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Old 06-18-2014, 07:50 PM   #1
steve99
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BRZ 86 FRS ECU Information - ECU Type Flashing Learning Resetting

BRZ 86 FRS ECU Information - ECU Type Flashing Learning Resetting


Disclaimer: This is general information only. I do not guarantee the accuracy of this information. Use at your own risk.


ECU (Engine control Unit) type information SH72531


http://www.renesas.com/products/mpum...7253/index.jsp



http://www.renesas.com/products/mpum...ck_diagram.jsp


How many times can I flash

According to the documentation

Guaranteed flash cycles 1000 , typical cycles before failure 10,000

Programming/erasing control program included as firmware of the ECU itself


What happens when you Flash ROM on an FRZ 86 BRZ

Never have the Engine running or try to start car during a flash or read of the ECU
Never try to read or flash a car with a low weak or suspect battery.

Follow the direction of your programming device.

Sequence to Flash ECU

Programming device tells ECU to go into Program/FLASH mode.

Programming/erasing control program is included as firmware of the ECU, no external Flash voltages need to be applied or diagnostic connectors looped ect. ECU is “flash friendly”.


Communications to other control units in vehicle are shut down (ie body control Unit and Auto Trans control unit ect) This is why you sometimes get CEL codes or CEL light after a flash especially on Auto Transmission cars. (No control unit for Manual transmission cars) these codes are generally related to communication between Engine Ecu and other ECu's in the car ie Body control or you plugged/unplugged your flash device and it interrupted communications. Its best to turn car off before plugging in or removing flash device from car even for logging. These codes that pop up after a flash can generally just be cleared, if they return they need investigating.

Note: the OFT will only display Engine ECU codes, so it possible to get a CEL light and OFT says No Codes, however it should clear the codes.

Programming device tells ECU to ERASE current ROM

Programming device Tells ECU to WRITE new ROM to Flash memory of ECU, data supplied by programming device


ECU will generally remain in “FLASH/Programming” mode till ignition is turned off.

Turn off ignition before you try to start car or obtain engine diagnostics after flashing. Most Programming device software will instruct you to do this anyway.

As the ECU is reset as part of the flash process all the learned ignition and fueling parameters are reset.

The ECU will also perform some diagnostics and calibrations on the VVT cam sensors and throttle position sensors after a reset or flash.

Can Dealer Detect my tune/flash in my ECU

Depends on flash device.

Devices such as Open flash Tablet or Tactrix/Ecuflash do not encrypt or lock the tuned ROM. When you flash back a stock ROM with these devices it is 100% stock.

This means the dealer can connect to car with TechStream (dealer software) and interact with the ECU in the normal manner. even if they pulled your ROM its 100% stock.

Tuning Devices such as EcuTek and BRZEdit have the ability to lock and encrypt the ROM in the ECU and Dealers may not be able to connect/re-flash to interact with the car's ECU in some cases if these locked or encrypted (seed key changed) ROM's are left in the car. If you have the required cables and licenses you can flash a "stock" ROM back to your car but it contains license info which if they were really looking they could detect.

OBD code readers or clearing of OBD diagnostic/CEL codes should still work. The ROM encryption/locking generally only effects the ability to read or write/re-flash the tuned ROM.

Dealers use Techstream software to connect to ECU it can read the ROM calibration ID and various engine parameters but no one has found a "flash Counter" yet.

It possible if they sent your ECU away for analysis or they brought in some super guru in they could detect something but this is unlikely at a standard service.



Minimizing issues and speeding up learning after a Flash or ECU Reset


As the ECU is reset as part of the flash process all the learned ignition and fueling parameters are reset.

The ECU will also perform some diagnostics and calibrations on the VVT cam sensors and throttle position sensors after a reset or flash.


To minimize any issues and speed up learning after a Flash or Reset

  • Turn ignition fully off after a flash or reset
  • Turn ignition fully ON, do not start car, do not touch throttle, leave for 20 sec this will allow ECU to perform its diagnostics and calibrations on cam position and throttle position sensors
  • Turn off ignition
  • Turn on ignition leave for 20 sec then start car do not touch throttle
  • Let car idle for at least a minute (this allows ecu to calibrate cam position settings) and wait till it settles at the normal idle of about 750 RPM, again do not touch throttle.
  • After normal idle is achieved then drive car.
Fuel Trim Learning
To speed up learning of fuel trims you will need to drive smoothly. The ECU only learns fuel trims in “Closed loop “ mode this is during slow or steady throttle movements and cruise and idle. When your driving aggressively on/off throttle and wide open throttle the ECU is in “open loop” fueling mode and does not learn fuel trims, it just applies the fuel trims learned in “closed loop” fueling mode. If the ECU has not had enough learning time in closed loop it will apply incorrect fuel trims and car may feel sluggish or hesitant till it learns.

If your MAF has been scaled correctly hence reducing fuel trims to less than around 2% this learning process is very quick or not needed. Even with stock intake components the MAF scaling can be out by around 8% in places if individual MAF scaling has not been done, more if you have changed intakes and not re-scaled MAF.

