7 DTC error codes Are they related?

[gtxltd]

Hi Folks,
I'm hoping someone can tell me how to go about troubleshooting this or give me any insight on how to proceed. The boat is a SAN G25. The engine is PCM XS550 supercharged. The engine starts and idles. When you move the throttle forward nothing happens until it is very high then the engine revs but I quickly pull the handle back to idle.
These are the error codes:
DTC 2123 fpp1 voltage low
DTC 122 TPS1 voltage low
DTC 222 TPS2 voltage low
DTC 2121 FPP1-2 lower than expected
DTC 174 adaptive learn gasoline bank 2 high
DTC 111 IAT higher than expected stage 1
DTC 2135 TPS1/2 simultaneous voltages out of range
I feel like these may be related in some way. I'm hoping someone can point me to some wires or pins where I can check some voltages. I have already confirmed all the fuses have good voltage. Any help would be greatly appreciated,
Thanks,
Joe

[Scooter G]

Has the Throttle Base ever been replaced in your boat? If not, you bought a lot of time with the original.
Just my 2 cents.
https://www.planetnautique.com/vb5/f...s-210-230-2015

[Scooter G]

gtxltd, you may find this pdf helpful in chasing codes. It may not reference your particular ship, but the codes stay pretty consistent across PCM models.

PCM ECM Training Diagnostic Supplment.pdf

[gtxltd]

Hi Scooter. Thank you very much for your responses. Yes the throttle base was replaced May 2024. I was thinking that the throttle response problem was some kind of limp mode related to trouble codes, But do you think it's possible the throttle base could be bad again already?. I think the document you sent will help me a lot. Thanks again, Joe

[jpwhit]

That’s a bunch of codes. With that many codes, I would start with connecting DIACOM to the boat and watching a lot of those various inputs to the ECU live. Almost seems like a one of the ECU voltage references is possibly off. I think it’ll be a lot easier to get an idea of what’s going on seeing all the voltages in the live views.

The most common problems with the Throttle Base Assembly are related to the gear lockout and neutral signals. Not saying this can’t be caused by the TBA, but it’s not the typical common failure case. And some of those codes such as DTC 111 and 174 have noting to do with the TBA, but they do involve conversion of analog voltages to digital which depends on the ECU’s internal reference voltages being correct. The TPS codes can be caused by the rotary encoder in the TBA, which can certainly fail, but that’s not the portion of the TBA that has been causing all the typical early life failures.

What are date, time, and occurrence counts on all those codes. I can’t remember for sure if the LINC screen diag pages shows all that detail, of if you can only see that level of detail in DIACOM. If some of those codes haven’t occurred in a long time, or often, the situation could be much clearer.

[gtxltd]

Thank you jpwhit for mentioning DIACOM software. I will look into it. The document that Scooter G linked shows the 5V reference voltages in the pinout of both the MAP/IAT and TBA. I suppose it is possible that one bad sensor could bring down those 5V reference voltages. I plan to unplug the MAP/IAT and then TBA sensors one at a time to see if it gets better. I plan to try to clear codes by disconnecting power (I hope that works). If I can't get the answer I will look into buying the DIACOM software which seems to a no brainer if we intend to keep the boat. Thanks again to both jpwhit and Scooter G.

[Scooter G]

I saw this the other day, FYI:
https://www.planetnautique.com/vb5/f...iacom-software

[jpwhit]

The codes are stored in non-volatile storage in the ECU. Disconnecting power will not clear any codes. Some codes will auto-clear if they haven't occurred since a certain number of start cycles. The LINC diag screen doesn't have an option to clear codes? Even if you click on the code for more detail? It may be that capability is in the MasterCraft Diag screen, it's hard to remember that level of details sometimes.

[gtxltd]

jpwhit I believe you are right that I can clear the codes in the LINC diag screen. I am away from the boat and reading a bunch of mis-information on the web. Thank you.
Scooter G thank you for the possible rental opportunity information.