Exhaust Temp Sensor troubles

Note: This site contains eBay affiliate links for which SeaDooForum.com may be compensated


New Member
2016 Spark 3-up 900 HO ACE, ~60 hours on it

Got a check engine warning last weekend, which BUDS said to be Exhaust Temp Sensor related*. Spark did not go into limp mode. Continued to run just fine, aside from the loud-ass occasional beeping. Pulled upper deck off and replaced sensor with OEM from dealer. In talking with mechanics there, one suggested that wires going to sensor (AT sensor) sometimes failed and another mentioned a spot near front of engine where wires could rub on exposed head gasket.

*I recall code as P0281 or P02081, but that doesn't match what I can find online. Regardless of #, the description definitely said Exhaust Temperature Sensor circuit

Prior to replacing sensor, I checked continuity of both wires between sensor plug sockets and maybe 2" up the wire. This seemed to be where mech was describing possible failure point and where wires were bent at sharpest curve. Anyway, both showed continuity that didn't change with me wiggling the wires, so I went ahead with sensor replacement.

Buttoned it all back up and dunked Spark in water today. Check Engine warning was there immediately, so I drove to same, nearby dealer. They read codes and it still said trouble with Ex Temp Sensor, but there was also another new code "P0546 Exhaust gas temperature sensor open circuit or shorted to battery". Mechanic gave me deer-in-the-headlights look and left conversation. So...I need some guidance and hopefully some firsthand experience from someone who has tackled similar issue. Here's my plan of attack. I'll take any advice you may have.

1--check larger section of wire for continuity. 2" seemed like enough to hit the problem spot, if it was there, but I have 18" to work with

2--chop into wiring harness and bypass this last 18" of wire, rig my own connections to new sensor. If problem goes away, I can then work on making these connections waterproof and replace plug end with proper (Bosch?) plug.

This is where I run out of steam. Beyond these exposed 2 wires that go to rearmost sensor, the rest of the wire is inside the wiring harness. While not impossible, it seems really, really, really unlikely to have a problem inside a bundled, protected wiring loom. I could see checking the continuity of the two wires all the way to the fuse box or ECU, but I don't know that they actually terminate there. If so, where can I find a wiring diagram?

My dealer, who I don't fully trust anyway, is booked out until September right now. Next closest dealer is 150 miles away. I'm a mechanical guy with prime weather wasting away. Hoping that someone here has some ideas that will help lead me back to the water.

Let me know what you've got. Thanks. Jef in Central Washington
Having the same issue, and i don't have the correct tools to disassemble connector .
Yeah dealer is not sure what to do they have never heard of this before . Might be the wires are breaking at the zip tie location on the sensor or where they zip tied them to the exhaust hose .

Did you have any luck ? I Did purchase a 2014 service manual when I originally bought a couple of machines so i have the wiring diagram, and also have a BUDS system to look at codes and things .

for this you need to measure the ohm reading 2280-2736 at temperature between 19-21 C9 66-70 f) on pin numbers A-H4 and A-J4 on the wiring harness .

But without special tools to take apart connector they don't want you probing the connector itself a damage may occur and then have intermittent contact permanently.

My sensor new and used showed open
Last edited:
pdooley--Thanks for the reply.

Both my new and used exhaust temp sensors measured 1980 ohms at room temperature. My used sensor got boiled on stove and resistance dropped to 180ohms. This was fairly consistent with some info I found on Bosch website (though it was for a different, but similar looking sensor). I've recently had a temp sensor on Kawasaki ZRX go bad, though it tested fine in boiling water. I splurged the $40 for new Seadoo sensor, as it wasn't too expensive and I didn't want to ignore the obvious.

You are correct that the next likely place for wires to fail would be near where they are ziptied to exhaust hose. It was shortsighted of me to NOT test continuity farther up the wire when I had all that $hit apart the first time. That's why I have #1 in my diagnostic plan, above.

As for connector plug going bad, it wouldn't be the FIRST time that's happened to a connector on this particular Spark. I won't bore you with that story, but won't hesitate to chop that plug off and wire up my own connections to new sensor (#2 in my plan). Doing this would mean it's not waterproof, temporarily. If it solved the problem, new plugs are $17 through dealer, though I'd bet it's a standard Bosch plug available many places for less.

