P0117
DTC P0117: Engine Coolant Temperature Circuit Low InputEngine Coolant Temperature Circuit:
CIRCUIT OPERATION
- 5-volt voltage is applied to the engine coolant temperature sensor output terminal (terminal No. 1) from the ECM (terminal No. 83) via the resistor in the ECM. The ground terminal (terminal No. 2) is grounded with ECM (terminal No. 92).
- 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 checks whether this voltage is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
- Engine coolant temperature sensor output voltage is out of specified range.
MONITOR EXECUTION
- Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored)
- Not applicable
Sensor (The sensor is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- 2 seconds or more have passed since the staring sequence was completed.
Judgement Criteria
- Engine coolant temperature sensor output voltage has continued to be 0.1 volt or lower [corresponding to a coolant temperature of 140 °C (284 °F) or higher] for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Engine coolant temperature sensor failed.
- Open or shorted engine coolant temperature sensor circuit, or connector damage.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Using scan tool MB991958, check data list item 21: 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 21, 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 How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check harness connector B-107 at the engine coolant temperature sensor for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Harness Connector Inspection. Then go to Step 6.
STEP 3. Check for short circuit to ground between engine coolant temperature sensor connector B-107 and ECM connector C-115.
Q: Is the harness wire in good condition?
YES: Go to Step 4.
NO: Repair it. Then go to Step 6.
STEP 4. Check harness connector C-115 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Harness Connector Inspection. Then go to Step 6.
STEP 5. Check the engine coolant temperature sensor.
1. Disconnect the engine coolant temperature sensor connector B-107.
2. Remove the engine coolant temperature sensor.
3. With the temperature sensing portion of engine coolant temperature sensor immersed in hot water, check 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 N.m (22 ± 6 ft.lb)
Q: Is the resistance at the standard value?
YES: Replace the ECM. Then go to Step 6.
NO: Replace the engine coolant temperature sensor. Then go to Step 6.
STEP 6. Perform the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0117 set?
YES: Repeat the troubleshooting.
NO: The procedure is complete.