P1115

1NZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P1115: Coolant Temperature Sensor Circuit for Coolant Heat Storage System

DTC P1115 - Coolant Temperature Sensor Circuit for Coolant Heat Storage System

DTC P1117 - Coolant Temperature Sensor Circuit Low for Coolant Heat Storage

DTC P1118 - Coolant Temperature Sensor Circuit High for Coolant Heat Storage

DESCRIPTION
HINT: Although each DTC title says "Coolant Temperature Sensor", these DTCs are related to the coolant heat storage tank outlet temperature sensor.





This system uses an electric pump to supply hot coolant stored in the coolant heat storage tank into the cylinder head of the engine, in order to optimize engine starting combustion and reduce the amount of unburned gas that is discharged while the engine is started. Before the engine starts, the ECM operates the electric water pump to direct the hot coolant in the heat storage tank into the engine, in order to heat the cylinder head (this process is called "preheat mode"). The duration of the operation of the electric water pump is variable, depending on the temperature of the cylinder head. During the normal operation of the engine, the water valve opens the passage between the cylinder head and the heater and closes the passage between the cylinder head and the tank. During preheat mode in which the cylinder head is heated, the water valve opens the passage between the tank and the cylinder head, in order to allow the coolant to flow from the tank to the cylinder head. At this time, in order to warm up the intake port quickly before the engine is started, the coolant flows in the reverse direction.
The sensor for the system, which is provided at the tank outlet, is constructed similarly to the engine coolant temperature sensor and is connected to the ECM. The CHS tank outlet temperature sensor has a built in thermistor, whose resistance varies with the coolant temperature.
HINT: If the ECM detects DTC P0115, P0117 or P0118, it operates the fail-safe function in which the engine coolant temperature is assumed to be 80°C (176°F).





MONITOR DESCRIPTION

The ECM monitors the sensor voltage and uses this value to control the coolant heat storage (CHS) system properly. If the sensor output voltage deviates from the normal operating range, the ECM determines that the CHS tank outlet temperature sensor circuit has malfunctioned, and outputs a DTC.
Example:
A sensor output voltage of -40°C (-40°F) or 140°C (284°F) is determined as a malfunction.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P1115:





P1117:





P1118:





COMPONENT OPERATING RANGE





WIRING DIAGRAM





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 is cold.
HINT:
- If different DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
- 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 Techstream. 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.

PROCEDURE

1. READ VALUE USING TECHSTREAM
(a) Connect Techstream to the DLC3.
(b) Turn the power switch ON (IG) and turn Techstream ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Code.
(d) Read the DTCs.
Result:






B -- CHECK HARNESS AND CONNECTOR (CHS TANK OUTLET TEMPERATURE SENSOR - ECM)
A -- Continue to next step.

2. CHECK ECM (THW2 - E2 VOLTAGE)




(a) Turn the power switch ON (IG).
(b) Measure the voltage between terminals THW2 and E2 of the ECM E4 and E7 connectors.
Standard voltage:






OK -- CHECK FOR INTERMITTENT PROBLEMS
NG -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (CHS TANK OUTLET TEMPERATURE SENSOR - ECM)
(a) Check the harness and the connectors between the coolant heat storage tank outlet temperature sensor and the ECM connectors.





(1) Disconnect the C19 CHS tank outlet temperature sensor connector.





(2) Disconnect the E4 and E7 ECM connectors.
(3) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):






Standard resistance (Check for short):






(4) Reconnect the CHS tank outlet temperature sensor connector.
(5) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. INSPECT OIL TEMPERATURE SENSOR (CHS TANK OUTLET TEMPERATURE SENSOR)




(a) Remove the coolant heat storage (CHS) tank outlet temperature sensor.
(b) Measure the resistance between the terminals.
Standard resistance:





NOTE: In case of checking the CHS tank outlet temperature sensor in water, be careful not to allow water to contact the terminals. After checking, dry the sensor.
HINT: Alternative 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.
(c) Reinstall the coolant heat storage tank outlet temperature sensor.
NG -- REPLACE OIL TEMPERATURE SENSOR
OK -- REPLACE ECM