P0099 OBD Error Code: Problem & Solutions

<<See All OBD Codes

Oftentimes, Engine Warning Light turns up almost immediately it senses the OBD code error. This directly impacts the engine performance as it struggles with power and acceleration as well as failed fuel system causing increased consumption of fuel by the engine.

OBD-II Code Decreased engine performance is defined as an Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic.

OBD code P0099 means that the Powertrain Control Module (PCM) has detected an intermittent input signal from the Intake Air Temperature (IAT) sensor 2 circuit. The PCM uses the IAT input signal and the Mass Air Flow (MAF) sensor input signal to calculate fuel delivery and ignition timing strategy. The IAT sensor is very important as maintaining a correct air/fuel ratio (typically 14:1) is critical to engine performance and fuel efficiency.

If the PCM detects a certain number of intermittent signals from the IAT sensor 2, over a set period of time, a code P0099 will be stored and a Malfunction Indicator Lamp (MIL) gets illuminated.

What causes the problem of Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic?

• Open or shorted IAT sensor 2 wiring and/or connectors
• Defective IAT sensor 2
• Faulty MAF sensor
• Clogged air filter
• Broken intake air inlet pipe

1. Engine Control Module - OBD Error Code P0099 can simply be due to faulty ECM. Replace old and damage components now!
2. Diagnostic Tool - Choose from our wide variety of diagnostic tools to detect and correct the OBD code error.
3. Air Temperature Sensor - The Air Temperature sensor is important for internal combustion system, and plays an important role in the engine output. Replace faulty sensor now!
4. Air Flow Sensor Connector - It is very important component as it provides vital information regarding the air intake to the engine control unit. Replace faulty connectors with us!

Since this code is likely points to the problem on the IAT circuit, there may not be any noticeable big symptoms at present and even if there are any can we considered as general problems by the driver. However, the MIL will likely be on and the car may exhibit some drivability problems.

Common Symptoms

• The Check Engine Light On indicating OBD code error
• Engine running rough or not starting at all
• Engine hesitant, or surge while driving
• Loss of acceleration and throttle response
• Engine Misfires
• Poor Engine Performance

It is important to identify the components affected and leading to OBD code P0099 getting stored in the PCM and getting flashed. Following are the parts that can be repaired or replaced to correct this problem.

 

• Replace faulty Intake Air Temperature Sensor and Circuit
• Repair or replace damaged wiring/connections to the IAT Sensor
• Replace PCM (Powertrain Control Module) if damaged and can also be reprogrammed if found faulty and tested again if the error reappears or not

Find quality replacement parts at Parts Avatar Canada for all your vehicle make and model at the best prices in the market

Use an advanced scan tool capable of factory sensor readings (not just one from an auto parts store) to correct the OBD Code P0099 error. A qualified technician can read the data from the advanced scan tool to determine when the problem occurred, or if it is still occurring.

 

• Visually inspect the electrical connections and wire harness to the intake air temperature sensor for the damaged and breakages.
• Scans and documents engine codes using a professional diagnostic tool and freeze frame data for when the sensor failed.
• Scans the IAT sensor 2 and compares the output to manufacturer’s specifications for the time when it failed. They will lightly tap the sensor to see if the reading is erratic.
• Disconnect the IAT sensor 2 connector and verifies that the temperature reading and note if it goes below -4° F.
• Two connector wires are shorted together and noted if temperature readings go above 212° F.
• Use a multimeter to check that the ohms of the IAT sensor 2 is within specifications while lightly tapping on sensor to see if the reading is erratic indicating a sensor internal failure.
• Check for faulty ECU (Engine Control Unit) and PCM (Powertrain Control Module) for problematic electronic components and if requires reprogramming.

Common Mistakes When Diagnosing The P0099 Code

 

Some of the common mistakes done while changing diagnosing the OBD code P0099 are:

 

• Improper assessment of the IAT sensor failure
• Simply replacing the Powertrain Control Module (PCM) without considering other possibilities of problem
• Not noticing the damaged or loosened wiring and circuit problems