P0110
DTC P0110 INTAKE AIR TEMPERATURE SENSOR1 CIRCUITComponent Location:
GENERAL DESCRIPTION
The Intake Air Temperature (IAT) sensor measures the temperature of engine intake air. The Intake Air Temperature (IAT) sensor is a thermistor (a variable resistor that changes along with outside air temperature) in series with a fixed resistor in the PCM. The PCM applies 5 Volts to the AT sensor. The PCM monitors the voltage across the AT sensor and converts it into a temperature reading. When the outside air temperature is cold the IAT sensor resistance is high, and when the outside air temperature is warm the IAT sensor resistance is low. Therefore, when the air temperature is cold the PCM will receive a high voltage input, and when the air temperature is warm the PCM will receive a low voltage input. The signal from IAT sensor is used for injection time correction (Cold post start correction), ignition angle correction(Air temperature correction) and idle speed correction(Air-density correction).
DTC DESCRIPTION
This test has two parts ? the Stuck Start Test and the Stuck Drive test. The logic checks for movements in the IAT by comparing the mm and max IAT values. If a sufficient difference is present, both parts of the test declare a PASS. Otherwise, the start-up portion of the stuck test sets a sensor stuck" flag and increments a counter while monitoring the mm and max IAT. If the stuck condition persists, the counter eventually reaches its threshold and the start-up test completes with the sensor struck flag set.
If a PASS is not declared as mentioned above, the Drive portion of the stuck test also sets a sensor stuck" flag and then checks for enough engine load to be present and if it is, it increments a counter. If the stuck condition persists and the engine continues to experience at least the minimum load, the counter eventually reaches its threshold indicating that enough engine heating as well as airflow introduction has taken place and sets a drive conditions complete flag. It then waits for the engine to return to idle. Once at idle, an idle counter is incremented until it reaches its threshold (as long as the stuck conditions persists). This completes the drive test and also the entire Stuck Test.
PCM monitors difference MAX. and MIN IATS in order to detect movement in IATS through Start Test and Drive Test while enable condition is met. If PCM detects intake air temperature does not change PCM determines that a fault exists and a DTC is stored.
MIL(Malfunction Indication Lamp) turns on when the malfunction lasts till consecutive 2 driving cycle.
DTC Detecting Condition:
Specification:
Schematic Diagram:
Signal Waveform And Data:
SIGNAL WAVEFORM AND DATA
The output signals of IATS & ECTS change smoothly without any rapid changes. Those have almost same characteristic signal during the early period after start. It means that the temperatures of intake air and engine coolant are depended on the temperature of atmosphere. Meanwhile, during the warming up, the output signal of ECTS is going up increasingly. but, the output signal of IATS changes a little bit. even it may not change almost. It means that the heat of engine does not affect on the temperature of intake air.
MONITOR SCANTOOL DATA
1. IG "OFF" & connect Scantool.
2. ENG "ON" and warm-up the engine to normal operating temperature.
3. Monitor "IATS" item on the service data.
4. Is the "IATS" data displayed correctly?
YES: Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
NO: Go to "Terminal and Connector Inspection" procedure
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES: Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO: Go to "Signal Circuit Inspection" procedure.
SIGNAL CIRCUIT INSPECTION
1. IG "OFF" and disconnect IATS connector.
2. IG "ON" and ENG "OFF"
3. Measure voltage between terminal 4 of IATS harness connector and chassis ground.
Specification : Approx.5 V
4. Is the measured voltage within specification?
YES: Check short to battery in harness.
If O.K, go to "Ground Circuit Inspection" procedure.
If N.G, repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO: Repair open or short to ground in harness and go to "Verification of Vehicle Repair" procedure.
GROUND CIRCUIT INSPECTION
1. IG "OFF" and disconnect IATS connector.
2. Measure voltage terminal 4 of IATS harness connector and chassis ground.
3. Measure voltage terminal 4 and 5 of IATS harness connector.
Specification : Voltage difference between measurement "A" and "B" is below 200mV.
4. Is the measured voltage within specification ?
YES: Go to "Component Inspection" procedure.
NO: Repair contact resistance or open in harness and go to "Verification of Vehicle Repair" procedure.
COMPONENT INSPECTION
1. Check resistance of IATS
1. IG "OFF" and disconnect IATS connector.
Specification:
2. Measure resistance between terminal 4 and 5 of IATS connector.(Component Side)
3. Is the measured resistance within specification ?
YES: Go to "Check PCM" as follows.
NO: Substitute with a known - good IATS and check for proper operation. If the problem is corrected, replace IATS and go to "Verification of Vehicle Repair" procedure.
2. Check PCM
1. IG "OFF" and connect Scantool.
2. Disconnect IATS connector and connect probe to terminal 4 of IATS harness connector.
3. IG "ON" and ENG "OFF" and simulation Function on Scantool.
4. Simulate voltage at terminal 4 of IATS harness connector.
5. Does the signal value of IAT sensor change according to simulation voltage?
YES: Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO: Substitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.
NOTE: There is a memory reset function on Scantool that can erase optional parts automatically detected and monetized by PCM. Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code(DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions
4. Monitor that all readiness tests have been verified as "Complete"
5. Are any DTCs present?
YES: Go to the applicable trouble shooting procedure.
NO: System is performing to specification at this time.