BEWARE 3rd Party OBD Scan Tools!

Discussion in 'Gen 2 Prius Accessories & Modifications' started by KiwiAl, Mar 17, 2014.

  1. KiwiAl

    KiwiAl Junior Member

    Feb 1, 2014
    New Zealand
    2008 Prius
    Hi Guys,

    Just a quick warning to all regarding the use of Multi-Vehicle, Multi-Function OBD Scan & Programming Tools. Probably applies to all models, not just the Gen II, but there doesn't seem to be a General forum.

    Last weekend, I had a new Transponder Key enabled / activated on my 2008 JDM GenII. The programming, which involved 2 phases, first opening and closing the Driver's door multiple times with the original key in and out of the Dash in a specific sequence, which activated the remote, then a second phase requiring a Programming Tool plugged in to the OBD port, and passwords input etc to enable the Transponder, took about 5 minutes. The Programming Unit was a large, almost square, black unit. It had menus for all sorts of car brands and models, but I don't know what make it was.

    All seemed to go smoothly and shortly after, I was on my way. Went, literally, to the next street to visit a friend. After I left, as I slowed down for a speed bump, noticed (just as I got to it), that a bunch of Brake Warning lights had come on.

    The rest of the story of what happened and the followup is on this thread:
    YeeHaar! ABS, Brakes lights, C1203, C1345, | PriusChat

    Today, took the car to my local Toyota Dealer.

    Here's the Worksheet report [sic]:

    Vehicle has fault code.​
    Scanned vehicles system and found fault codes​
    C1203 - Engine control malfunction system communication circuit​
    C1345 - not learning lineor valve effect.​
    Reset vehicles braking system using toyota scan tool and road tested vehicle.​
    No fault codes on dash.​
    Re scanned system and found fault to be rectified.​

    Conclusion by Toyota Dealer / Workshop:

    The 3rd Party Scan Tool caused this fault.

    There was nothing else wrong with the car as far as they could tell, and a 20km Road Test didn't find any more problems. The only potential missing variable is that it was wet on Saturday and fine today.

    Just when I was hoping I might score a new Brake Actuator under warranty. No such luck.

    The moral of the story: Beware; sometimes, fault codes are not reliable, and can be generated by other things - dying 12V Batteries being one of them. I don't know what was wrong and the above report and a little verbal commentary was all I got.

    That said, tonight while driving at 50km/hr on a flat road (almost certainly with the ICE running), had an incident of no acceleration / delayed acceleration on sudden throttle demand. Don't know if this is related, but it's the first time I've ever had that, so wonder if there's something else going on. Maybe this Scan Tool has caused some damage to the OBD / Internal Communications Network. Will have to keep an eye on this.

    One more thing I did get today. During my discussion with the Service Agent about the car and its history, I mentioned the ICE coolant pump replacement. He was surprised to hear that my pump had actually leaked. Apparently, they replace all suspect, dribbling or oozing Coolant Pumps as a matter of course, as a Precautionary Measure. Apparently, Toyota seems to recognise that their early coolant pumps were not up to the mark. I wonder if the replacement pumps are much of an improvement.

  2. AzWxGuy

    AzWxGuy Weather Guy

    May 22, 2011
    Tucson, AZ
    2011 Prius
    I had a similar problem documented in this thread:

    2008 Prius and CAN/OBDII Scan

    As I mentioned, the dealership wanted me to repeat the process to see if it would happen again. As much as I wanted to know myself, and possibly help identify a weakness or fault, I didn't have the time to fool with it. So the problem persists. I could probably cause the problem again if I connected my OBD reader and requested "live" data. That is what did it last time.
  3. ccdisce

    ccdisce Active Member

    Oct 10, 2010
    Stone Mtn GA USA
    2008 Prius
    The use of a Generic Read-them-All type of OBD2 Scanner on the newer cars is not recommended IMHO.
    The OBD2 Port has morphed into a car manufacturer specific DLC Port so much so that pins that were locked to other manufacturers have been appropriated and used to implement added busses such as the A/V bus and the trans-mission bus, body control etc.
    The CAN bus that has been implemented in the Prius supposedly has 7 computers hooked on it , yet when you scan it 3 'full tilt' computers show up. The CAN bus is used as a broadcast bus where the members broadcast information periodically and your scanner can request information if you know the PID and follow protocol.

    If your scanner ever glitches the bus and does not 'buss-off' in time the other members detect this, the CAN protocol calls for everybody to bail out in order to 'heal' the bus. Unfortunately the big boys on the bus will interpret this as a defective bus so the car is now driving 'blind' with around 62 parameters such as VSC activated, Battery Voltage ?? ,Engine Coolant Temperature..........?? not available. So it sets a dagger in the Heart, followed by shutting down the ICE.

    The Scanner CAN Phy device could be defective, Software problem, a ARNIC compliant Phy may help.

    Blitzing a DLC pin with a Programming Vpp voltage from a Programming type of Scanner is not something that I would do lightly.

    AzWxGuy and Robert Holt like this.
  4. depriusoto

    depriusoto Member

    Jul 23, 2007
    Albuquerque, NM
    2002 Prius
    I updated my AutoEnginuity to the latest version 14. When I activated it using my 2009 Prius it threw all sorts of codes in many categories and lit up what looked like all the waring lights! I had installed the program on a different laptop and left the old version 12.2 on another laptop (just in case!). Using that version I was able to clear all the DTCs except for C1203 and C1345. I don't have access to TechStream yet so I can't perform the recalibration that will clear these codes.
    I'm going to talk with AE about this bug and see what they say. I may need a refund...