Ongoing P2112 P2103 Codes. This is long...

Discussion in 'Gen 2 Prius Technical Discussion' started by UBA10, Mar 11, 2021.

  1. UBA10

    UBA10 New Member

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    Hello PriusChat. Long time lurker, first time member.

    2008 Prius 121,000KMS
    -Unknown previous maintenance history, But we do know the car was owned by the province.
    -Clean MAF
    -Clean oil and right @ max

    TL;DR
    -Prius has P2112 P2103 intermittantly but P0A0F always.
    -WOT causes care to buck, leading to the ICE shutting off and giving me traction battery only. CEL/ABS/RT lights are on.
    -Throttle actuator and position sensor circuits are good.
    -Swapped with known good ecm and throttle body has not solved my issue.
    -Inspected throttle actuator gears, nothing out of place or broken.
    - All grounds related to this circuit are battery voltage.



    I have a Prius that i have been troubleshooting for almost a month now, and i need some guidance. This car came to me from an auction with drivability issues. I went to pick up the car from auction and drove it home, right as i hit the highway the car started bucking at about 70kph, almost like the car was hitting redline but much much to early. given the unknown nature of the cars previous history i decided to just take it slow the rest of the way home, keeping the revs below 2000rpm to stop the car from bucking.

    Unfortunatly... the car decided it was going to die on me, completely shutting the ICE off and only giving me the traction battery. Thank god i was close enough to get back to the city in time. CEL Brake/ABS lights and Red triangle light are all on.

    Finally got it back to the shop and started looking into the codes. We have 3 codes present in this vehicle: P2112 / P2103 and P0A0F, most of you should be familiar with these codes already, but in our case we do not have all of these codes together at once. Both the p2112 and the p2103 are intermittent and the P0a0F is there always. I was able to clear everything and drive it again to try and duplicate the situation. The car will drive perfect without any issues under normal city driving. Onramp/ Highway driving that may require WOT will cause the car to buck until the CEL/ABS/Red triangle lights come on, shutting off the ICE and only giving me the traction battery. Upon rescanning the car, i have the following: Either P2112 or P2103 (not both) and P0A0F constantly.

    Further investigation using ALLdata we have done the testing outlined by toyota, Check the integrity of the TPS circuit wires, Check the integrity of the Throttle Actuation motor wires, which both passed with no issues. I even went as far as load testing them from the ECM side of the harness to make sure i was getting full voltage through them. A friend of ours has a scrap yard and let us borrow a used throttle body and used ECM for diagnosis, which to my surprise, Neither had any effect on the situation. I have the exact same symptoms with a known good Throttle body and ECM from a running and driving prius with no issues. If the throttle circuit is fine, and the ECM is doing what its supposed to, i must be missing something.. Toyota has really only outlines those 2 circuits as probably causes, along with the throttlebody/ecm.. I've read multiple posts about the plastic piece getting stuck inside the gears of the throttle actuator, but ive taken both apart with no issues. i am stumped and any help is greatly appreciated.
     
  2. SFO

    SFO Senior Member

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  3. UBA10

    UBA10 New Member

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    P0A0F - Engine failed to start

    i have all of the documentation for both those codes, which i outlined in my post.
     
  4. SFO

    SFO Senior Member

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    Which device and or App are you using to retrieve the OBD2 codes (DTCs) outlined above?
     
  5. PriusCamper

    PriusCamper Senior Member

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    Usually people who are dealing with the throttle problem are using an OBD2 code reader that's not designed for hybrid vehicles. keeping a bluetooth OBD2 reader in your glove box and Dr. Prius App on your phone will solve that. Here's buyer's guide: Hybrid battery diagnostic and repair tool for Toyota and Lexus

    Also Toyota Techstream software on a laptop via a mini-VCI plug can do even more than Dr. Prius app.
     
  6. UBA10

    UBA10 New Member

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    We are using an AUTEL MAXYSYS 908SP This is not a cheap autozone scanner. i also have access to my snapon scanner which is of no help in this situation. the AUTEL Gives me much more control than the snap on does.
     
  7. Elektroingenieur

    Elektroingenieur Senior Member

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    If you’ve tried two different replacement ECMs and throttle body assemblies, including a set from a known-working car, and are still getting DTC P2103 or P2112, I’d suspect a fault in the engine wire harness (or connector T2 or E5) that’s intermittent, not detectable with a multimeter, or both.

    DTC P2103 has a fairly specific detection condition (high current in the throttle motor circuit) that strikes me as unlikely to be triggered by a problem elsewhere, but I suppose it might be worth checking the connections between the ECM and body ground points EC and ED, as shown in the Electrical Wiring Diagram.

    The engine wire harness, part number 82121-47080, is shown in this illustration from catalog Figure 82-02, Wiring & Clamp.
     
  8. SFO

    SFO Senior Member

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    Many here (and DIYers) will use Techstream (toyota dealership technician software) when diagnosing, troubleshooting or repairing.
    Maybe the catchphrase "Freeze Frame Data" ?
     
  9. UBA10

    UBA10 New Member

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    We have been testing the wiring harness thoroughly, and our body grounds which seems to be normal, giving battery voltage. I was wondering that maybe during WOT the harness is being pinched in a spot causing our problem, because stationary all our TPS and TMA are all functioning within proper values, and im able to actuate the motor fully with my power probe. We do not have access to a techstream unfortunately, will also report back with some ffd soon.