P0111
Intake Air Temperature Sensor Circuit:
CIRCUIT OPERATION
- Approximately 5 volts are applied to the intake air temperature sensor output terminal (terminal 6) from the ECM (terminal 72)
- 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
DTC SET CONDITIONS
Check Conditions
- Engine coolant temperature is higher than 76 °C (169 °F).
- Repeat 5 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 (0.9 mph) lasting more than 30 seconds.
Judgement Criteria
- Changes in the intake air temperature is lower than 1 °C (1.8 °F).
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Intake air temperature sensor failed.
- Open or shorted intake air temperature sensor circuit, or loose connector.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tools
- MB991502: Scan Tool (MUT-II)
STEP 1. Using scan tool MB991502, check data list item 13: Intake Air Temperature Sensor.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Remove the air intake hose from the volume air flow sensor.
3. Turn the ignition switch to the "ON" position.
4. Set scan tool MB991502 to the data reading mode for item 13, 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 air intake hose.
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 the intake air temperature sensor.
1. Disconnect the intake air temperature sensor connector B-105.
2. Measure the resistance between intake air temperature sensor side connector terminal 5 and 6.
3. Measure resistance while heating the sensor using a hair drier.
Standard value:
13 - 17 kohm (at -20 °C (-4 °F)]
5.3 - 6.7 kohm (at 0 °C (32 °F)]
2.3 - 3.0 kohm [at 20 °C (68 °F)]
1.0 - 1.5 kohm [at 40 °C (104 °F)]
0.56 - 0.76 kohm [at 60 °C (140 °F)]
0.30 - 0.42 kohm [at 80 °C (176 °F)]
Q: Is the resistance at the standard value?
YES: Go to Step 3.
NO: Replace the volume air flow sensor Then go to Step 9.
STEP 3. Check connector B-105 at the intake air temperature sensor for damage.
Q: Is the connector in good condition?
YES: Go to Step 4.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 9.
STEP 4. Check the continuity at intake air temperature sensor harness side connector B-105.
1. Disconnect the connector B-105 and measure at the harness side.
2. Check for the continuity between terminal 5 and ground.
- Should be less than 2 ohm.
Q: Is the continuity normal?
YES: Go to Step 7.
NO: Go to Step 5.
STEP 5. Check connector C-119 at ECM
Q: Is the connector in good condition?
YES: Go to Step 6.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 9.
STEP 6. Check for open circuit and harness damage between intake air temperature sensor connector B-105 and ECM connector C-119
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 9.
NO: Repair it. Then go to Step 9.
STEP 7. Check connector C-115 at ECM
Q: Is the connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 9.
STEP 8. Check for open circuit and harness damage between intake air temperature sensor connector B-105 and ECM connector C-115
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. 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, Procedure 6 Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is the DTC P0111 output?
YES: Retry the troubleshooting.
NO: The inspection is complete.