P0112
DTC P0112: Intake air temperature Circuit Low InputIntake Air Temperature Sensor Circuit Part 1:
Intake Air Temperature Sensor Circuit Part 2:
CIRCUIT OPERATION
- Approximately 5 volts are applied to the intake air temperature sensor output terminal (terminal No. 6) from the ECM (terminal No. 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
- 2 seconds or more have passed since the staring sequence was completed.
Judgement Criteria
- Intake air temperature sensor output voltage has continued to be 0.2 volt or lower [corresponding to an air intake temperature of 115 °C (239 °F) or higher] for 2 seconds.
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 Tool:
- 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. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991502 to the data reading mode for item 13, Intake Air Temperature Sensor.
- The intake air 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.
NO: Go to Step 2.
STEP 2. Check connector B-105 at the intake air temperature sensor for damage.
Q: Is the connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 6.
STEP 3. 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 No. 5 and No. 6.
- There should be continuity. (0.30 - 1.0 kiloohm)
Q: Is the measured resistance between 0.30 and 1.0 kiloohm?
YES: Go to Step 4.
NO: Replace the volume air flow sensor. Then go to Step 6.
STEP 4. Check for short circuit to ground between intake air temperature sensor connector B-105 and ECM connector C-115
Q: Is the harness wire in good condition?
YES: Go to Step 5.
NO: Repair it. Then go to Step 6.
STEP 5. Check connector C-115 at ECM
Q: Is the connector in good condition?
YES: Replace the ECM or PCM. Then go to Step 6.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 6.
STEP 6. Perform the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Trouble Code Diagnosis- OBD-II Drive Cycle - Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0112 set?
YES: Repeat the troubleshooting.
NO: The procedure is complete.