Warning buzzer 496HO
 

I was out yesterday and I started hearing the buzzer on my '04 496HO. It had two short beeps every couple of minutes, not a continuos beep. The oil pressure, and temp looked fine according to the gauges and the gear oil bottle was OK. What else could this be? The engine seemed to be fine otherwise.

Where can I get a scan tool for this engine and how much?

Dave M.

Re: Warning buzzer 496HO
 

The 2 beeps per minute generally indicates you have an active fault of some sort. There are many faults that can cause this. A scan tool is the easiest way to deturmine what you have. I got mine at Rinda (Link below). I got mine a couple years ago for about $500.

http://216.230.203.183/marine/marine.htm

Re: Warning buzzer 496HO
 

Just my opinion, but I would stay away from a handheld scan tool.

I would consider instead two options:

1) Buy the Diacom software ($80.00 more than a handheld but well worth it - assuming you have a laptop)

2) Buy and install a SC1000 series smartcraft display that will display engine fault information. If you buy one on ebay and install it yourself, you could do it for less than half the cost of a handheld scan tool.

Dave

Re: Warning buzzer 496HO
 

that happened to a buddy of mine on his 496 Mag. He bought the Smartcraft monitor and everyhting looked good. After going round and round with the Merc techs, he finally got someone to agree to replace the wiring harness. It took a few monthe to get them to do it, but once he did, he hasn't had another problem with it.

Re: Warning buzzer 496HO
 

Thanks Guys!

Does the Diacom software come with all the necessary connectors to connect the engine to a laptop?

I was already thinking of buying a Smartcraft monitor.

Dave M.

Re: Warning buzzer 496HO
 

Yes Diacom comes with adapters and cable for MEFI 1-4 and PCM/ECM555.

Dave

Re: Warning buzzer 496HO
 

Installing a Smartcraft display is easy, but if you want more info order the "Smartcraft Applications and Display Products Technical Guide" from Merc. Part # 90-891965. List price $21.45.

Dave

Re: Warning buzzer 496HO
 

have been looking at the diacom soft ware how do you like it, how does it compare to the merc spx cds package????? any help I would be greatful

Re: Warning buzzer 496HO
 

Joe,
I have not used or even seen the CDS. I really like Diacom, but think it could be better. Do you have any screen shots of CDS that you could post?

Dave

Re: Warning buzzer 496HO
 

I just called Rinda and the Diacom sounds like a better deal over the scan tool. The scan tool is $400 and Diacom is $579 but sounds like it has a lot more capabilities.

Re: Warning buzzer 496HO
 

darn, I really wish someone would ask for a burned copy or two, I know I would be willing to offer something for one

not suggesting anyone burn a copy, but wow, could someone make a couple bucks and help some fella's out

:D :drink:

Re: Warning buzzer 496HO
 

When I saw the price of the software that came to mind. They told me that there is some type of hardware lock built into the pc cable. If you don't have the cable the software won't work. Might be BS??

Re: Warning buzzer 496HO
 

dave luv it just from the screen shot the spx cds only allows 4 graphs at a time going to order this week!!!! as for verses hand held 1) does not compair like apples to oranges 2) you need to add in price of lap top

Re: Warning buzzer 496HO
 

I ordered the Diacom SW yesterday. I'll let you guys know how I like it when it arrives.

Back to my problem.... I checked to make sure all electrical connections were tight. I ran the boat for about 2 hours on Tues. and no buzzer. I'll see what the code was when the SW arrives. I did notice that my temp was reading slightly lower than normal. Maybe cause the water and air have cooled? This is my first season with this engine so I don't have a lot of history. My previous engines always ran around the same temp regardless of air and water temp.

Re: Warning buzzer 496HO
 

My Diacom SW arrived. I'm pretty happy with it after my first testing session. The only bad thing is it does not come with built in Mercruiser documentation. Does anybody have the docs in .pdf format? Below are the active codes that were shown. Does anybody know what they mean?

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

Re: Warning buzzer 496HO
 

Dave,
None of these faults mean anything, they are due to missing optional sensor. Did you retrieve the fault history? That is where the cause of the alarm will be recorded. Post it if possible.

