Q: Check engine light keeps coming on

asked by on May 19, 2016

My Check Engine Light has come on three times in the first month since I bought my car, always around 60 mph on the highway. It runs fine despite the light, and I haven't had any issues. When I have the code checked, it is "P026a00". The first time this happened, the dealership cleared it and assured me it wouldn't happen again. The second time, they cleared it and it didn't appear for nearly 100 miles. The THIRD time, a few hundred miles later, I am being told they will order a "Charge Air Pressure" sensor for the car. Once it's installed, they want to drive my car at least 100 miles to make sure it's working properly. While I wait for the car to come back, what are your thoughts? What could cause this?

Unfortunately, the repair information I have for this vehicle and code are rather sparse. Doing a little research, I found this code stands for "Charge Air Cooler Efficiency Below Threshold."

The most common cause of this code does appear to be the charge air sensor, otherwise known as the intake air temperature sensor or manifold temperature sensor. This sensor is used to measure the temperature of air entering the engine.

The powertrain control module (PCM), (also known as the electrical control unit) sends a reference voltage to the sensor. The internal resistance of the sensor varies according to temperature, and that signal is sent back to the PCM.

Generally, a professional technician can test this sensor without much of a problem. I suggest you have your sensor tested before replacing it. The team at YourMechanic would be happy to help with a diagnostic inspection.

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