Gen2 OBD2 app review

Time and again on the forums I see posts concerning members "scanning" their car and getting some codes, or incorrect codes, or no codes. Maybe they have "XYZ" handheld scan device, or "ABC" app with a Bluetooth adapter.

Sometimes I give what advice I can, but realized that I don't really know what some of these apps can do. So I figured why not try a few out on my 2006 Gen2 and report. If I missed something let me know.

Now, the gold standard for scantool functionality is Toyota Techstream, a PC based system used by the dealers to do whatever is needed. Consider it to be a "rolling toolbox" that has everything you need- all the "specialty functions" to scan codes, data, freeze frame, INF (sub) codes, bidirectional controls, resets, system procedures (example- brake bleeding or adding keys), programming, etc.

By that analogy, other pricey scanners might be "toolboxes" as well with most all the same features- while the cheap ones are more like a 50 piece tool set from Harbor Freight. In the same vein, apps are like swiss army knives or Leatherman pocket tools (or cheap knockoff copies)- they are handy and can do a few things (and in a pinch are better than nothing- maybe) but you won't mistake them for "real" tools. They cost less than most scantools and are fairly easy to get setup and running.

I have a couple Bluetooth adapters I use with my Android phone. One is a BAFX Products which is a cheap but functional ELM327 version 1.4 clone. The second is an ODB Link MX+, a pricey "fully functional" adapter that has faster update speeds.

The apps are: Dr Prius, Hybrid Assistant, Torque Pro, Car Scanner Pro, ELM Scan Toyota, OBD Link/OBD Fusion. All except the first two have generic or global OBD2 functions; these are things specifically mandated by the US government for access to the engine computer (ECM). Pending and current codes, mode 06 test results, freezeframe data (a snapshot of engine data when a code was set), status of inspection monitors, "generic" data list. Things that are available (and the same) on most any OBD2 compliant car.

These "generic OBD2" apps also have "enhanced" functionality (usually for a fee) that give added features, such as access to Toyota / Prius specific ecu's for data and codes.

For this test I unplugged some things here and there, got a report from Techstream, then tried out the different apps.
I had unplugged; ICE ignition coil, RF WSS, HV battery safety plug, & battery fan. Techstream gave me: ECM-P0352, Hybrid Ctrl-P0A0D & P3000, HV batt-P0A84, ABS/VSC/Trac-C0200, C1259, & C1310, and A/C B1421 (just because). There was lots of freeze frame data everywhere and much much rejoicing.

First up is Dr Prius. This app is all about basic HV battery data, laid out in a fairly easy to view screen. Block voltage and resistance, battery temps, SOC and amps. The big pain is the autoscaling for voltages- the gap for 0.15V difference can look -OMG- the same as a 1.5V difference.

Menu options let you read or clear ECM and Hybrid control codes -and also HV battery?? I had the P0352, and P0A0D, P3000P0A84 (yes, two codes were glommed together). I swear I have seen threads where people had pulled P3000 with Dr Prius but couldn't get any battery codes.

There are some controls to turn off reverse and seat belt beepers, disable traction control, run the ICE in maintenance mode, and control battery fan. The paid version gives you HV battery "health" test and Life expectancy (approx capacity) test. Also does datalogging.


Second is Hybrid Assistant. This free (android only) app has lots of data on the HV battery, ICE and Hybrid control to let you monitor how you drive. The screen is very "busy" and would take me some time to get used to - has many icons (some of those can open into subscreens). Lots of good stuff- battery power, SOC, ICE fueltrims, temperatures of most everything, regen/friction braking. I think there's a control to turn battery fan on high.

Performing the battery test logs data that the built in Hybrid Reporter renders into a detailed "trip" report with beautiful charts and graphs. My favorite is the graph of block voltages and voltage differential. That's it, data - NO code functions at all. Side note- HA doesn't work with my OBD Link MX+ adapter- somewhere on the site it mentions that there is a problem with OBD Link firmware above a certain version.


