Mercruiser Fault Codes??
 

Seems like fault codes are a black box? Well guess they really are! and I'm having trouble determining if some or all of these really apply. I have twin 8.1 L Mercs and the codes I get don't seem to make sense unless the ECMT is failing and throwing bad codes? Any thoughts....Faults shown are:
94 Pitot Pressure Circuit Low
75 Fuel Level 1 Circuit High
118 Steering Position circuit high
191 Fuel level 2 circuit high
179 Starboard ECMT Overheat..

any comments appreciated!

All of those codes look normal except for the last one. Not sure what that is.

Yes and no about normal codes. Depending on your 8.1 app. Do you have smartcraft gauges - do have DTS - do have a catalyst 496 . Would need to know serial numbers of your motors to determine what you have as far as the 8.1. I will say this again and again anytime you take your boat in for service or buy parts from a OEM dealer the first thing they need to know is what is the serial # of the engines. Why because a 2001 496 is totally different set up than a 2010 496. Serial number breaks determine as were parts have change and different setups of that same engine. This holds true for all marine engines.

With that said I can not speak 100 % if your codes are normal or not for the first 4 codes not knowing exactly how your 496's are set up exactly from the factory or boatbuilder. Anyways most of the times on a standard 496 especially the earlier models without DTS (digital throttle & shift) these codes are meaning less.

CODE 179 Starboard EMCT - is Starboard exhaust manifold temperature HIGH. Could be sensor or a cooling problem.

I am marine factory OEM trained now for 25 years. Just in case any needs to know where my logic comes from.



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BUP, I have a question if you don't mind. Have twin 2003 6.2 mX's with SmartCraft.. Ran flawlessly up to 200hrs,,got around 240hrs now with an annoying warning 'overspeed throttle back' massage on the port engine only.Water pressure, water temp, oil pressure all indicate identical on both SmartCraft gauges Tried swapping the ECM 555's and the problem stays with the port engine.Have the cool fuel system. I removed the small s/s filter already in the regulator because it seemed to be clogged up and raised fuel pressure close to 70 on the Schrader valve.Fuel pressure is fine now but still get the warning intermittently.Swapped the water pressure sensors on the PS coolers,,didn't make a difference.Last thing I have yet to try is swapping the oil pressure sensors [ not the sending unit since it sends the right readings to the SmartCraft gauge and the backup gauges I have for all functions] and see if that causing the problem. Oh,,and tried swapping the drive lube monitor bottles too thinking the float inside may have got stock on the bottom sending false low lubricant level.
I have the Rinda scanner and it records the same message of overspeed. Thanks

R U saying just an Overspeed code ? the jist

your recommended rpm range is above what is recommended for your app
are you getting a beep beep or a warning horn ?
If so here some added info after beep or horn.

Cylinders stop firing next typically will have a fault set of overspeed 1 (meaning level 1 overspeed) in which will or can cause the power to be limited but especially will reduce power if you reach level 2 - Overspeed 2 code.. Guardian mode

some causes of these overspeed codes / faults,

too high rpms
too much trim
too much prop vent
prop hub slippling / cracked hub / or if rubber hub - worn - slipping
engine coupler slip / worn
also too much throttle reving in neutral
also too much throttle by far when running on the water hose / unloaded - whether in neutral or in gear

HOPE THIS HELPS Have to run for the day. Good luck

Bup, the rev limiter in the ECM is set at 5150. My WOT is dead on 5000rpm with Bravo1 26P props.This problem came out of the blue two years ago while cruising around 4000.No prop slip [solid hub] over revving or coupler problems. I can stay on the sticks WOT for a minute or two before the warning comes on.If I stay below 42-4300 I can cruise all day long.Pretty much do everything on my boat, can lift the engines out in a jiffy to do service but this just stumped me. May have to drag it down to my friend's shop, he has the complete Mercruiser diagnostic equipment that tells more than the Rinda scanner.I think one of the 64 monitoring functions in the ECM555 did me in,LOL Thanks for the quick reply.

Thanks for your help!
 

Just a quick thank you to all who responded, you all have a wealth of experience and your willingness to share is awesome.....I do the same in areas I know well...but this isn't one of them so really appreciate your input!

Sounds like BUP knows what he is talking about.

These are the codes that always showed up on my 496HO, no smartcraft, no DTS, 2005 model.

3. TROUBLE CODE STATUS

Current ECM Codes

Sensor Fault, click Read Fault button for details

Trouble Code List:
PITOT CKT LO Code is active
FUEL LVL CKT HI Code is active
STEER CKT HI Code is active
TRIM CKT LO Code is active
FUEL LVL2 CKT H Code is active

as far as these faults always showing up, here is why, fuel lvl2 ckt h in which means if you had 2 gas tanks then you have a real active code for some reason.

