P0116

DTC P0116: Engine Coolant Temperature Circuit Range/Performance Problem

Engine Coolant Temperature Sensor Circuit (Part 1):

Engine Coolant Temperature Sensor Circuit (Part 2):

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 7 °C (45 °F) or more when the engine started.

Judgement Criterion
- Engine coolant temperature fluctuates within 1 °C (1.8 °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. Mass airflow sensor output is 13 g/sec or less.
3. During fuel shut-off operation.

OBD-II DRIVE CYCLE PATTERN
Refer to MFI Diagnostic Function-OBD-II Drive Cycle-Pattern 9. OBD-II Drive Cycle

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. Refer to General (Body and Chassis), How to Use Troubleshooting/Inspection Service Points-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" 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 N.m (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 MFI Diagnostic Function-OBD-II Drive Cycle-Pattern 9. OBD-II Drive Cycle
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 Diagnosis-ID Codes Registration Judgment Table [Vehicles with KOS] or Diagnosis-ID Codes Registration Judgment Table [Vehicles with WCM].

NO : It can be assumed that this malfunction is intermittent. Refer to General (Body and Chassis), How to Use Troubleshooting/Inspection Service Points How to Cope with Intermittent Malfunctions.