P2199 Intake Air Temperature Sensor 1/2 Correlation

Description and meaning of DTC p2199

This generic powertrain diagnostic trouble code (DTC) typically applies to many OBD-II vehicles. That may include but is not limited to vehicles from Ford, Chevrolet, GMC, VW, Pontiac, Honda, Nissan, Mazda, etc. If you have been faced with diagnosing a code P2199, you need to know that it means that the powertrain control module (PCM) has detected a discrepancy in the correlating signals between two separate intake air temperature (IAT) sensors. Multiple IAT sensors are normally used exclusively in vehicles with more than one throttle body. Separate IAT sensors are monitored in comparison (with each other) primarily to ensure that no obstructions are impeding air flow to either side of the engine intake. Typical IAT sensor composition includes a thermal resistor that protrudes from a plastic housing on a two-wire pedestal. The plastic housing is inserted into the air intake pipe or air filter housing and sealed with a soft rubber grommet. Another IAT sensor design integrates the thermal resistor into the mass air flow (MAF) sensor housing. The thermal resistor may be parallel with the MAF sensor hot wire or in a recessed area away from air flow. The IAT sensor thermal resistor extends into the air inlet so that intake air flows across it as it is drawn into the intake. As intake air temperature increases, the level of resistance in the IAT resistor decreases. This causes circuit voltage to move towards the maximum reference point. When intake air is cooler, IAT sensor resistance increases, resulting in decreased IAT sensor circuit voltage. The PCM receives these variations in IAT sensor signal voltage as changes in intake air temperature. It also makes a comparison between individual IAT sensor signals and reacts accordingly. A code P2199 will be stored and a malfunction indicator lamp (MIL) may be illuminated if the PCM detects voltage signals from the separate IAT sensors which differ by more than the maximum allowable threshold. MIL illumination may require multiple ignition cycles with a failure.

p2199 diagnostic trouble code symptoms

Symptoms of a P2199 trouble code may include:Diminished engine performanceReduced fuel efficiencyHesitation upon acceleration

DTC p2199 - possible causes

Causes for this code may include:IAT sensor disconnectedDefective IAT sensorRestricted air filterOpen or shorted circuits or connectorsDefective PCM or PCM programming error

How to fix OBD-II diagnostic trouble code p2199

Begin with an inspection of the air filter element. It should be inserted into the housing as intended - free of dirt and debris. If the air filter element is relatively clean and installed properly, perform a visual inspection of IAT sensor system wiring and connectors. A diagnostic scanner, an infrared thermometer (with a laser pointer), a digital volt/ohmmeter (DVOM), and a source of reliable vehicle information will be needed to diagnose a P2199. Upon completion of a visual inspection, connect the scanner to the vehicle diagnostic port and retrieve all stored codes and freeze frame data. Write this information down for later. Clear the codes and test-drive the vehicle to see if the P2199 is reset. Obtain diagnostic flow charts, wiring diagrams, connector pin-out charts, component testing procedures/specifications, and connector face views from your vehicle information source. This kind of information, in addition to applicable technical service bulletins, may be instrumental in the diagnostic process. Disconnect the PCM (and all related controllers) before testing individual system circuits with the DVOM. This will help to prevent controller damage. Test each IAT sensor:Use the DVOM to test the IAT sensors Place the DVOM on the ohms settingDisconnect the sensor being tested Follow manufacturer&rsquos component testing specificationsSensors which fail to comply with testing specifications should be considered defectiveTest the reference circuit:Use the DVOM to test reference (typically 5V) voltage With the key on and the engine off (KOEO), disconnect each IAT sensor connectorUsing the positive test lead of the DVOM, probe the reference circuit pin of the IAT sensor connector At the same time, probe the ground pin with the negative test lead of the DVOMReference voltage should be detectedIf it is not, test the same circuit at the PCM connector. If no reference voltage signal is detected there, suspect a PCM problem or a programming error. Test each IAT sensor signal circuit:Test each IAT sensor signal circuit using the DVOMPlug-in the IAT sensor Use the positive test lead of the DVOM to probe the signal circuit of each sensor The negative test lead should be connected to a chassis or engine groundThe infrared thermometer will be used to check actual IAT Compare the individual IAC sensor signal voltage levels at the sensor connectors with actual IAT as reflected on the infrared thermometer Use the temperature to voltage chart (found within the vehicle information source) to determine if each sensor is functioning properly This is done by comparing individual IAT sensor data (collected in step 6 of the previous section) with desired IAT voltage (reflected on the temp to voltage chart). If either of the IAT sensors do not reflect the appropriate degree of voltage (according to the temp to voltage chart) suspect that it is faulty. If IAT and ambient air temperature sensor signal circuits both reflect the appropriate amount of voltage:Use the DVOM to test the signal circuit (for the sensor in question) at the PCM connector Consider that an open circuit exists between the IAT and the PCM if there is an appropriate sensor signal at the sensor connector but not at the PCM connector Applicable technical service bulletins (TSB) will likely help you with your diagnosis

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