All 4 Oxygen Sensors are suddenly bad... | FerrariChat
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All 4 Oxygen Sensors are suddenly bad...

Discussion in '348/355' started by Craig Atkins, May 20, 2018.

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  1. Craig Atkins

    Craig Atkins Rookie

    May 1, 2018
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    Craig Atkins
    #1 Craig Atkins, May 20, 2018
    Hi Everyone,
    I've got trouble codes on all of my oxygen sensors (low voltage) and two codes (P1127 and P1129) I haven't been able to chase down. Car runs poorly and will eventually die out. I'm thinking something upstream of the oxygen sensors has fried them. Anyone have thoughts or experience with something like this? Thanks, Craig
     
  2. Craig Atkins

    Craig Atkins Rookie

    May 1, 2018
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    #2 Craig Atkins, May 20, 2018
     
  3. Craig Atkins

    Craig Atkins Rookie

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    #3 Craig Atkins, May 20, 2018
    This is for a 1997 F355
     
  4. INRange

    INRange F1 World Champ
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    #4 INRange, May 20, 2018
    Craig,

    Welcome. There clearly is more to this story than the codes spontaneously showing up on all the O2 sensors. Was there any major work done to the car recently?
     
  5. Craig Atkins

    Craig Atkins Rookie

    May 1, 2018
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    Craig Atkins
    #5 Craig Atkins, May 20, 2018
    I purchased the car about a month ago (400 miles), and according to the mechanic for the prior owner, there was no major work done. He mentioned a check engine light issue and addressed it by adding a ground wire to the alternator. I found a ground wire hose clamped on to one of the oxygen sensors. The oxygen sensors look pretty new, so I'm thinking they've been recently replaced. I've checked all connections, fuses, relays, ECU, etc. The Bosch part number on the O2 sensors I have is 309 2031. Anyone know if this correct?
     
  6. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
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    #6 AceMaster, May 20, 2018
  7. taz355

    taz355 F1 Veteran
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    #7 taz355, May 20, 2018
    what kind of headers
    What exhaust
    Is exhaust valve original
    are cats original
    Does sec air pump work
    Any other mods to the exhaust or engine
    Any thing bypassed or altered from original we need to know about
     
  8. taz355

    taz355 F1 Veteran
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    #8 taz355, May 20, 2018
    Last edited: May 20, 2018
    No
    Corrct fo the 5.2
    Bosch 13819 pre
    Bisch 13820 post
    Full part number is
    0258003819
    0258003820
     
  9. taz355

    taz355 F1 Veteran
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    #9 taz355, May 20, 2018
    Rock,auto,has them search 13819 and 20
     
  10. Qavion

    Qavion F1 World Champ
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    #10 Qavion, May 21, 2018
    Last edited: May 21, 2018
    I've been trying to find a common power source for the oxygen sensors, but my references appear to have conflicting data. No one seems to have an official diagram for the 5.2 engine management system, apart from a pre-production Bosch diagram and some FChat pinout tables (which don't always match the Bosch diagram).

    According to the Bosch diagram, the voltage for the four 5.2 O2 sensors is supplied by the Motronics ECU [pin 46] via splices. This voltage goes through each O2 sensor and is returned on four separate wires to the ECU. If all four O2 sensors are showing low voltage, there might be something wrong with the voltage being supplied by the ECU, or the wiring to the splices is faulty.

    O2 heater voltages come from a common source, too, but these fault codes you are getting would specify an O2 heat problem.

    Anyway, if you decide to do wiring checks at some point, look for bent or contaminated pins on the Motronics ECU .. and damaged wiring (especially where it goes through the bulkhead).
     
  11. johnk...

    johnk... F1 World Champ
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    #11 johnk..., May 21, 2018
    Low voltage error means the O2 sensor is reporting an excessively low voltage signal to the ECU. This can be either a problem with the sensor or that the mixture is too lean. Since all 4 of you sensors are reporting this error, and the car dies, I would suggest that you might have a fuel delivery problem. Could be any of several things but you might start be checking fuel pressure.
     
  12. Qavion

    Qavion F1 World Champ
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    #12 Qavion, May 21, 2018
    Yes, this is pretty common. I have this setup on all my O2 sensors. Apparently the OEM wiring doesn't provide a very good ground, so additional grounds have been added.
     
  13. AceMaster

    AceMaster Three Time F1 World Champ

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    #13 AceMaster, May 21, 2018
    My apologies I didn't realize this was a 355, the link I posted was for 348
     

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