P0117
DTC P0117: Engine Coolant Temperature Circuit Low InputCAUTION: If DTC P0117 has been set, TCL and air conditioner related DTC U1120 is also set. After P0117 has been diagnosed, don't forget to erase DTC U1120.
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 PCM (terminal No. 93) via the resistor in the PCM. The ground terminal (terminal No. 2) is grounded with PCM (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 PCM 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 below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Condition
- 2 seconds or more have passed since the engine starting sequence was completed.
Judgement Criterion
- Engine coolant temperature sensor output voltage has continued to be 0.1 volt or lower [corresponding to 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 - Pattern 21. OBD-II Drive Cycle
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Engine coolant temperature sensor failed.
- Shorted engine coolant temperature sensor circuit, or connector damage.
- PCM 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 How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions.
NO: Go to Step 2.
STEP 2. Check harness connector B-06 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. Then go to Step 6.
STEP 3. Check for short circuit to ground between engine coolant temperature sensor connector B-06 (terminal No. 1) and PCM connector B-21 (terminal No. 93).
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 B-21 at PCM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Then go to Step 6.
STEP 4. Check harness connector B-21 at PCM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Then go to Step 6.
STEP 5. Check the engine coolant temperature sensor.
1. Disconnect the engine coolant temperature sensor connector B-06.
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 ± 7 ft-lb)
Q: Is the measured resistance at the standard value?
YES: Replace the PCM. When the PCM is replaced, register the encrypted code. Refer to Encrypted Code Registration Criteria Table. Then go to Step 6.
NO: Replace the engine coolant temperature sensor. Then go to Step 6.
STEP 6. 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 21. OBD-II Drive Cycle
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0117 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.