Since you do not have a second gas tank nor the sensor nor a connected harness for it, the ecm will record and store these codes by default. These faults can be totally ignored if these sensors are not installed and or a connected harness to that app.

All DTS apps will have steering angles (STEER CKT HI) without DTS this code is defaulted by the ECM so it will show up. Again if you do not have DTS then there is no connection nor a sensor for STEER CKT HI.

Anyways just making a point to as why you see these faults for a lot MPI engines with PCM / ECM 555. Anyways not to go into great details about it - I hope this helps.

SO if I remember correctly a MCM 6.2 MX in which MCM models are sterndrives the rpm range is 4800 to 5200 at full throttle.

The MIE 6.2 for inboards that would be MX 6.2 inboard and the MX 6.2 Horizon inboard models the rpm range is 4600 to 5000. Anyways I would swap your smartcraft gauges or the connections (if possible) and see if the overspeed message follows.

Thanks BUP. First ,I'll wait and see if the oil pressure sensor swap do anything, then I'll swap the SC gauges.Swapping the ECM555's previously didn't make a difference, hoping that maybe the SC swap brings some results.

Hello ! We own an Epic V23 boat that has a mercruiser 8.1 motor.
Apparently no one can help me .. Ive called multiple people in multiple locations.
I found this forum doing research.

When I hook up the computer the error codes I get are the following

Fuel LVL2 CKT H
5VDC pwr 2 L

We have been trying to get this boat to work for 3 months!!!!!!!!!! and Ive had it, i need to figure it out. Can someone pleaseeee help me??!

The boat starts fine, when we take it out as soon as we go over 3300 RPMs the alarm stays on until we go back to neutral. The message on the screen says "Sensor power supply voltage is low" when I select more I get . STBD system failure 217.

Is it possible for you to guide me ? Thanks in advance

I see your post and responded to the same in another section up here. One post we will see it just give it sometime. Heck we all have jobs I think ? Trying to be funny.

2010 350 MAG MPI DTS with emission control
 

I've been to 2 mechanics, have spoken with 4. Smartcraft giving me a STBD fault code 19. Hooked up the Mercruiser G3 scanner. Saw fault codes 219 and 315. Everything is fine per G3 and mechanic. Smartcraft continues to have system fault STBD 19, even after clearing codes. 2 mechanics suggested replacing the STBD O2 sensor post Catalyst. I did, still getting the same smartcraft STBD error code 19.

Any ideas?

Check with it on a scanner, make sure ECM does not think engine is in neutral, had that happen on my old 6.2 boat. Switch throttle cable were it mounts to exhaust was cracked.

Spec Only says he checked it with Diacom and has overspeed showing on the scan as well.

question is do you have the shift in gear switch ? If so that could be your problem. If so it will be located on the shift plate.

If you do not have it make sure you check both engines for it. Just saying as if one engine has it and the other does not ? 2003 I believe all smallblocks should of have the shift in gear switch. Possible swap over if both engines have it to see if problems follows or stays. next possible could be crank sensor and again as said before swap tachs if none of this fixes your problem. I would clear the code and see if it comes backs and or follows especially swapping the tachs over.

Do have any other fault codes in the scan - look into history for any other faults.

POST # 14 how much training do these mechanics have with Mercruiser PCM 09 Cayalyst operation, faults, data fields- CDS G3 Live data , OBD -M 1 faults OBD-M 2 faults. Have to ask because this controller system / catalyst operation is a whole completely different animal compared to ECM 555 & PCM 555 plus the scanning knowledge along with the indepth of it ?.

You know you have 4 - 02 sensors ? 2 - 02 sensors per side - a pre cat 02 sensor and another one after the cat


CDS G3 fault code # 315 is starboard catalyst failed diagnostic test and the catalyst might be DEFECTIVE. They (mechanics) will have to check the live data screen to see the reason why for this code and if that is a failed catalyst for sure or a related problem. Just saying A real defective catalyst can cause engine damage so I am asking how well or NOT well is your engine running ?

FYI - Fault code # 316 is precatalyst 02 sensor B failed rich to lean response time. Have to check Live data screen for this code to for the reason and can be a defective pre cat 02 sensor.

fault code # 19 guardian overspeed - this probably is because of the of fault code 315 as it could possible mean the engine is going faster than guardian currently thinks it should. More detailed info about this is engine rpm is exceeding guardian rpm limit at time of the a real fault.

