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B2444-15 Heater Core Inlet Water Temp Sensor Open/Supply Fault
 
 
cautionBefore replacing the ECU, ensure that the CAN bus lines is normal.
 
 
TROUBLE JUDGMENT
Check Condition
  • The power supply mode of the electric motor switch is ON (READY indicator: ON) or the drive battery is being charged.
Judgment Criterion
  • The high input of the heater core inlet temperature sensor signal is detected for 4 seconds or more.
 
 
PROBABLE CAUSES
  • Malfunction of harness and connectors
  • Malfunction of heater core inlet temperature sensor
  • Malfunction of PHEV A/C amp.
 
 
DIAGNOSIS PROCEDURE
1.Voltage measurement at heater core inlet temperature sensor connector (terminal No.1)
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Change the power supply mode of the electric motor switch to ON (READY indicator: ON).
(3) Measure the voltage between the heater core inlet temperature sensor connector (terminal No.1) and body ground.
OK : About 5 V
Is the inspection result normal?
 
2.Check of open circuit in T_H_C line between PHEV A/C amp. and heater core inlet temperature sensor
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Check the continuity between the PHEV A/C amp. connector (T_H_C terminal) and heater core inlet temperature sensor.
OK : Continuity exists (2 Ω or less)
Is the inspection result normal?
Repair harness or connector.
 
3.Voltage measurement at PHEV A/C amp. connector (T_H_C terminal)
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Change the power supply mode of the electric motor switch to ON (READY indicator: ON).
(3) Measure the voltage between the PHEV A/C amp. connector (T_H_C terminal) and body ground.
OK : 1 V or less
Is the inspection result normal?
Repair harness or connector.
 
4.Check of open circuit between heater core inlet temperature sensor connector (terminal No.2) and body ground.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Check the continuity between the heater core inlet temperature sensor connector (terminal No.2) and body ground.
OK : Continuity exists (2 Ω or less)
Is the inspection result normal?
 
5.Check of open circuit in SG line between PHEV A/C amp. and heater core inlet temperature sensor
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Check the continuity between the PHEV A/C amp. connector (SG terminal) and heater core inlet temperature sensorr.
OK : Continuity exists (2 Ω or less)
Is the inspection result normal?
Repair harness or connector.
 
6.Check the heater core inlet temperature sensor
Check the heater core inlet temperature sensor. Refer to HEATER CORE INLET TEMPERATURE SENSOR INSPECTION.
Is the inspection result normal?
Replace heater core inlet temperature sensor. Refer to HEATER CORE INLET TEMPERATURE SENSOR INSPECTION.
 
7.Check whether the DTC is set again.
(1) Erase the set DTC.
(2) Change the power supply mode of the electric motor switch to OFF.
(3) Wait for 2 minutes or more in key lock condition. (Check that the P indicator on the selector lever turns off.)
(4) Change the power supply mode of the electric motor switch to ON (READY indicator: ON).
(5) Check whether the DTC is set again.
Is the DTC set?
Replace PHEV A/C amp. Refer to Removal and Installation.
The trouble can be an intermittent malfunction. Refer to General Information - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS.