P0116
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 ECM (terminal No. 26) via the resistor in the ECM. The ground terminal (terminal No. 2) is grounded with ECM (terminal No. 27).
- 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 resistance decreases.
- The engine coolant temperature sensor output voltage increases when the resistor increases and decreases when the resistance decreases.
TECHNICAL DESCRIPTION
- The engine coolant temperature sensor converts the engine coolant temperature to a voltage and outputs it.
- The ECM 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)
- Mass airflow sensor
- Intake air temperature sensor
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
- Engine coolant temperature was more than 7°C (45°F) when the engine started.
- The accumulation is more than 300 seconds during the acceleration having the mass airflow rate of 12 g/sec or more.
- The accumulation is more than 30 seconds during the deceleration having the mass airflow rate of 9 g/sec or less.
Judgement Criterion
- Engine coolant temperature fluctuates within 1°C (1.8°F) after 330 seconds 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. During fuel shut-off operation.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 9 Monitors, Trips, Drive Cycles and Readiness Codes.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
- Engine coolant temperature sensor failed.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Using scan tool MB991958, check data list item 6: Engine Coolant Temperature Sensor.
CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Set scan tool MB991958 to the data reading mode for item 6, Engine Coolant Temperature Sensor.
- The engine coolant temperature and temperature shown with the scan tool should approximately match.
(4)Turn
the ignition switch to the "LOCK" (OFF) position.
Q. Is the sensor operating properly?
YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.
NO Go to Step 2.
STEP 2. Check the engine coolant temperature sensor.
(1)Disconnect the engine coolant temperature sensor connector B-09.
(2)Remove the engine coolant temperature sensor.
(3)With the temperature sensing portion of engine coolant temperature sensor immersed in hot water, measure resistance.
Standard value:
14 - 17 kohms [at -20°C (-4°F)]
5.1 - 6.5 kohms [at 0°C (32°F)]
2.1 - 2.7 kohms [at 20°C (68°F)]
0.9 - 1.3 kohms [at 40°C (104°F)]
0.48 - 0.68 kohms [at 60°C (140°F)]
0.26 - 0.36 kohms [at 80°C (176°F)]
(4)Apply 3M(TM) AAD part number 8731 or equivalent on the screw section of the engine coolant temperature sensor.
(5)Install the engine coolant temperature sensor, and tighten to the specified torque.
Tightening torque: 29 ± 10 Nm (22 ± 7 ft-lb)
Q. Is the measured resistance normal?
YES Replace the engine coolant temperature sensor. Then go to Step 3.
NO Go to Step 3.
STEP 3. Test the OBD-II drive cycle.
(1)Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 9 Monitors, Trips, Drive Cycles and Readiness Codes.
(2)Check the diagnostic trouble code (DTC).
Q. Is DTC P0116 set?
YES Replace the ECM. When the ECM is replaced, register the ID code. Refer to ID registration procedure manual - ID codes registration judgement table [Vehicles with KOS] or ID registration procedure manual - ID codes registration judgement table [Vehicles with WCM].
NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.