DTC B1530:87 [HEAT PUMP CONTROL UNIT]

id0702l5719600

Outline

System malfunction location

Heat pump control unit (internal malfunction)

Detection condition

•  The microcomputer in the heat pump control unit detects a communication error with the electric expansion valve drive IC

Fail-safe

•  Stops electric expansion valve operation

Possible cause

•  Heat pump control unit (internal malfunction)

System malfunction location	Heat pump control unit (internal malfunction)
Detection condition	• The microcomputer in the heat pump control unit detects a communication error with the electric expansion valve drive IC
Fail-safe	• Stops electric expansion valve operation
Possible cause	• Heat pump control unit (internal malfunction)

Diagnostic Procedure

Step

Inspection

Results

Action

1

INSPECT HEAT PUMP CONTROL UNIT FOR MALFUNCTION DEPENDING ON REPEATABILITY

•  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

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	INSPECT HEAT PUMP CONTROL UNIT FOR MALFUNCTION DEPENDING ON REPEATABILITY • 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].)
1		No	Go to the next step.
Repair completion verification	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		No	DTC troubleshooting completed.