The Honda PCX / Forza / ADV150 / SH Forums

When resetting the ECU, should you allow the bike to idle for 10 mins? Or do you guys usually hop on and go for a ride? What's the best method?

I just unplug the battery for a minute, and ride it.

Is this using the 'resistor / break into a plug' trick? Can you provide details?

iceman wrote:Is this using the 'resistor / break into a plug' trick? Can you provide details?

What? Simple ecu reset, unplug battery for 30 seconds or more... that's all.

This is however different from the ecu reset wih the factory scan tool in the USB port above the battery.

What ECU PORT??? You mean the 4 pin square connector? It's probably not usb but more or less serial (RS232). Hrmmm.

What ever it is, its the connection port for the Honda scan tool.

Wow, interesting. Will look when I remove my battery tender wires.
I'm just jumping in the middle of this thread so I will blurt out my dummy question. Why would you want to reset the ECU and what does it actually do when it resets. What's does it fix? Does this action reset it to factory (default type) settings like my home computer? Are yas chuckling? That's okay, I'm grinning at me own self too. I am serious though. Sorry for interrupting, but inquiring minds (mine) need to know (learn).
Thank ya

Didn't realise simply disconnecting the battery did a 'soft' reset, I was thinking of the more intricate reset. Searching google for PCX ECU reset found full information and diagrams (not sure if ok to post link to another site)

Ditto to what WhiteNoise said ... and I can laugh at myself too.

In theory when you reset the ECU and let it idle for 10 minutes it lets to computer relearn anything that may have changed. I’d use this procedure for installing exhaust, air pod filter, or anything that could change the way the bike runs. This is how I did it back when I had my zuma, and actually all my Honda cars.

Now for the 4 pin plug near the battery. This is for the Honda DLC computer. This is used to read codes, and other data. I am not sure about the data protocol but I can look more into this tonight. I’m not sure if it has any real purpose for us.

Hear that kram! ECU bro, we got an answer and a quick one at that! Thank you dem0nk1d, that is an excellent response, & one "I" can understand & remember. Such a simple fix to quirks....I'm really liking that!!
Curious about 4pin plug-in, I noticed something similar on my MP3 a few years back and assumed it was for tech use only. Still don't Really know if you happen to find out please share.
I tip my hat to you (o;

Do google for HiDS (Honda Injection Diagnostic System) by Starnics, from Indonesia. Used by Honda dealer there.

Three year old post by one of the legendary PCX whisperers A great one to revisit for all who've modified their engines or exhaust. (Does not apply to transmission of course).

If you unplug the battery it's doubtful it will reset the ECU. If you disconnect your ECU, throttle housing, or have a fault code come up you need to remove the fault code, reset the ECU and throttle position sensor (TPS). If you don't you can get bogus codes and/or lack of performance or not getting advantage of available performance say from a tuning part.

Techno wrote:If you unplug the battery it's doubtful it will reset the ECU. If you disconnect your ECU, throttle housing, or have a fault code come up you need to remove the fault code, reset the ECU and throttle position sensor (TPS). If you don't you can get bogus codes and/or lack of performance or not getting advantage of available performance say from a tuning part.

I believe you left off the part about (idle for 10 minutes with battery disconnected (and or) a ride with the battery disconnected to completely reset the ECU if you don't have the software program.

I don't have a program or a Navpoint cable for the PCX but I do for the Buell. It's true anything not plugged in or functioning when the key is turned on like an air temp sensor will throw a fault code, but it won't be real and I would realize this clearing it with the software. But if I didn't have the software like most of us don't it would clear itself after the 50th turn of the ignition automatically dumping the error code from history. I suspect PCX is similar, no harm done. Error codes are stored for past reference commonly and don't effect performance currently if all is working properly.

Techno maybe I didn't fully understand you. I wish we all had diagnostic software for our scoots. Just last week I experienced engine missing at a specific lower RPM in every gear on the Buell. All kinds of possibilities raced my mind. Fuel pump, spark plugs, ignition coil and the dreaded electrical issue. Plugged the laptop to the bike and ran diagnostics. An error code reported (throttle position sensor short to ground) WHAT! Straight to the sensor on the throttle body tracing the wires back to the harness I found a chaffed wire scratching on the fuel tank. 30 minutes, a piece of electrical tape and a little repositioning of the line and ran like a bat out hell again.

Without this ability I never would have found such an issue. Down for the season or HUGE service charges from Harley would have been my options. I wish at the very least we all had error code plug in dongles for PCX.

You can at least experiment on your car if it has an obds port. Buy a cheap Bluetooth obds transmitter and download torque on your phone.

You can then have extra gauges, accelerometers and run diagnostics. Cheap rainy day fun.

you you wrote:You can at least experiment on your car if it has an obds port. Buy a cheap Bluetooth obds transmitter and download torque on your phone.

You can then have extra gauges, accelerometers and run diagnostics. Cheap rainy day fun.

Then put Torque in HUD mode, throw the phone on the dash and have a cool HUD at night!!
I use my old Nexus 7 as the HUD and it looks great!!

There are motorcycle diagnostic tools for sale, they're not cheap, but I've seen them for as little as $300.

homie wrote:Techno maybe I didn't fully understand you. I wish we all had diagnostic software for our scoots. Just last week I experienced engine missing at a specific lower RPM in every gear on the Buell. All kinds of possibilities raced my mind. Fuel pump, spark plugs, ignition coil and the dreaded electrical issue. Plugged the laptop to the bike and ran diagnostics. An error code reported (throttle position sensor short to ground) WHAT! Straight to the sensor on the throttle body tracing the wires back to the harness I found a chaffed wire scratching on the fuel tank. 30 minutes, a piece of electrical tape and a little repositioning of the line and ran like a bat out hell again.

Without this ability I never would have found such an issue. Down for the season or HUGE service charges from Harley would have been my options. I wish at the very least we all had error code plug in dongles for PCX.

Fault codes should be shown up by the number of flashes to the engine management light or speedo panel, you may have to loop out the inspection plug if you don't have diagnostics unit. Honda/Suzuki/Kawasaki/Yamaha all can be this turns the engine/speedo into a basic code repeater it's then a simple matter of looking on the fault code list. Granted a certain amount of knowledge/skill is required to understand what the code is and where the unit/item is located on the bike.

With Honda (and most others) if you change a part say a throttle body which contains the TPS, the ECU needs to read it or it thinks it's either not there or not set correctly. I the case of an adjustment or up graded part it will be out of range and you will either get rouge codes or the part won't perform to it's full potential. Many systems now "fail to safe" i.e. if they can't read or measure a component crank/cam/TPS they go into a limp mode (get you home) which is an engine map of greatly reduced performance, so you cant damage the engine. This is because they're using closed loop e.g. the ECU has to know what's gone in to measure whats going out, if it can't see the cam or knows the position of the throttle body it can't measure whats going to come out so could fail emissions.

Earlier systems (either basic injection or non injected engines) had open loop and would select an ignition map form the ECU that best suited a given throttle opening/load. These didn't measure the exhaust gases, even though some had oxygen sensors, which really was halfway house to where we are now, it's expensive and forced on manufactures to get through ever tighter emission laws.