Thanks much for the information. I'm beginning to realize many mechanics don't know a lot about the newer emission control systems on boats. Aware of the 4 sensors. Was told by 2 mechanics it was down stream O2 Starboard side, whether a bad sensor, bad wires, bad something, but that it was the O2 sensor. Guardian fault code word for word is, "STBD system fault 19 Catalyst. Catalyst is not working properly. Emission control problem. Service engine soon." Per mechanic engine is running good. No issues. All other readings good. I think boat sat for most of this spring, summer. Thinking maybe it is just dirtied up? Not sure, will have to take to a third shop to see if they can figure it out.

Location as in where are you and boat located ?

Have you ran the boat out of gas - running hard any form of misfiring and or low fuel level or the engine runs out of fuel will blow a hole in the catalyst sub strake. FYI.

Misfires are really bad for CAT engines overtime.

Also cat could be restricted

also their is a test port in the exhaust to test reading of the exhaust emissions. You can stick a real wide band hand held in the exhaust access port hole and see what the air / fuel ratio is to. Just saying

You have to ask the techs how much CAT and PCM 09 / OBD factory training they have. Find one that is current. I am very current just saying

Sodus NY

Not run out of gas. Was running 30-40 when I noticed alarm come on.

Guessing restricted flow, but really don't know. My logic is the boat sat most of this year. Had 70 hours on it. I ran it for 3 staright days and on third day it alarmed. Maybe some cataclean through it. If that doesn't clean it up, on to the next step.

Come on up to Lake Ontario! You sound very current on OBD. Need to find one that is up here. Seems like most are not too familiar. Engine serial number: OW987782

Truly appreciate your responses. Good knowledge and have learned more on line, than in reality. If you know the CAT guru up this way, let me know. Otherwise I'll have to part with 12 of my best friends named benjamin for a new CAT and an install.

Michael

I have to back up here as I could not remember what in the hell fault code 219 was. Basically I kind of thought since the your mechanics blew it off it was just something not to worry about as they cleared and or fixed it. Not sure here any of their thoughts or actions. just saying

Anyways thought about it so here it goes. Your overspeed most likely is from this fault code 219. this code is the electronic shift control = ESC - so the PCM is sending out commands for the ESC to move positions but the position sensor is not confirming any of it so the PCM can not find the position of the ESC. Hence the fault code 219.

the ESC is also called the shift actuator in which is a small electric motor to move a shaft that puts the engine / outdrive or if a transmission app in Forward or reverse or Neutral as inputs from the electronic remote control via the command module and the PCM. Also the ERC = electronic remote control send the throttle inputs electronically as well to the engine via the command module and PCM. FYI. and this is all part of DTS = Digital throttle shift and PCM 09 calibrations.

You need to find a current certified Merc & mercruiser dealer and request the Merc area rep to help aid with the diagnostics and repairing of your app correctly and properly. the Merc area should be able to assist with the current OEM dealer. Just saying

hell I was just up to Buffalo for the run.

Thanks for the info again much more knowledge than any other mechanic around. I'm debating going to tech class and learn the engine inside out as no one seems to have the latest knowledge base locally. I found a manual on line that had the 219 and it is as you described. Will have to research some more on tweaking it. If I recall it will reduce the power by 5% until configured properly. With beer in hand and staring at the CAT yesterday I decided to remove the pre CAT O2 and replace with the post CAT O2 that was leftover after I put the new O2 in post CAT. Pre CAT O2 was in worse shape than the post CAT O2. Started the boat and still got the alarm. Went out for a cruise and on way back in noticed the alarm had cleared. Went out again and no alarm. 1 down, 1 to go. Appreciate your feedback.

Can not believe the service manual is online. Merc has been trying to get rid of all this little by little online service info as it really is copy right infringement as well. Anyways kind of not fair for the dealers who have to spend thousands for special tools and manuals and so on when a person or a do it your selfer who basically spends nothing has it at there finger tips for free. Just saying as we all like free stuff including myself.

Currently and coming within a year max - the 02 sensors pre and post are not the same. Post (rear) CAT 02 sensors are now real wideband 02 sensors. Your app being an older CAT app all 4 - 02 sensors are the exact same . just some added info

It is very important that the CAT and its space within maintains the correct amount heat on both ends - not too cold nor not too hot. For the CAT to work correctly it needs heat of 600 min to 800 degrees. With that said engine cooling is now more important than ever.

Make sure your check balls or check valves - one for each manifold and one for each riser (located in bottom of each) are not restricted nor stuck or broken apart. Also make sure the poppet valve is the same and working correctly.

Thanks again. Will check it out.

I have exactly the same prob: stbd system fault 217! What can I do?Thank you

" What can I do " ^^^^^ bring me your boat so I can fix it properly and make some money . Heck its winter and I'm almost caught up with boats.

