Volvo Penta 350 Throwing 698 & 699

[SouthCarolina1]

Got a 2008 Volvo Penta 350 running great but occasionally throwing

1. SPN: 698 Engine Coolant Temp Gauge (PWM2)(DTC 1633) FMI: 5 Current Below Normal or Open Circuit
2. SPN: 699 Drive Oil Gauge (PWM3)(DTC 1635) FMI: 5 Current Below Normal or Open Circuit

I've read a few forums saying it might be a bad knock sensor throwing off the other sensors. Should I start there and where is it? Complete engine diagnostic file showing serial numbers have been attached.

 

[muc]

do you have can bus gauges or analog?
post a pic of the back of the gauges

 

[SouthCarolina1]

I don't but I can. What will that tell you?

 

[muc]

Those codes can go two different directions. So need to know what gauges are installed to know which direction.

 

[SouthCarolina1]

It has a digital screen display instead of the round individual gauges if that tells you anything. Ill be back in a few days.

 

[SouthCarolina1]

Those codes can go two different directions. So need to know what gauges are installed to know which direction.

It has a screen like this

 

[muc]

That is considered can bus.
The codes you posted are saying there is something wrong with the analog gauges === that you don't have.
These codes usually come up as 3 codes. temp, oil pressure and trim.
Why the Diacom report is only listing 2 and one of those shows as drive oil gauge. I don't know, but I see the report lists a 2008 engine when it's a 2016-2017 engine might be part of the reason.
And why some engines with can bus gauges throw these codes and others don't, I don't have an answer for that either.
Either way, you can disregard these codes.
But if you haven't corrected all the over temp codes, that would be a priority.