2008 SAN 210 Check Engine light and reduced throttle issue

[Spud]

2008 SAN 210with Excalibur 343 throws red check engine light and reduces throttle after a few minutes running only at the start of a day on the water....

This is a strange one that I would like to put to bed finally with some help from the community hopefully...

So when we head the lake this happens every time without fail....

Turn Battery Isolator switch to the on position. (boat is always completely shut down after leaving the lake .
Launch Boat
Fires up first time every time
Head out through the no wake zone no issues
Out of the no wake zone throttle up to cruising / planning speed and cruises along beautifully for 3-4 minutes possibly longer with no issues... sometimes PerfectPass on sometimes off.
All of a sudden I get a check engine light and reduced revs (always both) no other messages on the gauges.
Pull throttle back to idle
Idle for 5-10 seconds
Hit throttle again back up to previous speed runs perfect.
Will and always does run perfectly all day with no more issues after this initial warning light and reduced revs

Can stop the boat turn off re start & run all day with never another issue.

Can leave in the lake all night with toggle switch moved to the down position so that the bilge pumps can work and hit the key pad to start the next day and still no issue.

As soon as we turn the battery isolator off to completely shut down the boat the issue returns but we simply run through the above again and the boat will run perfectly again.

Any thoughts from the community?

Steve

[swatguy]

I had a similar situation , pretty much identical issues. It ended up being my throttle position sensor. My red light would come on at various speeds or under load intermittently while cruising lot towing riders or surfing , sometimes at speeds just above idle. I thought maybe I was have tranny fluid issues , something was going wrong there. The red light was very intermittent . Boat was little sluggish , but boat would run and pull riders no misses or anything really out of the ordinary . I noticed I really had to hammer the throttle to get some response .


Dealer had it to chase down the problem. Replaced the throttle position sensor and all is well. Still not sure why it kicks the engine code when that’s failing , but that’s what fixed mine on my 08 at 812hrs. Currently 900 and issue hasn’t come back.

[jpwhit]

You need to read the engine codes from the ECM using Rhinda Diacom. If it is the throttle control position sensor (TCP) or the throttle position sensor (TPS) there will be codes stored in the ECM. If you have to replace the TCP, then the ECM will need to be reflashed because the original TCP is no longer made and the replacement requires changes to the ECM programming.

[Spud]

jpwhit What is the difference between a TCP and TPS?

[swatguy]

JP made a great observation. I actually think it was the TCP not the TPS. I made the mistake when talking with my dealer and now o made that same
mistake here. I planned on pulling my service record from my file at lake with part numbers and code. 99.9% sure this was part they used to replace. My apologies.

https://nautiqueparts.com/potentiome...-sensor-2007-/

[jpwhit]

TCP measures the position of the throttle handle. TPS measures the position of the throttle body butterfly. Both are mounted on the engine. The TCP is just bolted to the top of the engine and the throttle cable connects to it. The TPS is mounted on the throttle body. Both sensors are actually 2 sensors in the same housing. The ECU is always checking that both sensors agree with each other for safety purposes. If they don't agree, you get the kind of behavior you're seeing. And I've seen cases where they behave very strangely such as what you're seeing when they only act up after the main power has been off.

Using Diacom, you can actually watch the sensor voltages of all 4 outputs, 2 from each sensor, as you move the throttle handle and the ECU opens and closes the throttle body butterfly. It's usually pretty easy to see if something's not right. But there are also always codes stored in the ECU if it's seen a issue in the past.

[jpwhit]

You can also check them with a meter if you take them off the engine, but it's much tricker to figure out what is correct and incorrect because each sub-sensor in the assembly is a potentiometer with a different resistance value. They do that such that if wires get shorted together within or outside the sensor that one sub-sensor doesn't fool the ECU into thinking both sensors are good. So the ratio between the two potentiometers should be the same, but the resistance values will be different.

[Spud]

Does any one have a link to where I can find/purchase a TPS?