Third is Torque Pro. This app has data, performance test, and datalogging based primarily on OBD2 generic ECM data. It has highly customizable data displays. Turning on extra Gen2 Prius PIDs gains you added data for Hybrid control, HV battery, and cruise control. There is a paid Toyota plugin, but that doesn't seem to have anything for Prius?. (I don't recall what was different from the free vs paid versions of Torque). I don't see any added ICE/ECM data, no bidirectional controls, and the only code that came up on a scan was the P0352 in the ECM- nothing from any other ecu.

To me, this app takes lots of time to set up, and "out of the box" doesn't have much code function.


Next is ELMScan Toyota- got this years ago for my Corolla. It's a paid app that has generic OBD2 and enhanced Toyota ECM data (but nothing Gen2 Prius specific), current and historical codes. It can also access Electric Power Steering (EPS), ABS, and I think SRS as well. It showed the P0352, C0200, C1259, and C1310- not all had code descriptions.

This has the only bidirectional ECM control I've seen- it can force fuel trim positive or negative to test Air fuel and oxygen sensor function. (it shows Gen1 Hybrid and HV batt ecu's but nothing Gen2). Some data logging and graphing.


CarScanner Pro is another OBD2 app with Toyota enhanced stuff - it will "scan" for 131 possible ecu's but on my Gen2 it only "found" generic OBD2, the ECM, Hybrid control, and HV battery. (at least it tells you what ecu's it can talk to) Seems like it some "Toyota" ECM data (but not Prius specific), and hybrid/ battery/ cruise control data. It pulled the P0352, P3000, and P0A0D. Not the P0A84. But clearing the hybrid codes did clear the battery code. Says it has some datalogging and graphing. Paid version gets some stuff on mode06 and more(?).


Last is OBDLink and OBDFusion. These are (almost) the same app. Generic OBD2 with paid enhanced access. Access is sold for each make for each model year individually. (2005 Toyota is separate from 2010 Toyota from 2009 Ford, So multiple cars can get pricey quick. OBDLink only works with the OBDLink family of adapters. OBDFusion works with generic adapters, but only has limited functionality with cheaper ELM327 "clones".

I had purchased OBDFusion(and 2006 Toyota access) with the BAFX adapter. On my 2006 Gen2 I could connect to ECM, cruise control, hybrid control, HV battery, ABS, EPS, SRS. (and OCS?- but data was all zeros?) Looked to have data on all of those, including some Prius ECM data like CHST temp and 3-way valve. Shows current, pending, and historical codes- P0352, P0A0D, P3000, P0A84, C0200, C1259, and C1310- all with correct definitions. Only had ECM freeze frame data. No bidirectional controls.

The BAFX adapter wouldn't work (comm error) when I tried to connect to any "secondary" ecu's on the BEAN bus (A/C, TPMS, power control, etc). You apparently need some form of "good" adapter that has genuine ELM327 ver. 2.0 or better.

I later got the MX+ adapter with OBDLink app- fairly pricey, BUT- it presently gives you free access to ALL the enhanced add-ons. All years, all makes available. I see lots of different cars so it's worth it to me. This got me (some) access to the Gen2 secondary ecu's. It looks like codes are available from TPMS, body, gateway, A/C (picked up the B1421), smart key, TCM (parking pawl ecu), immobilizer, power source control. Data- ehh. Some stuff worked- TCM, a few body PIDs, A/C was a static snapshot- not dynamic?, TPMS was useless (no tire pressures or IDs)- other ecu's had zeros for PIDs. Limited- not sure what's going on or what else it can do, but seems overall to have the most coverage of these apps.

So there you go. Each app has it abilities and limits- almost no bidirectional controls- no INF / sub codes- no special tests or functions. Only ECM freeze frame data- if any. Yet each can be useful if you know what they can and can't do.

 

Working on this has helped me puzzle out the Gen2 databus topography. My current understanding (theory) is there's a CAN network, a gateway that connects to the BEAN (looks like a proprietary LIN) and the AVC (infotainment). Then there's the SIL serial network that parallels part of the CAN- this looks like a K-line (ISO9141 or KWP2000). Most intermodule communication uses the CAN/gateway/BEAN as needed(?)- except for SRS (which has SIL and a couple dedicated circuits to the CM and Hybrid control).

