DTC B1531:13 [HEAT PUMP CONTROL UNIT]

id0702l5719700

Outline

System malfunction location	Electric expansion valve circuit malfunction
Detection condition	•  The heat pump control unit detects an open circuit in the electric expansion valve circuit.
Fail-safe	•  Stops electric expansion valve operation
Possible cause	•  Electric expansion valve connector or terminal malfunction •  Heat pump control unit connector or terminal malfunction •  Open circuit in electric expansion valve power supply circuit •  Electric expansion valve malfunction •  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 ELECTRIC EXPANSION VALVE 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.
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 ELECTRIC EXPANSION VALVE POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT •  Inspect the applicable circuit for 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.
5	INSPECT ELECTRIC EXPANSION VALVE FOR MALFUNCTION •  Inspect the applicable part. (See ELECTRIC EXPANSION VALVE 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 HEAT PUMP VALVE COMPONENT No.1 REMOVAL/INSTALLATION.)
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.