P0116

DTC P0116: Engine Coolant Temperature Circuit Range/Performance Problem

CAUTION:
If DTC P0116 has been set, TCL related DTC U1120 is also set. After P0116 has been diagnosed, don't forget to erase DTC U1120.

CIRCUIT OPERATION

- 5-volt voltage is applied to the engine coolant temperature sensor output terminal (terminal No. 1) from the ECM [M/T] or the PCM [A/T] (terminal No. 93) via the resistor in the ECM [M/T] or the PCM [A/T]. The ground terminal (terminal No. 2) is grounded with ECM [M/T] or PCM [A/T] (terminal No. 69).
- 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 resistance 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 [M/T] or the PCM [A/T] 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
- Engine coolant temperature sensor
- Intake air temperature sensor

DTC SET CONDITIONS

Logic Flow Chart

Check Condition

- Engine coolant temperature was 7°C (45°F) or more when the engine started.
Judgement Criteria

- Engine coolant temperature fluctuates within 1°C (1.8°F) after 330 seconds have passed since the engine was started.
- The accumulated time in the acceleration* is 300 sec or more.
Acceleration*: The air flow rate is 12g/sec or more.
- The accumulated time in the deceleration** is 30 sec or more.
deceleration**: The air flow rate is 9g/sec or less.
- 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.
- Harness damage or connector damage.
- ECM failed.[ M/T]
- PCM failed.[ A/T]

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-106.
(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: 30± 9Nm (22± 7 ft-lb)

Q. Is the measured resistance at the standard value?

YES Go to Step 3.

NO Replace the engine coolant temperature sensor. Then go to Step 9.

STEP 3. Check harness connector B-106 at the engine coolant temperature sensor for damage.

Q. Is the harness connector in good condition?

YES Go to Step 4.

NO Repair or replace it. Harness Connector Inspection.
Then go to Step 9.

STEP 4. Check the continuity at engine coolant temperature sensor harness side connector B-106.

(1)Disconnect the connector B-106 and measure at the harness side.

(2)Check for the continuity between terminal No. 2 and ground.

- Continuity (2ohms or less)

Q. Does continuity exist?

YES Go to Step 7.

NO Go to Step 5.

STEP 5. Check harness connector B-20 at ECM [M/T] or PCM [A/T] for damage.

Q. Is the harness connector in good condition?

YES Go to Step 6.

NO Repair or replace it. Harness Connector Inspection.
Then go to Step 9.

STEP 6. Check for harness damage between engine coolant temperature sensor connector B-106 (terminal No. 2) and ECM [M/T] or PCM [A/T] connector B-20 (terminal No. 69).

Q. Is the harness connector in good condition?

YES Go to Step 8.

NO Repair or replace it. Harness Connector Inspection.
Then go to Step 9.

STEP 8. Check for harness damage between engine coolant temperature sensor connector B-106 (terminal No. 1) and ECM [M/T] or PCM [A/T] connector B-21 (terminal No. 93).

Q. Is the harness wire in good condition?

YES Replace the ECM or the PCM. When the ECM or the PCM is replaced, register the encrypted code. Immobilizer System.
Then go to Step 9.

NO Repair it. Then go to Step 9.

STEP 9. 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 Retry the troubleshooting.
NO The inspection is complete.