Judging how the CarScanner app works vs the wiring diagram- only the ECM, Hybrid control and HV battery talk to a scantool at the DLC (OBD2 port) on CAN. Everything else uses the K-line (and gateway to BEAN) for diagnostic (scantool) communication. I really don't see much about SIL in the service manual.

I'd expect newer cars to be more "CAN-centric" designs which should have improved access.

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Interesting what doesn't make it to the service manual. The observed data matches with the descriptions you posted, but there is NO mention of ISO 9141 anywhere in the service manual- esp. in the multiplexing section.

The SRS section describes the ECU using ISO 15765 (CAN) for communication- but the SRS is nowhere on any network description and there are no CAN circuits in the SRS wiring diagrams. Go figure.

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UPDATE!!!!

So, I saw another forum member that had used a different app and interface... All I can say is

FORGET (almost) EVERYTHING THAT I POSTED ABOVE!

Stop what you are doing and go purchase the Autel MAXI AP200. NOW.

This device (proprietary OBD2 Bluetooth adapter) and app are everything that ALL the other apps are not. It's about 65% of the functionality of a Techstream- that fits in your pocket. Pretty much FULL code and data for ALL systems.
That includes INF codes. Freeze frame. It has has some diagnostic details and tips for some codes. It claims to be able to program TPMS sensor ID', and to perform ABS bleed sequences (but I haven't confirmed that these work).

Keep Dr Prius and HA for quick HV battery monitoring. Keep Torque if you like the funky custom dashboard
displays you can make. Even if you already have Techstream, you really want to get this- for the price its ability is stellar.

I'm going to do another post on this.

 

The Autel Maxi AP200.

This is a diagnostic app that uses a proprietary OBD2 Bluetooth adapter. Buy the adapter. Download and install the app. You have to create an account with Autel and register the adapter (Vehicle Communication Interface - VCI).
After that you can get 1 free car brand to download (I got Toyota- duhh!)- this one brand is "permanent" (no subscription fees for it). Download and install several more "modules" (Diag- Asia, EOBD - generic OBD, Demo, and Toyota). You can buy access to additional brands if you want. Each of these additional brands is a one year subscription that has to be renewed in order to keep functional after that year is up.

Plug in the VCI to the OBD2 port. The app has a VCI manger that will try to scan and connect to the VCI adapter - but it doesn't work at all. I had to manually go into settings on my android phone and pair just like any other adapter.

Start the app and go to Diagnostics- Toyota. You can have it read the VIN, you pick a couple option details, and then scan the car. YES, it will scan ALL systems on a Gen2- and return yes/no for codes on each of the 16 ecu's. Select any given ecu and you can read codes, freeze frame data - WITH INF sub CODES!! Some codes have diagnostic information attached (with a little "i" near it)- code setting criteria and possible causes.



I repeated my test (unplugged a ignition coil, Right Front wheel speed sensor, the HV battery fan, and battery safety plug) just like when I did my app review, and the Autel picked up the P0352, P3000, P0A0D, P0A84, C0200, B1421 (I didn't see the C1259 or C1310- but I didn't run a Techstream scan today).

You can also look a live data for all of the ecu's- not just ECM, hybrid, ABS, HV battery- but TPMS (pressures, temps, and ID codes!), A/C system, SRS and OCS- everything. This capability surpasses ANY other app by far in the DIY arena. While almost any screen can be saved as a pdf file, I don't see any datalogging option. (the only thing I didn't see- ECM has 1 frame in freeze frame data, Techstream shows 5 frames for the code event).

There is a Service option from the main menu. This has "hot function" adaptations and resets that are common across all makes (most don't apply to Prius)- things like electric parking brake retraction, resetting throttle or coding new fuel injectors. It does have options to write new TPMS ID's and also perform brake bleed procedures. I do not know if either of these actually work.

