2008 rxt-x electrical problem

[Seadoojim1]

Having a no start issue with my 2008 rxt-x 255. I put the key on the post and have nothing. I believe I have narrowed it down to a ground issue with the main relay in the small box with the 2 30amp fuses. When I check pin 85 in the fuse box I do not have continuity to ground. It I put a jumper to to pin 85 in fuse box my issues is corrected. I have a shop manual and referred to the section on testing the main relay ground circuit but it does not get into detail as to where the ground is supplied from. Should pin 85 be grounded at all times ? Thanks for any help.

 

[skiasylum]

The ECM does control that circuit by supplying its ground, but first start/stop switch has to tell the ECM somebody wants to power up the gauges. Your problem is usually solved by replacing the 30 amp relay, then the start/stop switch, which can fail closed so the ECM only sees the shut down phase. By jumping pin 85 you become the ECM.

 

[Seadoojim1]

The ECM does control that circuit by supplying its ground, but first start/stop switch has to tell the ECM somebody wants to power up the gauges. Your problem is usually solved by replacing the 30 amp relay, then the start/stop switch, which can fail closed so the ECM only sees the shut down phase. By jumping pin 85 you become the ECM.

View attachment 62390

I have tested the 30amp relay and found it to good. When I put the key in the post I’m getting nothing on the dash. So if the relay gets its ground control circuit from the ECM should I start at testing the DESS post ?

 

[Seadoojim1]

Ok did some more testing and reporting back. Put in a known good replay same peoblem persists. Did continuity check on start/stop switch. Found normally open position ok button depressed jumping around from 23 ohms to open. So I believe i have a problem there. Did the continuity tests on the DESS post and

 

[skiasylum]

The key and the dess post are just the BRP antitheft protection. You need power to the gauges and start circuit first. If you can't get power to the gauges from momentarily pressing the start button the key and dess are mute. So troubleshoot the relay circuits and start/stop switch and circuit. don't worry about the dess and post yet.

 

[Seadoojim1]

The key and the dess post are just the BRP antitheft protection. You need power to the gauges and start circuit first. If you can't get power to the gauges from momentarily pressing the start button the key and dess are mute. So troubleshoot the relay circuits and start/stop switch and circuit. don't worry about the dess and post yet.

I don’t recall ever being able to get power to the gauges by pressing the start stop button. They only ever woke up with the key was on the post. As stated earlier I’m not seeing a ground coming into pin 85 to energize the relay. What tells the ECM to send a ground to pin 85 of the relay then ?

 

[skiasylum]

Start/stop switch

 

[Seadoojim1]

Start/stop switch

So you’re saying when I put the key on the post and I’m not hearing any beeps or nothing from the dash it can be related to the start/stop switch ? It’s reading normally open like it should

 

[MacSeaDoo]

What he is saying is that putting a key on the DESS post does nothing if you don't wake the machine first with the start/stop button.

To start a seadoo PWC.

1.. Press start stop button to wake the ECU.
2.. The key will then be read by the ECU to enable engine start.

 

[skiasylum]

So you’re saying when I put the key on the post and I’m not hearing any beeps or nothing from the dash it can be related to the start/stop switch ? It’s reading normally open like it should

It definitely can be related to the start stop switch, if it is not testing properly when pressing the button I would definitely try another switch.

 

[Seadoojim1]

I have never had to hit the start/stop button on this machine to “wake it up” put key on post gauges would come alive with 2 beeps from machine. Hit start button ski would start. The issue I’m having is not getting a good ground signal to pin 85 of the relay. The start stop switch is a normally open switch. Pushing the button only closes the circuit. I can bypass the start stop switch with a jumper wire and no change. I put the key on the post right now and get no gauges or no beeps even with the start stop switch disconnected.

 

[MacSeaDoo]

Someone else might have to chime in here as I don't have experience with machines that are older than 2010 so maybe it is different. In the machines I have dealt with, putting the key on the post does nothing. You have to press the start button to wake, then it will read the key. It will say reading key and give you 2 short beeps when it is all good. Pressing the start again will start the machine.

Now the boat is different. You wake the machine up with the key on the DESS, so I am wondering if this was the way it was in your year, or the programming is different in your machine.

 

[Seadoojim1]

This is the circuit in question

 

[skiasylum]

Just checked a 2006 service manual and sure enough putting the key on the dess post wakes the the ski, the gauges and ECM power up. The ECM must then check for the proper key and then switches the ground to the starter solenoid to allow cranking when the start/stop switch is pressed. What year Seadoo changed the start sequence, somewhere after 2006 and before 2010.
So now the dess post, key, and ECM are part of the equation and the start/stop switch is out. You can test the input side of the start system with BUDs software per the 2006 manual. When pin 85 is jumped and the shit works I would think that would eliminate the dess post and key leaving a ECM issue.

 

[Seadoojim1]

Just checked a 2006 service manual and sure enough putting the key on the dess post wakes the the ski, the gauges and ECM power up. The ECM must then check for the proper key and then switches the ground to the starter solenoid to allow cranking when the start/stop switch is pressed. What year Seadoo changed the start sequence, somewhere after 2006 and before 2010.
So now the dess post, key, and ECM are part of the equation and the start/stop switch is out. You can test the input side of the start system with BUDs software per the 2006 manual. When pin 85 is jumped and the shit works I would think that would eliminate the dess post and key leaving a ECM issue.

 

[Seadoojim1]

So I went through the DESS continuity checks again last night and the last part of testing with key on post. Check continuity between female connector (black/purple wire that excited that relay) to black wire on male connector it states a spec of around 0 ohms. I had an open there. It states at that point replace the DESS post. I went ahead and ordered an OEM BRP post and will give that a try. Does anyone know if the pins and seals are included with the post or did I need to source those separate ?

 

[Seadoojim1]

Diagram

 

[Seadoojim1]

Wanted to update. the new DESS post cleared up the problem. Future reference for anyone you will need to source 3 female and 1 deutche connector pins and have the tool to crimp.

 

[only1battman]

@Seadoojim1 does your ski have the 3 or 4 pin DESS post? I seem to be having the same or similar issues to you. Once you replaced the DESS post, you were able to pop the key on and it woke the ski up no problem?
I tried jumping the relay and the ski powers up/wakes up, but then will only start once the key is in and the start/stop button is pressed.

 

[Seadoojim1]

@Seadoojim1 does your ski have the 3 or 4 pin DESS post? I seem to be having the same or similar issues to you. Once you replaced the DESS post, you were able to pop the key on and it woke the ski up no problem?
I tried jumping the relay and the ski powers up/wakes up, but then will only start once the key is in and the start/stop button is pressed.

4 pin dess post. Yes, same thing on my ski. If you jump the relay, it would wake up and then start with the start stop button as long as the key was on the post. After replacing all is good. Perform the continuity checks shown in the manual for DSS troubleshooting and I’m sure you will find some thing like I did.

 

[only1battman]

Perfect! Thanks for the info. That page you posted for the troubleshooting was what i was looking for, i guess i missed it the first 3 times i looked through the manual. I did the continuity checks last night and it fail one wire with a inconsistent reading + high resistance. I assume this is the wire needed to "wake the ski up". new post on the way, will probably fix the issue.

 

[sdriche]

I have a 2009 RXT-X and my DESS went bad as well. Started with the symptoms you described then wouldn't shut off even when you removed the key. Replaced the DESS and no more issues

Mine wakes up by putting the key on the DESS as well.

If i recall the DESS post does 2 things, magnet to wake up the sky and programmed chip to start the ski (I could be wrong but recall reading two functions to the ski when i was diagnosing)