P0110
Intake Air Temperature Sensor Circuit:
CIRCUIT OPERATION
- Approximately 5-volt voltage is applied to the intake air temperature sensor output terminal (terminal 6) from the PCM (terminal 64) via the resistor in the PCM. The ground terminal (terminal 5) is grounded with PCM (terminal 57).
- The intake air temperature sensor is a negative temperature coefficient type of resistor. It has the characteristic that 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 PCM checks whether this voltage is within a specified range.
DTC SET CONDITIONS
Check Conditions
- Two seconds or more have passed since the engine was started.
Judgement Criteria
- Intake air temperature sensor output voltage has continued to be 4.6 volts or higher [corresponding to an air intake temperature of -45 °C (-49 °F) or lower] for 2 seconds.
or
- Intake air temperature sensor output voltage has continued to be 0.2 volt or lower [corresponding to an air intake temperature of 125 °C (257 °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.
- PCM failed.
DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB9915O2.
STEP 1. Using scan tool MB991502, check data list item 13: Intake Air Temperature Sensor.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "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.
If they match, this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope With Intermittent Malfunction.
If they don't match, go to Step 2.
STEP 2. Check the intake air temperature sensor.
1. Disconnect the intake air temperature sensor connector B-14.
2. Measure the continuity between the intake air temperature sensor side connector terminals 5 and 6.
- There should be continuity. (0.14 - 50 kOhms)
If continuity, go to Step 3.
If no continuity, replace the volume air flow sensor.
Then go to Step 8.
STEP 3. Check the circuit at intake air temperature sensor connector B-14.
1. Disconnect connector B-14 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 6 and ground.
- Voltage should be between 4.5 and 4.9 volts.
4. Turn the ignition switch to "LOCK" (OFF) position.
5. Check for the continuity between terminal 5 and ground.
- Should be less than 2 ohms.
If all checks above meet the specifications, go to Step 4.
If any check above does not meet the specifications, go to Step 5.
STEP 4. Check harness connector B-14 at the intake air temperature sensor for damage.
If harness connector B-14 is in good condition, replace the volume air flow sensor.
Then go to Step 8.
If harness connector B-14 is damaged, repair or replace it.
Refer to Harness Connector Inspection.
Then go to Step 8.
STEP 5. Check harness connector C40 at the PCM for damage.
If harness connector C-40 is in good condition, go to Step 6.
If harness connector C-40 is damaged, repair or replace it.
Refer to Harness Connector Inspection.
Then go to Step 8.
STEP 6. Check the harness wire between intake air temperature sensor connector B-14 and PCM connector C40.
If the wire between intake air temperature sensor connector B-14 and the PCM connector C-40 is not damaged, go to Step 7.
If the wire between intake air temperature sensor connector B-14 and PCM connector C-40 is damaged, repair it. Then go to Step 8.
STEP 7. Check the intake air temperature sensor.
1. Disconnect intake air temperature sensor connector B-14.
2. Measure the resistance between intake air temperature sensor side connector terminals 5 and 6.
Standard value:
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 (68 °F)]
0.30 - 0.42 kOhms [at 80 °C (176 °F)]
3. Measure resistance while heating the sensor using a hot dry air.
- As the temperature rises, the resistance value should drop.
If within specifications, replace the PCM. Then go to Step 8.
If not within specifications, replace the volume air flow sensor. Then go to Step 8.
STEP 8. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Read the diagnostic trouble code, and confirm that diagnostic trouble code P0110 does not reset.