Two owners post a fault code, each swears the list in a favorite thread is right, and they name different parts. Both can be correct. Yamaha four-strokes from 2002 to today use two generations of control unit with different numbering, and a list copied from one into a thread about the other turns into nonsense. Add display codes versus diagnostic codes and lists written for another model year, and you get threads that never agree.
Two generations, two numbering schemes
Generation A covers the early skis: the FX140 and FX1000 of 2002 to 2005, the FX1000(A) and FX1100 up to 2008, the FX HO MR-1, and the GP1300R of 2003 to 2008. Generation B starts with the VX1100 in 2005 and includes everything newer: the VXR and VXS, the 1.8-litre FX HO, FZR and FZS, the SVHO models, the GP1800, the three-cylinder VX, EX, SuperJet and JetBlaster, and the 1.9-litre skis from 2024.
The same number can name different parts on the two. A few that trip people up:
- Code 24 is the throttle position sensor on generation A and the camshaft sensor on generation B.
- Code 19 is the pulser coil on generation A and battery voltage on generation B, where the pulser coil is code 13.
- Engine temperature is code 21 on generation A and 15 on generation B.
- Intake air temperature is code 35 on generation A and 23 on generation B.
- Code 41 is air pressure on generation A. On the 1.9-litre skis of 2024 and later the same number is a thermo sensor message.
Anyone reading a list for the wrong generation ends up replacing a part that has nothing to do with the problem.
The TPS example
One forum gives code 18 for the throttle position sensor of an FX HO. The diagnostic database of the control units lists 24 for the throttle position sensor on the early generation. That doesn't mean one of the two is lying. Dash displays, manuals and diagnostic readouts don't always use the same numbers, and a number remembered from a different model year gets copied from thread to thread until nobody knows where it came from. It is also why lists here come with a warning: numbers can differ, the description is what you act on.
How to know which list applies to you
Go by model and year, not by engine size alone. A ski from the MR-1 era before 2005 or a GP1300R is generation A. Anything with electronic throttle codes in the 112 to 145 range, which starts with the VX1100, is generation B. The code count is another hint: the FX140 has only about 8 to 12 codes, while generation B skis run from roughly 39 up to 50.
The M-JET Diagnostic sidesteps the whole problem by identifying the model itself and printing the code together with a plain-text description, a possible cause and test steps. It supports 37 Yamaha four-stroke models from 2002 on, which covers both generations. When a forum number and the app description disagree, go with the app.
Where a description won't settle it
A description tells you which circuit or sensor the control unit is unhappy with. It doesn't tell you why. A temperature sensor code may come from the sensor, from its connector or from a real heat problem, and a code can't replace a look at the part. If two sources disagree, read the live value of the sensor named in the description and see whether it is plausible.
The generation A numbers are listed on the page for FX140 fault codes, and generation B has a list per model family. Identify your generation first, match the description, and buy parts after that.