Dave

Re: Warning buzzer 496HO
 

part 1
DIACOM ® Diagnostic Status Report

10/09/2005 14:41:48


1. VEHICLE CONFIGURATION

Engine Make: N/A
Engine Serial No: N/A
Model Year: N/A
System Type: MerCruiser PCM555

2. PERFORMANCE DATA

Parameter Description Value Unit

Available Power 100 %
Baro Pressure 14.54
Battery Voltage 14.57
Coolant Temperature 163.40
Engine Speed 753 RPM
Fuel Flow Rate 1.54 GPH
Fuel Level 1022 #
IAC Duty Cycle 11.30
Lake/Sea Temp 431.60 °F
Manifold Absolute Pressure 8.67
Manifold Air Temperature 75.20
Oil Pressure 51.38
Paddle Wheel 0 Hz
Pitot ADC 0 #
Port Exhst Cool Temp 118.40
Sea Pump Pressure 2.24
Sensor Power 5.00 VDC
Spark Advance -5.38
Starb Exhst Cool Temp 98.60
Throttle Position 2.15
Throttle Sensor Voltage 0.67
Trim Position 0 #
Trim Volts 0.00 VDC

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

Freeze Frame Data:

0 FUELPUMP RLY CK
--------------------------------------------------------------------
FF Baro Pressure 14.85 PSI
FF Battery Volts 7.47 VDC
FF Sea Pump Pressure 0.72 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 125.60 °F
FF Coolant Temp 161.60 °F
FF Demand 0.12 %
FF Engine Speed 0 RPM
FF Engine State Stall
FF FPC Total 0.0 Counts
FF Frequency Count 1
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 0.00 %
FF Main Pwr Relay Requests 32772.0
FF Manifold Air Pressure 14.79 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.17 %
FF Available Power 100 %
FF Run Time 63.12 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.12 %
FF Trim Position 0.00 %

Re: Warning buzzer 496HO
 

1 TRIM CKT LO
--------------------------------------------------------------------
FF Baro Pressure 14.54 PSI
FF Battery Volts 8.93 VDC
FF Sea Pump Pressure 0.21 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 60.80 °F
FF Coolant Temp 62.60 °F
FF Demand 0.12 %
FF Engine Speed 0 RPM
FF Engine State Stall
FF FPC Total 0.0 Counts
FF Frequency Count 521
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 0.00 %
FF Main Pwr Relay Requests 32772.0
FF Manifold Air Pressure 14.05 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.08 %
FF Available Power 50 %
FF Run Time 65.20 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.12 %
FF Trim Position 0.00 %

2 STEER CKT HI
--------------------------------------------------------------------
FF Baro Pressure 14.54 PSI
FF Battery Volts 9.17 VDC
FF Sea Pump Pressure 0.30 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 62.60 °F
FF Coolant Temp 62.60 °F
FF Demand 0.12 %
FF Engine Speed 138 RPM
FF Engine State Crank
FF FPC Total 0.0 Counts
FF Frequency Count 516
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 429.80 °F
FF Engine Load 0.00 %
FF Main Pwr Relay Requests 33812.0
FF Manifold Air Pressure 14.22 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.19 %
FF Available Power 50 %
FF Run Time 65.20 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.12 %
FF Trim Position 0.00 %

Re: Warning buzzer 496HO
 

3 FUEL LVL2 CKT H
--------------------------------------------------------------------
FF Baro Pressure 14.54 PSI
FF Battery Volts 9.17 VDC
FF Sea Pump Pressure 0.29 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 62.60 °F
FF Coolant Temp 62.60 °F
FF Demand 0.12 %
FF Engine Speed 138 RPM
FF Engine State Crank
FF FPC Total 0.0 Counts
FF Frequency Count 517
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 429.80 °F
FF Engine Load 0.00 %
FF Main Pwr Relay Requests 33812.0
FF Manifold Air Pressure 14.22 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.18 %
FF Available Power 50 %
FF Run Time 65.20 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.12 %
FF Trim Position 0.00 %

