P0117
DTC P0117: Engine Coolant Temperature Circuit Low InputEngine Coolant Temperature Sensor Circuit:
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 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 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 for 2seconds.
FAIL-SAFE AND BACKUP FUNCTION
- Control as if the engine coolant temperature is 80°C.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. 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.
- 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 item6, 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.
NO : Go to Step 2.
STEP 2. Check harness connector B-08 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-08 (terminal No.1) and ECM connector B-09 (terminal No. 26).
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-09 at ECM 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.
Q: Is the engine coolant temperature sensor normal?
YES : Replace the ECM. When the ECM is replaced, register the ID code. 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 23. 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.