P0111

DTC P0111: Intake Air Temperature Circuit Range/Performance Problem

CAUTION:
If DTC P0111 has been set, TCL related DTC U1120 is also set. After P0111 has been diagnosed, don't forget to erase DTC U1120.

CIRCUIT OPERATION

- Approximately 5 volts are applied to the intake air temperature sensor output terminal (terminal No. 1) from the ECM [M/T] or the PCM [A/T] (terminal No. 107) via the resistor in the ECM [M/T] or the PCM [A/T]. The ground terminal (terminal No. 4) is grounded with ECM [M/T] or PCM [A/T] (terminal No. 69).
- The intake air temperature sensor is a negative temperature coefficient type of resistor. When the intake air temperature rises, the resistance decreases.
- The intake air temperature sensor output voltage increases when the resistance increases and decreases when the resistance decreases.

TECHNICAL DESCRIPTION

- The intake air temperature sensor converts the intake air temperature to a voltage.
- The ECM [M/T] or the PCM [A/T] checks whether this voltage is within a specified range.

DESCRIPTIONS OF MONITOR METHODS

Intake air temperature sensor 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)

- Not applicable

DTC SET CONDITIONS

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 more than 60 seconds.
Stop*2: vehicle speed lower than 1.5 km/h (1.0 mph) lasting more than 30 seconds.
Judgement Criterion

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

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 8 Monitors, Trips, Drive Cycles and Readiness Codes .

TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)

- Intake air temperature sensor failed.
- Open intake air temperature sensor circuit, 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 5: Intake Air 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)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 item 5, Intake Air Temperature Sensor.

(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. How to Cope With Intermittent Malfunctions.

NO Go to Step 2.

STEP 2. Check the intake air temperature sensor.

(1)Disconnect the intake air temperature sensor connector B-09.

(2)Measure the resistance between intake air temperature sensor 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)]
5.3 - 6.7 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)]
0.30 - 0.45 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 B-09 at the intake air 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 intake air temperature sensor harness side connector B-09.

(1)Disconnect the connector B-09 and measure at the harness side.

(2)Check for the continuity between terminal No. 4 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 open circuit and harness damage between intake air temperature sensor connector B-09 (terminal No. 4) 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 open circuit and harness damage between intake air temperature sensor connector B-09 (terminal No. 1) and ECM [M/T] or PCM [A/T] connector B-21 (terminal No. 107).

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 8 Monitors, Trips, Drive Cycles and Readiness Codes.

(2)Check the diagnostic trouble code (DTC).

Q. Is DTC P0111 set?

YES Retry the troubleshooting.
NO The inspection is complete.