4 PITOT CKT LO
--------------------------------------------------------------------
FF Baro Pressure 14.54 PSI
FF Battery Volts 14.00 VDC
FF Sea Pump Pressure 0.96 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 62.60 °F
FF Coolant Temp 62.60 °F
FF Demand 0.00 %
FF Engine Speed 1220 RPM
FF Engine State Running
FF FPC Total 40.1 Counts
FF Frequency Count 477
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 10.96 %
FF Main Pwr Relay Requests 33812.0
FF Manifold Air Pressure 8.43 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.45 %
FF Available Power 0 %
FF Run Time 65.20 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.00 %
FF Trim Position 0.00 %

5 FUEL LVL CKT HI
--------------------------------------------------------------------
FF Baro Pressure 14.54 PSI
FF Battery Volts 13.03 VDC
FF Sea Pump Pressure 0.87 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 62.60 °F
FF Coolant Temp 62.60 °F
FF Demand 0.00 %
FF Engine Speed 1133 RPM
FF Engine State Running
FF FPC Total 44.7 Counts
FF Frequency Count 485
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 12.71 %
FF Main Pwr Relay Requests 33812.0
FF Manifold Air Pressure 9.12 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.43 %
FF Available Power 0 %
FF Run Time 65.20 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.00 %
FF Trim Position 0.00 %

Re: Warning buzzer 496HO
 

6 CRANK SNSR
--------------------------------------------------------------------
FF Baro Pressure 14.70 PSI
FF Battery Volts 12.03 VDC
FF Sea Pump Pressure 0.64 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 134.60 °F
FF Coolant Temp 170.60 °F
FF Demand 0.00 %
FF Engine Speed 285 RPM
FF Engine State Running
FF FPC Total 25.2 Counts
FF Frequency Count 24
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 21.04 %
FF Main Pwr Relay Requests 33812.0
FF Manifold Air Pressure 14.31 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.02 %
FF Available Power 78 %
FF Run Time 57.77 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.00 %
FF Trim Position 0.00 %

7 CAM SNSR
--------------------------------------------------------------------
FF Baro Pressure 14.70 PSI
FF Battery Volts 12.03 VDC
FF Sea Pump Pressure 0.64 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 134.60 °F
FF Coolant Temp 170.60 °F
FF Demand 0.00 %
FF Engine Speed 285 RPM
FF Engine State Running
FF FPC Total 25.2 Counts
FF Frequency Count 25
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 21.04 %
FF Main Pwr Relay Requests 33812.0
FF Manifold Air Pressure 14.31 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.02 %
FF Available Power 78 %
FF Run Time 57.77 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.00 %
FF Trim Position 0.00 %

8 TPS1 NO ADAPT
--------------------------------------------------------------------
FF Baro Pressure 14.73 PSI
FF Battery Volts 9.52 VDC
FF Sea Pump Pressure 0.21 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 53.60 °F
FF Coolant Temp 51.80 °F
FF Demand 24.81 %
FF Engine Speed 439 RPM
FF Engine State Running
FF FPC Total 75.8 Counts
FF Frequency Count 1
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 25.17 %
FF Main Pwr Relay Requests 33812.0
FF Manifold Air Pressure 14.29 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.08 %
FF Available Power 50 %
FF Run Time 0.20 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 24.81 %
FF Trim Position 0.00 %

9 MAP INPUT HI
--------------------------------------------------------------------
FF Baro Pressure 14.85 PSI
FF Battery Volts 12.00 VDC
FF Sea Pump Pressure 0.03 PSI
FF Boat Speed 0.00
FF Manifold Air Temp 107.60 °F
FF Coolant Temp 141.80 °F
FF Demand 0.25 %
FF Engine Speed 0 RPM
FF Engine State Stall
FF FPC Total 0.0 Counts
FF Frequency Count 46
FF Fuel Level 0.00 %
FF Gear Position In Gear
FF Lake Temp 431.60 °F
FF Engine Load 0.00 %
FF Main Pwr Relay Requests 32772.0
FF Manifold Air Pressure 14.84 PSI
FF Oil Level 0.00 %
FF Port Tab Pos 0.06 %
FF Available Power 100 %
FF Run Time 63.83 hrs
FF Starboard Tab Pos 0.00 %
FF TPS Percent 0.25 %
FF Trim Position 0.00 %