Vishnu Reset -Trick
Yes you can google it :-)

Basically it speed's learning of Fuel Trims and will Reset you IAM to 1 if it has dropped due previous knock events (assuming its not knocking at low/steady loads if so you have serious knock problems).

If you do 2 or 3 "vishnu reset" runs ie partial light (20% or so) steady throttle runs from 2000-7000rpm or so in 3rd it will set your fuel trims and reset your IAM (assuming is not knocking at low/steady loads) if its less than 1. The gear is not really important its the partial steady throttle the longer the run the better. A slight uphill grade can be useful (or you can left foot brake). This works anytime to reset IAM back to 1 (assuming its not knocking at light load) it useful when your chasing knock in an area and want IAM back to 1 without an ECU reset.
The idea is to keep ECU in closed loop (learning mode) during this process, when you go WOT it in open loop and does not learn.

What the ECU Fuel Trim and Fine Learning Knock Tables look like

These are for WRX as Learning View not adapted for BRZ/86 yet
BRZEDIT has very good loging ang graphing capabilities and a view similar to learning view below



Bit of further reading if your keen (note its WRX based)

http://www.romraider.com/forum/topic1840.html

http://www.romraider.com/forum/topic5371.html



What if Flash fails

If your flash fails it should not be a problem as the ECU contains the boot and flash control program in firmware of the ECU itself. It should just be a case of telling ECU to erase and flash/write the ROM again.

The small number of “bricked” ECU.on this platform have been due to people using incorrect definition files to edit their rom and then flashing a corrupt rom to the ECU. The corrupt rom generally results in the ecu not being able to communicate with the OBD port. So you cannot erase or re-flash or the ecu continuously resets itself due corrut code . If this happens its going to require specialized knoledge and tools to bring it back to life possibly via Renasas flash utility and SH Boot mode.

The flash process itself is very robust.

Most problems are related to licensing issues with the Programming device or connection issues. The Programming device looses it licensing info or vehicle info and refuse’s to Write the ROM.

If you’re using Tactrix/Ecuflash it does not license or marry up to a vehicle so these problems don’t exist as long as there is not a hardware problem it will write.

EcuTek embeds some license info in the ROM itself so if this is lost due failed flash (remember it erases first) or the dealer overwrites your Ecutek ROM you will need to get your license renewed by Ecutek or your Tuner. Ecutek can also lock ROM’s. Ecutek changes seed key algorythm in ecu so only Ecutek can read or write rom unless a "stock" ecutek rom is written by ecutek. Diagnostic tools should still work.

BRzEdit read locks ECU , dealers or you can reflash with new rom but not read current rom, diagnostic tools should still work.

OFT (Open Flash Tablet) does not lock or encrypt or change seed keys, but it does “marry up” to a vehicle by storing a copy of your original ROM with vehicle VIN and ROM type to stop it being used on multiple vehicles.

Tactrix/Ecuflash – does not lock encrypt change seed keys or marry up to a vehicle, the License for the Ecuflash software is in the Tactrix dongle hardware. It will read/write ROM to any car provided it’s not locked or encrypted by another platform.

Tips to help you avoid Bricking your ECU
http://www.ft86club.com/forums/showthread.php?p=2489551


How to Replace ECU with new or used ECU if your unlucky enough to brick yours
http://www.ft86club.com/forums/showthread.php?t=102810

Resetting ECU

In general resetting the ECU will achieve very little other than resetting any Diagnostic trouble codes and hence CEL light

You better off investigating the cause than just resetting the ECU as you are erasing any diagnostic info.

The ECU continuously learns fueling information and ignition timing corrections so it will accommodate changes in fuel octane rating or 10 % ethanol fuels or minor exhaust/intake changes within its learning limits without a RESET.

Resetting the ECU will just set these back to default, and it will still have to learn, it will learn these changes anyway without a reset and end up at the same point with or without a reset.

Learning is fairly quick usually in minutes, it actually learns quicker if you drive non-aggressively (steady or slow throttle movements) at varied RPM and loads.

You can reset by removing battery cable or ECU fuse for a few seconds.

The ECU is reset if the CEL code has triggered Limp Home mode (low power mode rpm limited to aprox 4000 , base timing A and rich fueling used). When you reset CEL code to bring ECU out of limp home ECU is reset. Not all CEL codes trigger limp home mode.

Remember you will also reset all the learned fueling and ignition advance tables and the ECU will need to relearn these.

Also the ECU will perform initial diagnostics and calibrations of Cam VVT and throttle sensors/actuators after a reset. See above re minimizing issues after flash or reset

ECU Logging-MAF Scaling-Knock Correction-E85 with OpenFlash Tune http://www.ft86club.com/forums/showt...01#post1842501 Flashing - Reset - Learning http://www.ft86club.com/forums/showthread.php?t=68328
Tactrix Ecuflash-Update ROM-Logging http://www.ft86club.com/forums/showthread.php?t=62332
OFT Tips http://www.ft86club.com/forums/showthread.php?t=71157

Last edited by steve99; 04-22-2017 at 07:10 PM.
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