(d) Reconnect the mass air flow meter sub-assembly connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
OK -- REPLACE ECM See: Powertrain Management/Computers and Control Systems/Engine Control Module/Service and
Repair/Removal
Up to 08/2009
2GR-FE ENGINE CONTROL: SFI SYSTEM: P0115,P0117,P0118: Engine Coolant Temperature Circuit Malfunction
DESCRIPTION
A thermistor, whose resistance value varies according to the engine coolant temperature, is built into the engine coolant temperature sensor.
The structure of the sensor and its connection to the ECM are similar to those of the intake air temperature sensor.
HINT
When any of DTCs P0115, P0117 or P0118 are set, the ECM enters fail-safe mode. During fail-safe mode, the engine coolant
temperature is estimated to be 80锟斤拷C (176锟斤拷F) by the ECM. Fail-safe mode continues until a pass condition is detected.
HINT
When any of these DTCs are set, check the engine coolant temperature by entering the following menus on the Techstream:
Powertrain / Engine / Data List / Coolant Temp.
MONITOR DESCRIPTION
- The engine coolant temperature sensor is used to monitor the engine coolant temperature. The engine coolant temperature sensor has a
thermistor with a resistance that varies according to the temperature of the engine coolant. When the coolant temperature becomes low, the
resistance in the thermistor increases. When the temperature becomes high, the resistance drops. These variations in resistance are reflected in
the output voltage from the sensor. The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature.
When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a malfunction in the engine coolant
temperature sensor and sets a DTC.
- Example:
- If the sensor output voltage is more than 4.91 V for 0.5 seconds or more, the ECM determines that there is an open in the engine coolant
temperature sensor circuit, and sets DTC P0118. Conversely, if the voltage output is less than 0.14 V for 0.5 seconds or more, the ECM
determines that there is a short in the sensor circuit, and sets DTC P0117.
- If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.
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