P0111

DTC P0111: Intake Air Temperature Circuit Range/Performance Problem (sensor 1)

Intake Air Temperature Sensor 1 Circuit:

CIRCUIT OPERATION
- Approximately 5 volts are applied to the intake air temperature sensor 1 output terminal (terminal No. 1) from the ECM (terminal No. 89) via the resistor in the ECM. The ground terminal (terminal No. 4) is grounded with ECM (terminal No. 88).
- The intake air temperature sensor 1 is a negative temperature coefficient type of resistor. When the intake air temperature rises, the resistance decreases.
- The intake air temperature sensor 1 output voltage increases when the resistance increases and decreases when the resistance decreases.

TECHNICAL DESCRIPTION
- The intake air temperature sensor 1 converts the intake air temperature to a voltage.
- The ECM checks whether this voltage is within a specified range.

DESCRIPTIONS OF MONITOR METHODS
Intake air temperature sensor 1 output voltage does not change when specified go/stop operations are repeated.

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)
- Engine coolant temperature sensor

DTC SET CONDITIONS

Logic Flow Chart

Logic Flow Chart:

Check Conditions
- Engine coolant temperature is higher than 76°C (169°F).
- Repeat 2 or more times: drive*1, stop*2.
Drive*1: vehicle speed higher than 50 km/h (31 mph) lasting a total of 60 seconds or more.
Stop*2: vehicle speed lower than 1.5 km/h (1.0 mph) lasting 30 seconds or more.

Judgement Criterion
- Changes in the intake air temperature is lower than 1°C (1.8°F).

FAIL-SAFE AND BACKUP FUNCTION
- Control as if the intake air temperature is 25°C.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 7. OBD- II Drive Cycle

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Intake air temperature sensor 1 failed.
- Harness damage 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 5: Intake Air Temperature Sensor 1.







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. Remove the mass airflow sensor from the air intake hose.
3. Turn the ignition switch to the "ON" position.
4. Set scan tool MB991958 to the data reading mode for item5, Intake Air Temperature Sensor 1.







5. Heating the sensor using a hair drier.
- The indicated temperature increases.

NOTE: Do not allow it to increase over 80°C (176°F).

6. Turn the ignition switch to the "LOCK" (OFF) position.
7. Attach the mass airflow sensor.

Q: Is the sensor operating properly?

YES : It can be assumed that this malfunction is intermittent.

NO : Go to Step 2.

STEP 2. Check the intake air temperature sensor 1.

1. Disconnect the intake air temperature sensor 1 connector A-07.







2. Measure the resistance between intake air temperature sensor 1 side connector terminal No. 1 and No. 4.







3. Measure resistance while heating the sensor using a hair drier.

Standard value:
13 - 17 kohms [at - 20°C (- 4°F)]
5.4 - 6.6 kohms [at 0°C (32°F)]
2.3 - 3.0 kohms [at 20°C (68°F)]
1.0 - 1.5 kohms [at 40°C (104°F)]
0.56 - 0.76 kohms [at 60°C (140°F)]
0.31 - 0.43 kohms [at 80°C (176°F)]

Q: Is the measured resistance at the standard value?

YES : Go to Step 3.

NO : Replace the mass airflow sensor. Then go to Step 9.

STEP 3. Check harness connector A-07 at the intake air temperature sensor 1 for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 4.

NO : Repair or replace it. Then go to Step 9.

STEP 4. Check the continuity at intake air temperature sensor 1 harness side connector A-07.

1. Disconnect the connector A-07 and measure at the harness side.







2. Check for the continuity between terminal No. 4 and ground.
- Continuity (2 ohms or less)

Q: Does continuity exist?

YES : Go to Step 7.

NO : Go to Step 5.

STEP 5. Check harness connector B-10 at ECM for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 6.

NO : Repair or replace it. Then go to Step 9.

STEP 6. Check for harness damage between intake air temperature sensor 1 connector A-07 (terminal No. 4) and ECM connector B-10 (terminal No. 88).

Q: Is the harness wire in good condition?

YES : Replace the ECM. When the ECM is replaced, register the ID code. Then go to Step 9.

NO : Repair it. Then go to Step 9.

STEP 7. Check harness connector B-10 at ECM for damage.

Q: Is the harness connector in good condition?

YES : Go to Step 8.

NO : Repair or replace it. Then go to Step 9.

STEP 8. Check for harness damage between intake air temperature sensor 1 connector A-07 (terminal No. 1) and ECM connector B-10 (terminal No. 89).

Q: Is the harness wire in good condition?

YES : Replace the ECM. When the ECM is replaced, register the ID code. 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 7. OBD- II Drive Cycle
2. Check the diagnostic trouble code (DTC).

Q: Is DTC P0111 set?

YES : Retry the troubleshooting.

NO : The inspection is complete.