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

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)...


 
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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!
 
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Mike225

Guest
All Toyota V8 engines are Bank 1 is Drivers side while Bank 2 is Passengers side.
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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Kevin

Guest
I would recommend replacing both sides. My CEL came on along with Trac OFF flashing and LO4 flashing. I ran an ordinary OBD2 scanner and the P106B code popped up. I didn't have a fancy scanner to tell me which bank was faulty, so I replaced both. I opened both old parts up and both were in bad shape with oxidation and moisture (6 year old Tundra with 70k miles). The driver's side (bank 1) was in worse shape, but both were pretty bad. For a part that's less than $200, replace both so you don't get the same CEL light in the near future.
 
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Gary

Guest
This is a very good forum answered my questions from just reading past comments thanks and keep up the good work you’ve really been a big help to me and I’m sure countless others
 
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Rich

Guest
I have a 2012 Tundra 4.6, my TRAC OFF light came on as well as the CHECK ENG light. They goes off when I reach a half tank. The codes that were pulled are C1201, P106B, P2440. The truck seems very sluggish and is not shifting properly, (automatic) without letting my foot off the gas then accelerating again.
 
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Riggs

Guest
I have a 2012 Tundra 4.6, my TRAC OFF light came on as well as the CHECK ENG light. They goes off when I reach a half tank. The codes that were pulled are C1201, P106B, P2440. The truck seems very sluggish and is not shifting properly, (automatic) without letting my foot off the gas then accelerating again.
Same
 
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Hannah

Guest
I have a 2012 tundra and the code is p106b, I just wanna know how much is it to get this fixed.
 
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Hewitt Tech

Guest
I have a 2012 tundra and the code is p106b, I just wanna know how much is it to get this fixed.
A lot of the time it is a damaged pressure sensor in the secondary air switching valves. This happens when the vehicle is driven with air switching valve stuck open codes. The only way to confirm which of the three sensors is causing the code is to compare the 2 AIP (air injection pressure) values and the evap pressure sensor value. Pretty much it will always be one of the air switching valve that had a valve stuck open code. The sensor that is reading more than 5-6kPa different than the other two on the freeze frame data needs to be replaced. This could mean replacing the air switching valve or the evap canister.
 
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