I have a 2014 FA2 TRX420. My problem is that the dash is flashing constantly under gear selector. There is no code to it. Just a never ending flashing dash. When I unhook the ecu nothing changes. It will turn over with the starter but no fire or fuel. A new shift angle sensor and angle bank sensor have been installed with no changes. Was getting dtc's from power steering but cleared them. Bought machine as is. Not running. I like challenges but this is wearing me down. Don't know of any other people near me with the same machine to swap ECU's. Any suggestions?
Trx420 ecu
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I haven't looked anything up in the service manual yet, but it sounds to me like the display is not communicating with the ECU or anything else. Since the history of this 420 is unknown to you it might be a good idea to verify first that it has the correct display, harnesses and ECU on it and then begin to troubleshoot their connections to each other. The wiring harnesses and connectors must be undamaged. The connectors must be clean with no bent or dirty/corroded pins. The frame grounds from the harnesses must be clean and tight, etc.
You'll have to take the plastics off while you work on it and you'll need a decent quality multimeter. Use the service manual for reference and begin to check for continuity in the power, ground and data lines between the ECU and display. It may be as simple as a bad connection in a plug or it could be much worse. Once you find it the display and ECU should begin to communicate with each other and some basic functionality should return. Only then will you be able to begin a more thorough diagnosis of any preexisting faults.
Hopefully the ECU has not become damaged or voltage spiked yet. Always turn the key off before you disconnect or reconnect any plugs or components under test to avoid spiking the ECU.
Welcome to the forums!
You'll have to take the plastics off while you work on it and you'll need a decent quality multimeter. Use the service manual for reference and begin to check for continuity in the power, ground and data lines between the ECU and display. It may be as simple as a bad connection in a plug or it could be much worse. Once you find it the display and ECU should begin to communicate with each other and some basic functionality should return. Only then will you be able to begin a more thorough diagnosis of any preexisting faults.
Hopefully the ECU has not become damaged or voltage spiked yet. Always turn the key off before you disconnect or reconnect any plugs or components under test to avoid spiking the ECU.
Welcome to the forums!
Thanks for your reply retro.
I have totally stripped the machine down and repainted the frame. Replaced gear shift shaft as someone had pulled out on it causing it to become disconnected from shift drum. While disconnected they tried to turn the shaft causing the end that the tool attaches to to break off. While it was apart I replaced all the o rings gasket and clutches. I found and repaired 4 breaks in the gear position sensor wires. I have the proper service repair manual an have checked connections for the gear position sensor, shift angle sensor, shift solenoids, Reverse switch, gear changing switches, eot sensor right to the ecu plug. I'll check display next. Fuel level display works fine as well as mileage indicator and service indicator and mil ps etc.
Machine has 5500 miles on it. Looks like hard miles according the the condition of the Plastics which are all off and all need to be replaced. Good job I like challenges. That's getting a little old though. Lol
I have totally stripped the machine down and repainted the frame. Replaced gear shift shaft as someone had pulled out on it causing it to become disconnected from shift drum. While disconnected they tried to turn the shaft causing the end that the tool attaches to to break off. While it was apart I replaced all the o rings gasket and clutches. I found and repaired 4 breaks in the gear position sensor wires. I have the proper service repair manual an have checked connections for the gear position sensor, shift angle sensor, shift solenoids, Reverse switch, gear changing switches, eot sensor right to the ecu plug. I'll check display next. Fuel level display works fine as well as mileage indicator and service indicator and mil ps etc.
Machine has 5500 miles on it. Looks like hard miles according the the condition of the Plastics which are all off and all need to be replaced. Good job I like challenges. That's getting a little old though. Lol
Check the service manual on this to make sure I'm not giving bad advice... but if I remember correctly the ECU needs to be initialized after certain diagnostic procedures or component replacements? If that applies to your bike then the initialization procedure is explained in the service manual. Initializing the system can provide helpful diagnostic clues even if it doesn't fix anything, because if there are wiring or connection issues somewhere the initialization procedure will fail to complete, as explained in the FSM.
Project has been on hold for a bit. I guess while working on it I inadvertently left the key on. Next time I went out to it, it was totally dead. No life at all. Battery was still at full charge. Checked fuses. Main 10 amp fuse was dead. Must have blown a dozen more trying to troubleshoot and find the problem. Would not blow any fuses if the gray connector on the.ecu was unplugged. Went to service manual and was tracing wires looking for a short. Came to the coil wire and was about to trace it and saw melted plastic dripping from the coil. Thank god for the fuse or I would be short a garage and garage full of tools , my Harley, not to mention my beer fridge. Lol So now I'm waiting on a new coil. Honda changed a lot of parts in the 2014 model year and only 2014 or newer parts will fit. Lucky me. NOT. No 2014 or newer parts used available near me. Now it's hurry up and wait. Guess I'll have to go to the garage sit on the chair enjoy a beer while shaking my head and asking myself "What the hell did I get myself into". Haha
Received new coil. Still have all the same problems however now I take the key out. Lol. Another issue I noticed is when the key is turned on the temperature c———h flashes constantly leading me to wonder if the bike has a shut down for fuel and spark in overheating conditions. Next thing is what can cause it to think it’s overheating
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If the temp sensor wire is grounded (or the sensor is shorted) the overheat light will come on and the ignition/fuel will be shut down by the control unit. There are specs for testing the sensor in the manual. Its beginning to sound like you got wiring harness problems..?
New computer from Partzilla landed last Friday. I was Working until today so I decided to give it a try. Well. Disconnected the battery plugged it in. Almost got down and said a prayer. No not me. Reconnected the battery crossed my fingers and toes. Turned the key on. Fuel pump iniated for the first time. That was a plus. Waited on the speedo to finish its thing. I had a N nothing flashing. Cool. Wound her over. Nothing. Gave it throttle wound it again. Hiccuped. Let the throttle go. She fired up for the first time since I bought it. Quit very shortly after though. Tried again started and stayed running. I almost kissed it. Lol. Took it for a couple mile ride. -11 c out. Working like a dream. What a relief. So now I need to find the money to order plastics for it as original one are trashed. Thanks for the suggestions on getting it going. I am a persistent bugger. A year in 2 weeks time.
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Hey, congrats! I love happy endings!
Keep the fuel fresh in 'er, those fuel pumps are chintzy and don't last very long in rotting fuel. Especially in ethanol, don't ever put any of that scam in the tank.
I'm looking forward to pics after you get new plastics!
Keep the fuel fresh in 'er, those fuel pumps are chintzy and don't last very long in rotting fuel. Especially in ethanol, don't ever put any of that scam in the tank.
I'm looking forward to pics after you get new plastics!
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