Codes 23 & 41 BF225

[Mahi-Mike]

Hello,

I have a 04 BF225 that had a water leak started under the cowl on a rough day, and also some waves crashing over the back of the boat. The water leak was from one of the cooling lines. When I throttled the boat to come in the alarm sounded. The next day I tried to run the motor it cranked but would not fire up. I looked into it, and found water all in the vst. I cleaned the vst replaced the fuel filters plugs. The motor started after that and idled smooth. The next time I took it out it idles fine, throttles fine, but I hit 3000rpm I get an alarm. No performance changes when the alarm comes on, and I can throttle past 3k rpm. If I turn the motor off and back on no alarm until the next 3k rpm. I chaeck the codes and it is 23 & 41 . I need some insight on these because I did not have those alarms before the water intrusion.

Did anybody have any similar issues with 23 & 41 ?

Thanks in advance

 

[Fun Times]

About halfway down the following page they offer a fault code chart and 23 and 41 are mentioned...,

Honda Outboard Fault Code List [DTC Chart] |

How do you pull fault codes on a Honda outboard? How do you reset the check engine light on a Honda outboard? Get all the answers!

powersportsguide.com

Honda Outboard Fault Code List

No. of blinks of MIL	Probable problem part
MIL does not come ON or does not blink.	Open circuit in MIL wire Blown MIL bulb Open circuit in ECM ground wire Faulty ECM
MIL stays ON	Short circuit in service check connector wire Short circuit in MIL wire Short circuit in power supply line for ECM Faulty ECM
1	Disconnected oxygen sensor connector Short or open circuit in oxygen sensor wire Faulty oxygen sensor Spark plug misfire
3	Disconnected MAP sensor connector Short or open circuit in MAP sensor wire Faulty MAP sensor
4	Disconnected CKP sensor connector Short or open circuit in CKP sensor wire Faulty CKP sensor
6	Disconnected ECT sensor connector Short or open circuit in ECT sensor wire Faulty ECT sensor
7	Disconnected TP sensor connector Short or open circuit in TP sensor wire Faulty TP sensor
8	Disconnected TDC sensor 1 connector Short or open circuit in TDC sensor 1 wire Faulty TDC sensor 1
10	Disconnected IAT sensor connector Short or open circuit in IAT sensor wire Faulty IAT sensor
13	Disconnected BARO sensor connector Short or open circuit in BARO sensor wire Faulty BARO sensor
14	Disconnected IAC valve connector Short or open circuit in IAC valve wire Faulty IAC valve
21 (BF225A)	Disconnected VTEC solenoid valve connector Short or open circuit in VTEC solenoid valve wire Faulty VTEC solenoid valve
23	Disconnected knock sensor connector Short or open circuit in knock sensor wire Faulty knock sensor
24	Disconnected overheat sensor 1 connector Short or open circuit in overheat sensor 1 wire Faulty overheat sensor 1
25	Disconnected overheat sensor 2 connector Short or open circuit in overheat sensor 2 wire Faulty overheat sensor 2
26	Disconnected oil pressure switch (high pressure side) connector Short or open circuit in oil pressure switch (high pressure side)wire Faulty oil pressure switch (high pressure side)
41	Disconnected oxygen sensor heater circuit connector Short or open circuit in oxygen sensor heater circuit wire Faulty oxygen sensor heater circuit Spark plug misfire
58	Disconnected TDC sensor 2 connector Short or open circuit in TDC sensor 2 wire Faulty TDC sensor 2
7,13	Open circuit in sensor output voltage line (brown/white)
1,6,13,7,10,24,25	Open circuit in sensor ground line (green/red)

 

[Mahi-Mike]

Ok Thanks for the code list.

One other question,

about clearing the codes. I have a MOB kill switch and for me it I cant clear the codes. Is there a trick to clear the codes with a mob kill switch?

 

[jgmo]

You should be able to use the kill switch to clear the codes by holding the lanyard near the clip and then manipulating the kill switch as described below:

Connect the shunting device (technical term for paper clip.)
• Turn on the key switch.
• Pull the safety switch to off, then push to on, then pull to off, then push to on, then pull to off, then
push to on, then pull to off, then push to on, then pull to off. That should be five times off and on and
off within 20 seconds from when you turn the key switch to on. When you get to the fifth time
off...you should hear one or two beeps. The codes are clear. If you did not hear the beeps, try again.
• Turn the key switch off

(Procedure provided by member chawk_man from his Helm Publications authorized shop manual)

 

[chawk_man]

I have not seen or heard of those two codes occurring from the same underlying cause. Follow JGMO's advice - clear codes, then run the engine until it alarms again. Then pull the new codes. Let us know what you get.

If you get codes 23 and 41 again, I can only speculate. It's possible that if the HO2 heater circuit has failed, that could trigger the knock sensor to alarm.

 

[Mahi-Mike]

Ok, I'll let you know. I will be working on it, and testing it this weekend.

I have to check the voltage on the heater circuit. I replaced the o2 and nothing changed. Im also going to check the plugs, to see what they look like, because it says misfire on code 41.

 

[Fun Times]

m also going to check the plugs, to see what they look like, because it says misfire on code 41.

In which a misfiring spark plug or spark plug ignition circuit could cause a knock sensor detection code too… Also if possible when checking spark plugs, maybe try to look inside the spark plug holes with a camera scoop, perform engine compression test, ohms test spark, plug wires, ensure spark on all cylinders to help rule out other possible issues going on.