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2004 T6 P0040 code Oxygen sensors signals switched

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2004 T6 P0040 code Oxygen sensors signals switched

Post by Joppadad » Sat Jan 13, 2018 9:09 pm

I have searched this forum and did find a relevant post to this issue, but it did not answer my question. 2004 XC90 2.9l is getting code P0040 O2 Sensor Signals Swapped Bank 1 Bank 2 Sensor 1...I know that bank 1 is cylinder 1-3 and then bank 2 is cylinder 4-6, I know where they plug in and here is my question. I know that the turbos have been replaced as I have the paper work, so they MAY have been swapped. What I need to know is which connector the 1-3 bank is supposed to be connected to, the white or the black connector?

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2004 XC90 T6 AWD

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Re: 2004 T6 P0040 code Oxygen sensors signals switched

Post by RickHaleParker » Sat Jan 13, 2018 10:32 pm

Try switching the two, clear codes, see if the P0040 comes back. If it does come back, switch back and start looking for a different cause.

ECM-280C (P0040) Switched front heated oxygen sensors (HO2S). Faulty signal

Diagnostic trouble code (DTC) information ECM-280C

Diagnostic trouble code (DTC) ECM-280C is stored if the engine control module (ECM) detects that both front heated oxygen sensors (HO2S) bank 1 and 2 have been switched (mounted in the incorrect bank of cylinders). The diagnostic trouble codes (DTCs) are diagnosed when the engine has been idling for 10 minutes

Substitute value
  • Long-term fuel trim is switched off
    Three-way catalytic converter (TWC) diagnostics are disabled.
Possible source
  • Faulty signal:
    Front heated oxygen sensors (HO2S) are mounted in the incorrect cylinder banks
    Fuel injection system leakage
    Both the front heated oxygen sensors (HO2S) are defective.
Fault symptoms
  • Malfunction indicator lamp (MIL) lit.

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Re: 2004 T6 P0040 code Oxygen sensors signals switched

Post by FLXC90 » Sun Jan 14, 2018 5:53 pm

Since the connectors are color coded, is it likely that the sensors are installed in the wrong holes? Haven't looked at the routing on mine (ps-they're both dead, so I'll find out soon enough!)

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1998 V70 T5, 112k sat 5 years, still in mechanical coma (for sale )
2004 XC90 T6 AWD: 186k, 60 on transaxle ( traded in today)
1998 POS70 N/A: DD/training aid, 236k but really about 240k, I think...ABS module( passed on to son who sold it)

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