Yamaha F175, F200, F225 and F250 Diagnostics: Inline Four and V6 by App

Between 175 and 250 hp you'll find two designs: the inline four and the V6. For diagnostics that matters, because the V6 has two cylinder banks, and on ECUs with variable cam timing each bank is monitored separately. M-JET DIAGNOSTIC reads these engines at the diagnostic connector and shows in the iOS or Android app whatever that specific ECU provides.

A wide model range, 18 ECU variants

Covered are the F175 from A to G, the F200 in many versions from A to T, the F225 from A to L, the F235A and the F250 from A to S, each including the counter-rotating FL models. Behind them sit 18 ECU variants. Depending on the variant you get 22 to 57 live values, 12 to 81 fault types and 9 to 16 actuator tests. All 18 support idle learning. So two F200s can look very different in the app, depending on which ECU generation they come from. That means the year the platform was introduced; the build year can be later.

Cam timing per bank

On V6 engines with variable cam timing, the app shows the intake cam angle separately for starboard (S) and port (P). To match, there are two oil control valves, OCV (S) and OCV (P), which you can trigger one at a time with the engine stopped. If the ECU logs irregular cam timing on one bank, the checks are straightforward: run the OCV stationary test, confirm with the shift in neutral that the intake cam angle sits at 10 degrees or less, and inspect the OCV screen. The screen sits in the oil circuit, so put-off oil changes take their toll on it.

Live data you'll see on these engines

• Engine rpm, intake air pressure, atmospheric pressure, ignition timing, injection duration
• Engine temperature, intake air temperature, oil pressure in kPa, thermo switch
• Cooling water pressure and boat speed where fitted
• ETV with TPS1, TPS2 and the ETV relay, plus accelerator position sensors APS1 and APS2
• digital shift with SPS1, SPS2, shift request, neutral detection and shift actuator relay
• Starting battery voltage, and on some engines accessory battery voltage
• Trim sensor, trim relays, starter relay, immobilizer

Testing up to six cylinders one by one

Actuator tests cover the electric fuel pump, the low-pressure pump, the ISC valve on some engines, and the ignition coils and injectors. On the inline four that's cylinders 1 through 4, on the V6 1 through 6. Some ECUs fire them in pairs, 1 and 4, 2 and 5, 3 and 6. Besides the familiar sensors, the fault memory in this class covers cam position sensors per bank, the oil pressure sensor, shift cut-off, the thermo switch, the trim sensor and the long list of ETV, APS and SPS entries from the electronic remote control.

Where the electronics stop

A water pump impeller that has lost vanes only shows up indirectly through temperature or cooling water pressure. Corroded thermostats, cooling passages clogged after saltwater use and lower unit damage are invisible to any ECU. On a V6 that's down on power, I'd read the fault memory first, then compare both cam angles at idle, and only then start thinking about mechanical causes.

Related topics

• Yamaha Outboard Won't Shift: Remote Control, Shift Sensors and Neutral Detection
• Yamaha Outboard Variable Cam Timing (VCT): OCV and Cam Position Sensor
• Yamaha F300, F350 V8 and XTO F375 to F450 Diagnostics by App
• All Yamaha outboard diagnostics topics

Everything runs via app over Bluetooth, for Yamaha outboards with control unit generations from 2003. Learn more about the M-JET DIAGNOSTIC for Yamaha WaveRunner & Outboard.