Have no idea what app and year model and engine serial number here. plus the set up and is this a stock app ? Im not throwing darts and do not want to go thru guess work without any of that info. Sorry man hopefully understandable.

Merc 5.7
 

We bought a 2012 Sea Ray Sundeck 240 with a Mercruiser 5.7 Bravo. Since we bought it we are getting a code 48 stbd exhaust oxygen sensor not working properly. We had our mechanic replace the precat sensor and reset the code. 2 hours later we got the same code so he replaced the post cat sensor. Not even an hour into that we got another code 48 and now are getting a code 50 as well. Any thoughts? We are extremely frustrated. Thank you.

^^^^^^^^^^^ In this thread I Posted alot info here to help out catalyst engine boat owners. My experience one I am trained indepth on Marine catalyst systems, 2 is Cat engines are not for everyone to work on especially with no experience. I see more boat owners and incompetent service shops cause more harm than good and in return really causes huge expense to get systems fixed correctly after the fact.

Two - I hate when I spend my time to offer very solid indepth FREE info that I had to pay for to gain and that person never comes back up to say it fixed it or not. They disappear once they get what they want for info like the poster above. The dude made 5 total posts here on OSO but failed to comeback up for the 6 post to give updates. Anyways --- you need to post your engine serial number - hours on the engines and was the shop that work on your app competent ? Also is your app totally stock ? and is your exhaust totally stock ? do you have captain call exhaust ? meaning switchable exhaust -

I would be more than happy to take the boat to you for repair but I am located in Pennsylvania and I believe you are in the southwest from what I have read. I will have to go down to look at the serial number as I dont have it here with me. In answer to your other questions, It is a stock motor, 160 hours, our mechanic is a Mercruiser mechanic who seems to be competent? but unfortunately, we do not have a lot of boat mechanics around here to choose from. It is not a switchable exhaust. It is a 5.7, 350 Bravo, Mercruiser engine. Ill try to get you the serial number today but we are suppose to get storms so I dont know if that will happen. I'd be happy to report back to you with what happened. I have no problem with that at all. I appreciate any help you can give. Thank you

I understand that you are not close as if you were mostly likely you would called or some how the path would have crossed for your issues maybe in my hands. Just like its does for the 496 marine apps. Seems like that crowd always finds me or I find them. Just had a guy from Kansas bring me his boat with a 496. He basically was stuck with not getting his boat fixed correctly and got tired of parts changing and spending money. Anyways.

You will have to give me your engine serial numbers. There could be updates and service bulletins and so forth that never got done and or needs to be done as engine serial numbers determine all that plus your stock OEM set up. Did you buy this boat new or used - what kind of water did it boat in past and present ? meaning saltwater or - brackish or clean fresh water ways

what are your operating water temps at ? at idle and mid range and WOT ? .

Engine serial number is 1A652875. The boat was bought used from a guy (he was the original owner), not used from a dealership, and always used in fresh water. Im going to try to get to the boat today to check the operating temps however, I do check the temps all the time and they are never what I would consider off. Thanks again for your help.

Finally was able to get the boat out today. All temperature gauges are operating normally according to the digital panel. Thanks for any help

just to let you know the engine was changed out under full warranty with very little engine hours and has a different engine serial number than original engine. I do know the current engine serial number thou.

Anyways so what temps is the engine running at since you mention normal ? different engines have different normal running temps.

IMO your O 2 sensor (s) possible are getting contaminated by something going thru the exhaust and or possible by water and or condensation.

He put yet another oxygen sensor on and the boat is no longer coding. I will let you know what happens when we put it back in the water in the spring.
Thanks for all of your help.

My apologies if referring to me. Bad O2 sensor was my issue.

I installed the Vesselview Mobile device on my 2003 Sea Ray 280 Sundancer which has a single 496MAG S/N 0M376155. After the install and starting the boat I immediately have 5 fault codes. How do I determine if they are an issue and even applicable to my engine? Engine idles around 670-700RPM (is that normal, or low?).

-Code 451-25 Pilot Pressure (The input circuit for the sensor is below the valid limit)
-Code 701-24 Level sensor tank A (The input circuit for the sensor is below the valid limit)
-Code 1031-24 Steering Position (The input circuit for the sensor is below the valid limit)
-Code 1012-25 Engine or drive trim position (The input circuit for the sensor is below the valid limit)
-Code 702-24 Level sensor tank B (The input circuit for the sensor is below the valid limit)

Thanks in advance! For all I know, these codes aren't applicable to my engine or don't mean anything...

depends if you have those or not and if you have DTS as well ??