I do not see any other bidirectional controls or configuration options like in Techstream. So this app has most of the codes and data function that is in Techstream, but you can keep it in your car.

For $60-70 plus your smartphone, this can't be beat.

Now I have found out there are different "flavors" of the AP200. There is also the AP200C as well as the AP200H- do not get either of these. These 2 appear to have different subscription bundles that are focused on specific functions (?)- (such as being able to do oil service indicator resets on all makes for a year)- the adcopy ain't too clear on the details.

I still think the "plain jane" AP200 is the best choice for DIY diagnostics as it has all the codes and data on a Gen2, and for the "first" car brand there is no subscription or renewal (you "own" it, not "rent" it).

 

No idea. I can only ASSume that there will be updates from autel through google play or app store like any other app.

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Another option I have found is the ThinkDiag app and OBD2 device by ThinkCar (another Chinese diagnostics company). This is similar to the Autel AP200 in that ThinkDiag is a proprietary OBD bluetooth device and app. Is also a subscription based app. The device is about twice the price of the Autel, but it does more.

It has codes and data on all Gen2 ecu's, freeze frame and INF codes. It also has bidirectional controls, special tests and procedures, the "customize" options menu, datalogging, etc. It appears to have just about every menu item that there is on Techstream (with the exception that it won't do ecu programming). Otherwise it's the whole enchilada. Has about 18 different item in the Gen2 ABS controls menu, including all the bleed procedures. Claims it can add (new) key fobs, or "all keys lost" (reseed) option. I just went into the custom menu and changed some of the default A/C functions (no A/C compressor and no auto fan with defrost) and then set the remote locks to open all doors with 1 press and no chirps.

I can do a compression test, maintenance mode, (even has the useless "charge the HV batt with the non-existent Toyota grid charger" function), test individual dash warning lights, radiator fan on/off, etc. Everything that I can see.

I tried it on a 2017 Gen4- it scanned 30 available ecu's of 32 possible. I could command the ICE water pump on or off. View the recorded 0.02 amp key off draw last cycle. etc- oodles of stuff to look at and do. Also worked fine on a 2013 Gen3 in the shop today.

Don't know if it's just the amazon seller or if others have the same "package", but $130 gets you the device with an activation code and you have use of 15 different car brand software for one year. After that year it's $40 per year for each brand. Pricey (compared to some apps) BUT it seems to be the equivalent to Techstream with less hassle than most of the bootleg versions with their wank mini VCI cables. I'll assume ThinkDiag has similar level of (OE) functionality on other makes.

Download the ThinkDiag+ app. You have to create an account with ThinkCar, register the device serial number and enter the activation code. There's a neat VIN function after you click on the All system Diagnostic button (and there's annoying pop-up adds for other ThinkCar products). Problem is that VIN thing don't work. Scroll down and click on Toyota. Then scroll down and set the area for your car (North America for me). THEN click "16 pin DLC" at the top and it reads the VIN and partially decodes it (you have to enter some options).

Usually the VCI device will automatically connect when you select a main function from the opening menu. Occasionally if I exited a system or cycled the key, I lost comm until I unplugged then replugged the device to reset it.

You can scan the entire system for codes, or just go to a list of ecu's and connect to a particular system. Then you have menu for Codes, freeze frame, actuation, data, and special functions. The codes and data screens can be saved as pdf's (but I had to text them to myself, as for some reason I couldn't just save them to the phone.) You can also record live data, save it and play it back later on the app.

I had no problems with my phone using Android 11. There are complaints that presently, Android 12 and 13 do not function correctly (guess that's a work in progress). The developer says that it does work with ios.

 

The AP200 has codes, data, freezeframe, and INF codes for all ecu's. That's mostly it - "read only" capabilities. The service functions are: writing TPMS ID's, brake bleeding, (and a heading for immobilizer stuff- IDK what that covers).

ThinkDiag has codes, data, freezeframe, INF codes, bidirectional controls, special tests and functions, customize options, datalogging, - for all ecu's - everything that Techstream does seems to be there.

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