Post cat oxygen sensor code

[CraigXLV]

I have a 2008 XLV with the Indmar Assault 340. CHeck engine light has been on and I took it to a local dealer (non-Moomba/Supra) to read the code. I was told it was throwing an active code for the post catalytic oxygen sensor on both sides. I have read that on some years this was a known issue and a software update can resolve this. I have also seen some fixed by cutting the wire and placing a resistor between the two wires to the sensor to fool the computer. I found new ones on Amazon for around $55 but was wondering if anyone else has experienced this and how they fixed it. The guy that read the codes reset them, but the light came back on within 15 minutes this weekend on the lake.


Craig

2008 XLV Gravity Games

[BrokeGuy]

I'm a automotive technician, IMO software updates are to fix issues, that happen within the first few years, due to software issues from the factory. That being said you have a you've been 9 to 10 years with no light. You have a issue that has failed, wether it be a oxygen sensor, wiring, or pcm. If it's a catalyst efficiency issue, the cats are bad but something killed them.

Sent from my SM-G935V using Tapatalk

[Engine Nut]

I have a 2008 XLV with the Indmar Assault 340. CHeck engine light has been on and I took it to a local dealer (non-Moomba/Supra) to read the code. I was told it was throwing an active code for the post catalytic oxygen sensor on both sides. I have read that on some years this was a known issue and a software update can resolve this. I have also seen some fixed by cutting the wire and placing a resistor between the two wires to the sensor to fool the computer. I found new ones on Amazon for around $55 but was wondering if anyone else has experienced this and how they fixed it. The guy that read the codes reset them, but the light came back on within 15 minutes this weekend on the lake.
Craig

2008 XLV Gravity Games

The sensors behind the catalytic converters on a 2008 model are post catalyst temperature sensors. not oxygen sensors. The post cat sensors proved to be problematic and since they were not required by law or needed to control engine operation, we essentially disabled them. There are two ways to disable them. One is to have the ECM/Computer recalibrated. The other way is to cut the wires between the sensor and the plug and install a 470 ohm 1/2 watt resistor across the wires. This tricks the ECM into thinking that the sensor is functioning and the issue goes away.

[CraigXLV]

BrokeGuy, the boat is new to me so I don't know when it came on. Thanks engine nut. Where would one find such a resistor?


Craig

2008 XLV Gravity Games

[JHutch]

You can get them at Radio Shack if you still have one by you. That's where I got mine. I have the exact same boat and had this issue last summer, putting the resistors in fixed my issue.

[moombahighrider]

BrokeGuy, the boat is new to me so I don't know when it came on. Thanks engine nut. Where would one find such a resistor?


Craig

2008 XLV Gravity Games

Amazon:

E-Projects 100EP512470R 470 Ohm Resistors, 1/2 W, 5% (Pack of 100) https://www.amazon.com/dp/B0185FIDF0/ref=cm_sw_r_sms_c_api_jP74yb570FTKK

[moombahighrider]

They have a pack of 10 as well

[CraigXLV]

JHutch, did you simply solder the resistor between the two wires in the cable and then heat shrink seal the finished product? Similar to this video?

https://youtu.be/Ioo0sEUUjLM


Craig

2008 XLV Gravity Games

[New Guy]

My '14 mojo with the 345 does something similar. If we are running really heavy ballast the fault will go out but if we are just cruising around the lake the fault returns. It's more annoying than anything. Maybe Engine Nut can chime in. I believe the fault is 3051

[JHutch]

That's exactly how I did mine. The CEL put my boat in limp mode and I wanted it fixed ASAP since it was 4th of July weekend. It has been fine ever since.

[trayson]

I have a 2008 XLV with the Indmar Assault 340. Craig

2008 XLV Gravity Games

If you have the 340, it's the Indmar 340 CAT ETX, not the Assault which is the 325.

[CraigXLV]

Sorry Trayson. I didn't realize the Assault was only the 325 and the 340 had all that acronym soup going for it. I'm a newbie and really appreciate the knowledge here in this group.


Craig

2008 XLV Gravity Games

[trayson]

Sorry Trayson. I didn't realize the Assault was only the 325 and the 340 had all that acronym soup going for it. I'm a newbie and really appreciate the knowledge here in this group.


Craig

2008 XLV Gravity Games

No problem! I went months thinking that I actually had the 325 engine only to find out from this forum that I really had the 340! I was pretty stoked to find out.
I figured I'd help clarify because it might confuse some people and they might think you have the other engine. But yeah, our 340's have CAT's. :-)

That said, I found it interesting that on the leads that go to my sensors on the top of my manifold, I have butt connectors, so either they used butt connectors at the factory to connect the sensor to the harness, or my sensors were replaced somewhere along the way.

My boat isn't throwing CEL's so I didn't sweat it.

[CraigXLV]

Funny, I actually thought I had the 325 until I joined this group and saw that post. I too was excited about having the 340 as well.


Craig

2008 XLV Gravity Games

[trayson]

Funny, I actually thought I had the 325 until I joined this group and saw that post. I too was excited about having the 340 as well.


Craig

2008 XLV Gravity Games

Yeah, that's rad. Looks like we have the same boat. I have done a lot to mine, so as you have questions I'll be happy to help with any insight I can offer.

[CraigXLV]

I got the resistors soldered in yesterday and after 3 cranks and a battery disconnect my CEL is now off. Thanks for the help everyone.


Craig

2008 XLV Gravity Games

[OHSupra]

So my 09 supra with the 340 Cat is intermittently throwing the service required code, I had it checked and it was a bank 2 O2 sensor. I figured I could just change out the sensors no issue. But they look to be about $70.00, so with the above information confusing me a bit... are the 4 sensors the same but just read different signals or are they different sensors all together.... and for good measure anyone able to confirm part numbers? Thanks

[Moombas]

My '14 mojo with the 345 does something similar. If we are running really heavy ballast the fault will go out but if we are just cruising around the lake the fault returns. It's more annoying than anything. Maybe Engine Nut can chime in. I believe the fault is 3051

Did you ever find a fix? I took my boat out for first time this season, only thing that has changed is my prop and now I got this code.
Old prop was a 1235- boat has 480hours on it no issues till now
New prop is a 2079 (I will be normally running extra 1000lbs lead now)

We surfed for hours yesterday no issue, go for cruise around the lake to end the day and got the light after a 10 min 20mph cruise. I guess I should replace 02 sensor? Go back to my old prop?
Or just a weird First day out problem?