Inspection Procedure

HINT:

Although each DTC title says "Coolant Flow Control Valve", these DTCs are related to the water valve.

CAUTION: Be careful when replacing any part in the system or changing the coolant because the coolant in the heat storage tank is hot even if the engine is cold.

HINT:

To check the coolant heat storage (CHS) system, the ECM may cause the water pump of the CHS system to operate 5 hours after the power switch has been turned OFF.
Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

CHECK ECM (WBAD - E2 VOLTAGE)

Turn the power switch ON (IG).

Measure voltage between the terminals WBAD and E2 of the E4 and E7 ECM connectors.

Standard voltage

WATER VALVE AND SPECIFIED CONDITION

Water Valve	Specified Condition
Valve position "A" (Preheat mode)	Approximately 2.5 V
Valve position "B" (Recovering mode)	Approximately 3.5 V
Valve position "C" (Normal Operation)	Approximately 4.5 V

Fig 1: Measuring Voltage Between Terminals WBAD And E2 Of E4 And E7 ECM Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

After the HV main system is turned OFF (READY to IG OFF condition), the valve position will be set to position A.

OK : CHECK FOR INTERMITTENT PROBLEMS

NG : GO TO NEXT STEP

INSPECT WATER M/BRACKET VALVE ASSEMBLY

Disconnect the W5 water valve connector.
Measure resistance between terminals WSL1 and WSL2 of the water valve connector.

Measure resistance between terminals WSAD and E2 of the water valve connector.

Standard resistance

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specification Condition
1 (WSL1) - 2 (WSL2)	Approximately 0.04 kΩ
5 (WSAD) - 6 (E2)	0.2 to 5.7 kΩ

Fig 2: Disconnecting W5 Water Valve Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG : REPLACE WATER W/BRACKET VALVE ASSEMBLY

OK : GO TO NEXT STEP

CHECK HARNESS AND CONNECTOR (WATER VALVE - ECM)

Disconnect the W5 water valve connector.

Fig 3: Identifying W5 Water Valve Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Disconnect the E4 and E7 ECM connectors.

Measure the resistance between the wire harness side connectors.

Standard resistance (Check for open)

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
W5-5 (Water valve) - E7-20 (WBAD)	Below 1 Ω
W5-4 (Water valve) - E4-18 (VC)	Below 1 Ω
W5-6 (Water valve) - E4-28 (E2)	Below 1 Ω

Fig 4: Disconnecting E4 And E7 ECM Connectors

Standard resistance (Check for short)

TESTER CONNECTION AND SPECIFIED CONDITION

Tester Connection	Specified Condition
W5-5 (Water valve) or E7-20 (WBAD) - Body ground	10 kΩ or higher

Reconnect the water valve connector.
Reconnect the ECM connectors.

NG : REPAIR OR REPLACE HARNESS AND CONNECTOR

OK : REPLACE ECM