Fault Log Data
Fault Descriptions Seconds

Battery Range High: 0
Battery Range Low: 0
Block Pressure is Low: 0
Compressor Temp Overheat: 0
ETC Motor Open: 0
ETC Motor Short: 0
Fuel Pressure Sensor Input High: 0
Fuel Pressure Sensor Input Low: 0
Guardian Strategy: 0
Knock Sensor 1: 0
Knock Sensor 2: 0
Low Oil Pressure Strategy: 0
Low Oil Remote Strategy: 0
Low Oil Reserve Strategy: 0
MAP Sensor 1 Input High: 25
MAP Sensor 1 Input Low: 0
MAP Sensor 1 Idle Rational: 0
Oil Pump Output: 0
Overspeed: 0
Port Clnt Overheat: 0
Starboard Clnt Overheat: 0
Warning Horn Output: 0
Water In Fuel: 0

Engine Run Time History:

Total engine run time: 65.33 Hours
0 - 749 RPM: 17.90 Hours
750 - 1499 RPM: 7.95 Hours
1500 - 2999 RPM: 5.28 Hours
3000 - 3499 RPM: 15.95 Hours
3500 - 3999 RPM: 15.38 Hours
4000 - 4499 RPM: 2.08 Hours
4500 - 4999 RPM: 0.75 Hours
5000 - 5499 RPM: 0.03 Hours
Over 5499 RPM: 0.00 Hours

Re: Warning buzzer 496HO
 

MAP Sensor 1 Input High: 25


Is this a problem? It looks like everything else reads 0 seconds?

Re: Warning buzzer 496HO
 

MAP Input Hi with a frequency count of 46 and last occurance about 1.4 engine hours ago. I think that (MAP sensor) is your issue right there.

Service Manual says:
Loose connection, corrosion, open (Lo) or Short (Hi) in circuit. Inspect circuit, Repair or replace harness.

Faulty Sensor. Replace sensor.

Dave

Re: Warning buzzer 496HO
 

Thanks Dave! Do you know where the MAP sensor is?

Re: Warning buzzer 496HO
 

It is under the cover towards the back of the intake manifold.

Dave

Re: Warning buzzer 496HO
 

I had the same exact problem. I still have not figured out what was the problem, I thought it was bad gas. So I added 91 in it and took it back out. It ran fine no beeps? I still want to have it scanned to see why it did that but I know its a faulty sensor.

Re: Warning buzzer 496HO
 

Thats a hellof alot of info there :eek: :D


Rob :D

Re: Warning buzzer 496HO
 

Hey Dave,

I made sure the map sensor was plugged in securely and I have not had a problem in over 4 hours of run time. I got the manual you suggested and it says that pressure reading should be between 8.41-8.99 at idle. I'm seeing slightly higher (9's) according to Diacom. As soon as I come slightly off idle it drops down into the 8's. I'm going to assume that everything is OK right now.

One more question. There is a "transom harness" that T's off to two connectors that are not plugged into anything. I guess that is what is giving me the "Trim Ckt Lo" and the "Steer Ckt Hi" codes. Can I just unplug and remove that harness so I don't have those connections bundled up in my engine compartment? Is there a way to put those connectors in "loop back" or something so those codes don't appear?

Why does Diacom say Lake/Sea temp 431*?


Thanks,
Dave M.

Re: Warning buzzer 496HO
 

Dave,

Good to hear you have made progress. Your MAP readings are consistant with the 496HO's that I have seen. They all seem to be around 9 to 9.5 PSI at idle (sea level).

You could disconnect the transom harness, but your may be using the mechanical throttle and shift trim limit connections (purple and blue wires with bullet connectors that connect to the trim pump). Check page 3A-32 in the diagnostic manual.

I have talked to an engineer at Merc and he said that there is no way to prevent fault codes (such as Trim Ckt Lo and Steer Ckt Hi) due to missing sensors. In the case of the Sea Temp reading, without a sensor connected the ECM does not trigger a fault code, it just shows a default value of 431 degrees.

Dave

Re: Warning buzzer 496HO
 

Thanks Dave! I don't have a trim limit, or "trailer" button. I have mechanical indicators so I cut the trim sender and limit wires out.

I'll try disconnecting that harness and see if anything happens. I just don't want it dangling back there if I don't need it.

Gotta love this technology. It takes the guess work out of things. I highly recommend the Diacom SW.

Dave M.