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06 Silverado Engine Code that keeps coming back

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by RSSebura, Apr 4, 2012.

  1. RSSebura

    RSSebura New Member

    Hey everyone, I have an 06 Silverado that keeps throwing a double code. The code numbers are P2A01 and P2A04. Both codes come back as oxygen sensors, bank 1 sensor 2 and bank 2 sensor 2. When I look up the information on these codes, all it says is that they are performance codes. I have talked with several repair shops and none seem to know what this code is or what causes it. I was thinking exhaust leak, but cant find one. Could it be bad sensors since they both appear to have been replaced?
  2. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    From what I gathered, you have either bad sensors, or if the sensors were moved further downstream as a result of after-market headers being installed (IF it is also throwing a heater code). Below is the most thorough information I could find.


    DTC P2A01: HO2S Performance Bank 1 Sensor 2 , Post Cat. O2.
    • The Engine Run Time parameter is more than 5 minutes.

    • The ignition 1 Signal parameter is between 10-18 volts.

    • The MAF sensor parameter is between 3-50 g/s.

    • The Engine Speed parameter is between 500-5,000 RPM.

    • The Vehicle Speed parameter is between 24-132 km/h (15-82 mph).

    • The Fuel Level Sensor parameter is more than 10 percent.

    • The Short Term FT parameter is between -4 and +4 percent.

    • DTC P2A01 runs once per drive cycle when the above conditions are met for 1 second.


    • The control module detects that the sensor did not transition below 200 mV and above 730 mV during the passive test.

    • One of the following tests fail:

    Lean Intrusive Test
    - The control module detects that the sensor is more than 200 mV for 12 seconds.

    - The sensor is less than 200 mV.

    Rich Intrusive Test
    - The control module detects that the sensor is less than 730 mV for 12 seconds.

    - The sensor is more than 730 mV.

    • DTC P2A01 sets within 10 minutes when the above conditions are met.

    All things being equal, the o2 sensor is probably bad. It didn't set a heater code, so the heater side of the o2 is most likely good. You need a scanner to read the 02 sensor and see what is happening, but it's a good bet to be just a bad sensor.
  3. RSSebura

    RSSebura New Member

    Thanks for the info. That is the same info I got from one repair shop. Think I may try replacing the O2 sensors. Will probably replace them with the sensors you dont have to put together, because it appears they used the ones you assemble yourself.
  4. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

    Good luck and let us know how it goes.
  5. RSSebura

    RSSebura New Member

    So I had my oil change today and found out that I have a crack in the driver's side cat... could this cause a double downstream O2 engine light?

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