DTC P0116: Engine Coolant Temperature Circuit Range/Performance Problem

CIRCUIT OPERATION
• 5-volt voltage is applied to the engine coolant temperature sensor output terminal (terminal No. 1) from the PCM (terminal No. 44) via the resistor in the PCM. The ground terminal (terminal No. 2) is grounded with PCM (terminal No. 57).
• The engine coolant temperature sensor is a negative temperature coefficient type of resistor. It has the characteristic that when the engine coolant temperature rises the resistor decreases.
• The engine coolant temperature sensor output voltage increases when the resistor increases and decreases when the resistor decreases.
TECHNICAL DESCRIPTION
• The engine coolant temperature sensor converts the engine coolant temperature to a voltage and output it.
• The PCM checks whether this voltage is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
Engine coolant temperature sensor output voltage does not change for specified period when engine coolant temperature sensor output voltage at engine start is over 7°C (45°F).
MONITOR EXECUTION
Once per driving cycle
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
• Not applicable

Sensor (The sensor below is determined to be normal)
• Volume airflow sensor
• Engine coolant temperature sensor
• Intake air temperature sensor
DTC SET CONDITIONS Logic Flow Chart


Check Conditions
Engine coolant temperature was 7°C (45°F) or more immediately before the engine was stopped at the last drive.
Engine coolant temperature was 7°C (45°F) or more when the engine started.

Judgement Criteria
• Engine coolant temperature fluctuates within 1°C (34°F) after 5 minutes have passed since the engine was started.
• However, time is not counted if any of the following conditions are met.
(1)Intake air temperature is 60°C (140°F) or more.
(2)Volume airflow sensor output frequency is 70 Hz or less.
(3)During fuel shut-off operation.

• The PCM monitors for this condition once during the drive cycle.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function-OBD-II Drive Cycle-Procedure 6-Other Monitor .
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:
• Engine coolant temperature sensor failed.
• Harness damage in engine coolant temperature sensor circuit, or connector damage.
• PCM failed.