2 beeps followed by 3 beeps

[DaddyCrab]

My 2002 140hp Suzuki started recently giving me 2 beeps followed by 3 beeps. It does this when the engine is running or just with the key in the on position but not started. I thought it may just be the oil change reminder needing to be reset. I tried to do that but I still get the 2 beeps followed by 3 beeps. Engine runs fine. About 325 hours on the motor. I am stumped.

[Moonlighter]

Are you getting any flashing codes on the gauge? If so what sequence? Flashing light sequence tells clearer story if there are fault codes.

Meanwhile check battery cables and connections all the way from battery to helm. These engines don't like poor power supply. Symptoms like this can sometimes be due to a bad or corroded connector somewhere in the harness, it's a PITA to check the whole length of the harness but may be the issue.

Also have you checked the engine holder corrosion issue - sometimes the heat escaping from a problem there can damage nearby wiring and set off weird codes. Look at the engine block just near the fresh water flushing attachment and find what looks like a welsh plug there, see if any corrosion has broken thru and allowed exhaust heat to escape and damage wiring. May have to take lower cowling off to see it properly.

[DaddyCrab]

The only thing flashing on the gauge is the "check engine" light. It basically flashes in sequence with the beeping. Flashes twice, then flashes 3 times. And repeats and repeats.. It does this even when engine is not running (and when engine is running as well). Turn the key to on position, and it does this. I cleaned battery cables and checked all connections. Seems ok to me. I will take the lower cowling over this week and check as you suggested.

[Harper]

It's a 2-3 fault code. Inlet air temp sensor. The sensor is either:
1. sending no signal
2. sending an out of range "-46 to +169°C (-114.8 to +336.2°F) (0.10-4.6V)" signal.

You can check it's resistance or voltage readout to test the sensor. I don't have access to a DF140 manual, so don't know for sure which terminals on the connector would apply.

Your ECM puts your motor into a fail safe mode, which will make the engine run pretty close to normal. The ECM is ignoring your IAT sensor and applying a fail safe assumed temperature of 45°C in place of the faulty sensor readout.

It is not a critical situation, and you can run the motor as is for awhile. But for correct, maximum preformance, it will have to be resolved.

[Moonlighter]

Yes Mike is right. Check the ground on the IAT sensor.

[redlowrey]

Check the plug on the air inlet temp sensor, if it looks okay check the sensor voltage, depending on temp it should be under three volts with the key on, it won't flash that code unless the signal voltage is very low under 400mv or high 4.8 volts.

[DaddyCrab]

Thanks, guys. Will check that this coming weekend. Good info!