P0112
Intake Air Temperature Sensor Circuit:
Connectors:
Connectors:
DTC P0112: Intake air temperature Circuit Low Input
CIRCUIT OPERATION
- Approximately 5 volts are applied to the intake air temperature sensor output terminal (terminal No. 6) from the ECM (terminal No. 62)
- 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
DESCRIPTIONS OF MONITOR METHODS
Intake air 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:
Check Conditions
- 2 seconds or more have passed since the engine starting 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.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
- Intake air temperature sensor failed.
- Shorted intake air temperature sensor circuit connector damage.
- 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 INTRODUCTION, How to Use Troubleshooting/Inspection Service Points How to Cope with Intermittent Malfunctions.
NO: Go to Step 2.
STEP 2. Check connector B-14 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-14.
2. Measure the resistance between intake air temperature sensor side connector terminals No. 5 and No. 6.
- There should be continuity. (0.30 - 20 kohms)
Q: Is the measured resistance between 0.30 and 20 kohms?
YES: Go to Step 4.
NO: Replace the volume airflow sensor. Then go to Step 6.
STEP 4. Check for short circuit to ground between intake air temperature sensor connector B-14 (terminal No. 6) and ECM connector C-118 (terminal No. 62)
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-118 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. 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 - Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0112 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.