Any chance you could send me a pic/link/copy of that wiring diagram you mentioned?
Did you have any luck ? Trying to decide to cut into the wiring harness and splice in one from different ski that got destroyed , or not real sure from here .

I really want Sea doo to take care of this problem , but i don't have a month to wait on service dept !

Just wish I knew it wasn't somewhere farther up in the harness and I don't really want to start cutting back insulation on the wires to be checking for continuity and creating other electrical issues from corrosion farther down the line .
Time. Just so little time...

I think my next move is to chop wires back near entrance to wiring loom on/near head, leaving plenty to work with in the future, of course. I will then run new wires from this cut to sensor and connect using whatever cobbled $hit I can find in my garage. Waterproof--NO. But if the problem persists, then I know it is either wiring harness or ECM, right? Or it works and I get out of Spark-jail.
Thats what i'm going to do now . Did this put your machine into limp mode or just check engine status ? my machine just has the engine light on but not in limp mode , thinking about leaving it alone and running it till winter (less than a month ) then letting dealer find a resonable fix for it .
But like most dealerships the guys working on these thing just bought their first socket set last week when they were hired on !!
so Shit I just talked myself into it

going to cut it back toward the head and splice another in
Wish me luck
Ok. I found it (I'm pretty sure) Fingers crossed

I cut the wires about 4" from where they enter the main harness OR about 4" ahead of where they are ziptied to the exhaust tube. Mine had 2 zipties there, before wires went off to the actual sensor.

I was testing continuity through the plug to the two fresh ends I now had. White wire = good. Black wire = no connection. I moved up the wire from the plug and sure as shit, RIGHT where the zipties were the continuity stopped. I pulled back the insulation and visibly broken.

I am going to solder wires back on, heat shrink the connections and hopefully get this biatch back in the water.

Wanted to pass this on ASAP, as we are spending our Sundays much in the same way. Hope this info helps.
Haven't found the break yet , all the way to the engine block and all is good so far

But good for you !!
pdooley--I wasn't holding out on you, but forgot to mention this tidbit from the better mechanic at dealer. He said that most exhaust sensor wires fail close to the sensor plug or in the plug, but that he HAS seen a couple failures at front left corner of block/head, too. Crapload of wires in there and it makes little sense to me that the exhaust sensor wires would be exposed at this point, but the head gasket sticks out and it's sharp. Apparently some builds have wires close enough to get cut and short. That could be you.

I don't have a picture of this, but area he pointed out is (facing driver's front) the front left corner of head, right at the headgasket area. Behind/near the oil filter. On the Spark he had at the shop, the wires seemed really close and just hanging there. When I looked at mine, there was a loop around the wiring harness to purposely hold it away from head gasket and I had a mile of room to spare. This could be a place to check next.

I hope you don't have to go THIS far, but my Spark in question had an odd failure within the first hour on the water. It was an IBR problem that prevented forward propulsion. Spark would run and beep, but no-go. Turns out it was a shitty connection of the IBR circuit fuse in the fuse box. The (only) way they found (stumbled upon) the problem was when they pulled the fuse to check it, they noticed it was barely held in there. The "socket" that the prongs fit into were mis-shapen, loose and wouldn't hold a solid connection. Very random, but apparently, this sort of thing happens with Sparks.

Don't have a confirmation that my problem is solved. Went paddleboarding instead. Will keep at it tomorrow and report back.

Good luck!
Well I ended up cutting the wires back about 6 inches , measured resistance from there back to the sensor and it showed the 2500ohms.so i thought that was good . But what to do now / so I cut back the wires as far as i could go back to the larger loom at the head and spliced in some wire , and no more codes ,everything was fine . But I never did find the problem ,which is worry some but it is working and back in the rental fleet so only time will tell

good luck to you
I am also having issues with 2017 Seadoo 300 rxtx exhaust sensor and female plug that goes onto the sensor. I can seem to find the correct female plug with pigtails. Someone mentioned that Seadoo dealer had this part, but when i went there they did not show a part number. I think you mention bosch might have one too. Does anyone know a part number for bosch or a link etc and so I can get this female cap with pigtails?