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Toyota Tundra or Tacoma with Code P106B Secondary Air Injection Pressure Sensor Correlation

Discussion in 'Tech Help' started by Lewis, Jul 3, 2017.

  1. Lewis

    Lewis Moderator Staff Member

    If you get this P106B code in one of your Toyota vehicles like the Tundra or Tacoma, you will want to understand how the ECM determines whats at fault.

    There are 3 pressure sensors that perform a self check 50 minutes after your truck is shut off. One of the sensors is the EVAP pressure sensor in the charcoal canister.

    The other two are the pressure sensors in the air switching valves. If during the check there is a significant difference between the readings of those sensors, the ECM interprets that as a malfunction and sets the P106B code.

    To find out which sensor is faulty, you need a good scan tool (such as the Toyota Techstream, a snap-on or mac scanner, not a basic code checker) that can read the ECM data list.

    Look at the pressure readings from the Freeze Frame Data (stored code)
    **You may not see the Vapor Pressure Pump reading in the FF stored data as Toyota didn't seem to capture it. At least from what I've seen. You can still look at the Live Data (current) and see what its reading. It may be in/around 762mmhg (convert if needed)

    Vapor Pressure Pump sensor
    Air Pump Pressure sensor (Absolute)
    Air Pump2 Pressure sensor (Absolute)

    If any one of the values differs from the atmospheric pressure by +/- 3.5 kPa (+/- 26.25 mmHg) or more, there is a malfunction in that sensor. If the vapor pressure sensor is faulty, replace the charcoal canister. If one of the air pump sensors is faulty, replace the corresponding air switching valve.

    Here is what the valve in question looks like..

    Toyota 25701-38100 Air Pump Switching Valve

    In this example (V8), the FF Data shows us that Air Pump Pressure (Bank 1) is the culprit with a reading of -1 (the reading of -1 is equal to 51.71mmhg which is almost twice the threshold limit)


    Here is the Secondary Air Injection Valve for Bank 1....


    If we open it up and look, this is what we find....


    The bank 2 valve was also inspected and found to be also in need of replacing (customer requested)....


    If you have a V6 engine, the valve set with come as an assembly (meaning both are included and cannot be purchased separately)...

  2. Mike 225

    Mike 225 Guest

    I have the P106B code on my 2012 Tundra 4.6L. My reader shows that the following
    Air Pump Pressure 1 13.485 psi (converted to 697 mmHg)
    Air Pump Pressure 2 14.500 psi (converted to 749 mmHg)
    This tells me that Air Pump Pressure 1 is the culprit.
    I've read mixed answers as to which valves are bank 1 and bank 2.
    Is this in fact the drivers side? Which I believe to be part # 25702-38050
    Or is it the passenger side?

    Thanks for your help!
  3. Lewis

    Lewis Moderator Staff Member

    All Toyota V8 engines are Bank 1 is Drivers side while Bank 2 is Passengers side.
  4. Mike225

    Mike225 Guest

    Great, thank you for clarifying! I'm glad I checked. I almost ordered the part number shown in the original post (25701-38100). It looks like I need the other one.

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