Beeping 05 Avy

[knotguilty 6]

Hey guys, first of all being new to surfing and Centurions this site is fantastic. Kept me out of all kinds of trouble already and showed me how to make an awesome wave to learn on. (For another post)

 

So I just bought a '05 Avalanche C4 and the previous owner disconnected the warning buzzer. I connected it back up and now I know why. I'm getting the 2 beeps every minute warning and the scan tool is giving me the following faults:

 

40 MAT CKT LO

94 PITOT CKT LO

75 FUEL LVL CKT HI

119 STEER CKT LO

104 SEA TMP CKT HI

191 FUEL LVL 2 CKT H

 

None of these warnings are on the list of faults that should trip a warning but I assume that the beeping has to do with the MAT CKT LO fault because the manifold air temp is reading 32F. Are there any other checks I should do before I buy a new sensor? I assume I need a new Air Pressure and Temperature sensor? My engine S/N is OM398369. Is Part # 885165 the right part? I don't want to sound cheap but they go for ~$170 and would like to make sure I'm getting the right part.

 

That all being said the Lake/Sea Temp is also reading 32F. I looked all through the boat and I did not find a temperature sensor on the sea water side of the cooling system. There is a pressure sensor on the transmission cooler block but no other sensors. I assume that the SEA TMP CKT HI fault and the Lake/Sea Temp reading of 32F is because I don't have this sensor similar to the other faults on the list?

 

The boat runs great other than the beeping and I would like to hook the buzzer back up just in case there is there is a real problem I need to know about. Any help on this would be appreciated.

[knotguilty 6]

A few more things that may be worth mentioning. The scanner always shows that the shift position is in gear and the available power has been cut back to 89%. I have cleared both areas of faults and the faults above come back.

[CenturionSkier 43]

knotquilty,

 

40 MAT CKT LO Very important, this is your problem. Sound like you have a bad sensor.

 

These are not used by Centurion and will not cause a code. They are options used by I/O's or boats with the Mercury Video Dash.

94 PITOT CKT LO

75 FUEL LVL CKT HI

119 STEER CKT LO

104 SEA TMP CKT HI

191 FUEL LVL 2 CKT H

[truekaotik 458]

knotquilty,

 

40 MAT CKT LO Very important, this is your problem. Sound like you have a bad sensor.

 

These are not used by Centurion and will not cause a code. They are options used by I/O's or boats with the Mercury Video Dash.

94 PITOT CKT LO

75 FUEL LVL CKT HI

119 STEER CKT LO

104 SEA TMP CKT HI

191 FUEL LVL 2 CKT H

. I second C... Since my 2 beep code ive been Studying up on these fault codes for our year engine. The rest of the code list you will always have with a key on not running situation.. MAT Sensor issue would be my guess as well...but I'm new at the scanner thing for this boat... Just trying to help..

[truekaotik 458]

It will run better than great then.....after you replace sensor and restore 100% power also ;-)

[knotguilty 6]

Thanks CenturionSkier & truekaotik! I order sensor 885165 today. Should get it in the mail this week. I will let you know how this turns out after I install it next weekend.

[knotguilty 6]

I installed the new sensor and the beeping stopped for a short period of time. The sensor readings appeared to be correct then began to climb steadily (300F+) then the readings went back to 32F. Almost looks like the sensor got too much juice and burnt up. When I pulled out the sensor I didn't see any signs of any problems. When I reinstall the sensor it now acts just like the old bad sensor. Looks like I just burnt up a $170 sensor and the beeping is back

 

At this point I'm thinking I need to put a multi-gauge across the connector. Does anyone know what voltage the MAT sensor runs on? Any thoughts on where I should look for the source of the problem?

[truekaotik 458]

What does your scan say now?? Very odd...

[knotguilty 6]

Same as it did before. 40 MAT CKT LO came back after the gauge went high and went back to 32F. The beeping stopped and the 40 Mat CKT Lo went away for a good 30 minutes. I still have not had a chance to start the boat. I have been doing general maintenance i.e. changing the impeller, serpentine belt etc. today getting ready for a run with some buddies on Sunday.

 

One thought... I did have a battery charger on the battery with the ignition key on. Voltage reading on the scan tool was 13.2 is it possible this burnt up the gauge. I wouldn't think so but worth mentioning.

[knotguilty 6]

Did some searching online. The MAT sensor should run on 5V and go from ~25K ohms at 0F to ~185 ohms at 210F. Where the sensor was reading 300F+ I would say the sensor had a internal short from the factory or the voltage to the sensor was too high. I will check the voltage at the connector today to see if it is running at 5V. While I'm at it, I will also check the resistance across the sensor with a multimeter.

[knotguilty 6]

The sensor supply voltage is 5V and the resistance across the sensor is 8100 Ohms. Also when I blow on the sensor (make it warmer) the resistance drops. All good things.

 

Now I know that the sensor has a connection (both source and ground), the source voltage is correct and the sensor is trending correctly. So what is the correct Ohm reading for ~65F. I found this page but the charts in there are too coarse to tell where I am on the graph. If I was to guess the sensor is reading just about right.

 

Maybe the sensor in the boat wasn't right to begin with? My engine S/N is OM398369. Its a 2005 350 Murcruiser. Both the new and the old sensor are Bosch part #s 0261 230 075 / 12568929. This cross references to Quicksilver part # 885165. Is this the right part for my boat?

 

The other option...Gulp....My ECM is bad. Are there any self checks on that side?

Edited November 6, 2011 by knotguilty

[truekaotik 458]

I wa afraid to say the ECM next :-( if your wire isn't frayed anywhere and grounding out or corroded I would assume the ECM has a glitch or internal short... Sorry bro I'm no more help...

[CenturionSkier 43]

MerCruiser does not have model years. They work by the engine serial number. Take your serial number to any local Merc dealer and they can look up the part number for you.

 

Good luck!

[truekaotik 458]

Do check your wires, I would hate for you to replace the ECM to find out it was a simple wire issue... The connection or corrosion could be affecting the vast spikes in your explanation, especially since the sensor didn't fry instantly... I'm just trying to help, I am not a marine tech...Hopefully one will chime in if we keep you ontop of the discussion ;-)

[knotguilty 6]

http://whipplesuperc...asp?ProdID=1270

 

Anyone know what they mean by "Common issues such as the IAC failures". Isn't a IAC the same as a MAT sensor? If this is a common problem I would think there would be more information on this but I can't seem to find it. If any one knows how to conclusively determine there is a ECM problem I could use the help.

[CenturionSkier 43]

I believe that the IAC stands for Idle Air Control and MAT is Manifold Air Temp, but not sure. If that is correct then they are not the same thing.

[knotguilty 6]

Talk about things to be Thankful for. I brought my Avy to the dealership to look a the MAT Sensor error. Ended up just being a loose connection at the main connection to the ECM. Where it was a simple fix they didn't even charge me. Now to get the boat back on the water!

[truekaotik 458]

Sweet deal bro :-) very good thanksgiving for you!!! Glad everything worked out!