Inspection Procedure

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 and the radiator are cold.

HINT:

The detection of this DTC may indicate that the coolant heat storage (CHS) tank outlet water temperature sensor stuck or the water valve stuck.
If DTC P1121 is detected, coolant passages may be clogged.
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. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P1150)

Connect the intelligent tester to the DLC3.
Turn the power switch ON (IG).
Turn the tester ON.
Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

Read DTCs.

Result

RESULT REFERENCE

Display (DTC Output)	Proceed to
P1150	A
P1150 and other DTCs	B

HINT:

If any other codes besides P1150 are output, perform troubleshooting for those DTCs first.

B: Go to DTC CHART

A: Go to Next Step

PERFORM ACTIVE TEST BY INTELLIGENT TESTER

Connect the intelligent tester to the DLC3.
Turn the power switch ON (IG).
Turn the tester ON.
Put the engine in inspection mode (see SFI SYSTEM ).
Start the engine and warm it up.
Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / WATER FLW VLV3, WATER FLW VLV4 or WATER FLW VLV5.

Measure the voltage between terminals WBAD and E2 of the ECM connector.

Fig 1: Identifying E4 And E7 ECM Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION

Tester Operation	Specified Condition
"WATER FLW VLV 3" ON	Approximately 2.5 V
"WATER FLW VLV 4" ON	Approximately 3.5 V
"WATER FLW VLV 5" ON	Approximately 4.5 V

NG: REPLACE WATER W/BRACKET VALVE ASSEMBLY

OK: Go to Next Step

INSPECT TEMPERATURE SENSOR

Remove the CHS tank outlet temperature sensor.

Measure the resistance between the terminals.

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
1 - 2	2 to 3 kΩ at 20°C (68°F)
1 - 2	0.2 to 0.4 kΩ at 80°C (176°F)

NOTE: In case of checking the CHS tank outlet temperature sensor in the water, be careful not to allow water to contact the terminals. After checking, dry the sensor.

HINT:

Alternate procedure: Connect an ohmmeter to the installed CHS tank outlet temperature sensor and read the resistance. Use an infrared thermometer to measure the CHS tank outlet temperature in the immediate vicinity of the sensor. Compare these values to the resistance/ temperature graph. Change the engine temperature (warm up or allow to cool down) and repeat the test.

Reinstall the CHS tank outlet temperature sensor.

NG: REPLACE TEMPERATURE SENSOR

Fig 2: Temperature Sensor Graph

OK: CHECK COOLING SYSTEM (CHECK FOR CLOGGING IN THE COOLING SYSTEM)