

Fail-safe

•  The value of the error signal is fixed at the specified value.

Possible cause

•  Dash-electrical supply unit stores DTCs

•  Dash-electrical supply unit malfunction

•  Heat pump control unit malfunction

System wiring diagram

Not applicable

Connector diagram

Not applicable

System malfunction location	Error signal received from dash-electrical supply unit
Detection condition	• The heat pump control unit receives a CAN error signal from the dash-electrical supply unit.
Fail-safe	• The value of the error signal is fixed at the specified value.
Possible cause	• Dash-electrical supply unit stores DTCs • Dash-electrical supply unit malfunction • Heat pump control unit malfunction
System wiring diagram	Not applicable
Connector diagram	Not applicable

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 FOR DASH-ELECTRICAL SUPPLY UNIT RELATED MALFUNCTION

•  Perform the DTC inspection for dash-electrical supply unit.
(See DTC INSPECTION.)

•  Is a DTC displayed?

Yes

Repair the malfunctioning part according to the applicable DTC troubleshooting.

(See DTC TABLE [DASH-ELECTRICAL SUPPLY UNIT].)

No

Go to the next step.

3

INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY

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

•  Perform the DTC inspection for the body control module (BCM).
(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 CAN communication is normal, replace the dash-electrical supply unit and perform the repair completion verification procedure.

(See DASH-ELECTRICAL SUPPLY UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)

No

Go to repair completion verification 2.

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 FOR DASH-ELECTRICAL SUPPLY UNIT RELATED MALFUNCTION • Perform the DTC inspection for dash-electrical supply unit. (See DTC INSPECTION.) • Is a DTC displayed?	Yes	Repair the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [DASH-ELECTRICAL SUPPLY UNIT].)
2		No	Go to the next step.
3	INSPECT PCM FOR MALFUNCTION DEPENDING ON REPEATABILITY • Clear the DTC recorded in the memory. (See CLEARING DTC.) • Perform the DTC inspection for the body control module (BCM). (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 CAN communication is normal, replace the dash-electrical supply unit and perform the repair completion verification procedure. (See DASH-ELECTRICAL SUPPLY UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
3		No	Go to repair completion verification 2.
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.