P0106 is a very common OBD2 trouble code that can occur in the Toyota Prius. Simply put, this code indicates that the signal coming from the MAP sensor is not what it should be.
P0106 Definition: MAP Sensor – Range/Performance
P0106 is a generic OBD2 code, which means that it has the same definition for the Toyota Prius as it would any other vehicle.
Here’s the definition of P0106, provided with the understanding it can help make diagnosing it a little bit easier.
The MAP (Manifold Absolute Pressure) sensor records the pressure in the intake manifold and reports it to the ECM. It can also be referred to as the barometric pressure sensor as well. For this article, the terms are interchangeable.
Circuit Range/Performance Issue
The MAP sensor sends the current intake pressure reading to your Prius’s ECM in the form of a voltage signal.
The signal should INCREASE (more voltage) as the engine load increases.
When the signal is not responding in kind with engine load and throttle position, P0106 will be stored, and the check engine light will come on.
P0106 Symptoms: Toyota Prius
With the MAP sensor not working properly, your Prius’s drivability will suffer. Here are some of the most common symptoms of P0106 you could be observing:
Toyota Prius P0106 Causes + Diagnosis
Here are the most common causes associated with P0106 and a proper order to diagnose your Prius in. Your first impulse may be to install a MAP sensor and be done with it. And, if you have the money to throw at the problem, you may very well get lucky.
If you don’t want to make an unnecessary purchase, we’ll go over how to diagnose and test the MAP sensor before you replace it.
Related: Toyota Prius P0107 MAP Circuit Low
Before testing the MAP sensor, do a quick inspection of your Toyota Prius’s wiring harness. Then, follow the connection from the MAP sensor to where it meets the rest of the harness.
Make sure the ground is solid.
If the wiring is brittle, cracked, exposed, or damaged in any other way, repairing it will likely clear P0106. Also, examine the pins where the MAP sensor plugs into the wiring harness.
Test The MAP Sensor Voltage
Here’s how to go about testing a MAP sensor with a multimeter. You are trying to determine if the voltage going to the MAP sensor is correct and that the voltage is changing when the throttle is pushed.
If the voltage is OK going to the MAP sensor, but not increasing or decreasing in the output circuit, that indicates a bad MAP sensor is causing P0106.
This video from Ratchets and Wrenches covers exactly how to test the MAP with the multimeter.
Other P0106 Causes
While a bad MAP sensor or wiring issues are far and away the most common reasons you’ll bump into P0106 in the Toyota Prius, there are other (less common) causes as well. Here they are:
- BAD ECM
- Bad ground wire
P0106 in the Prius is almost always fixed by replacing the MAP sensor or repairing the wiring harness.
If there’s anything that you have to say that could help the next person with their vehicle, your comment is most welcome.