550 intermittent limp mode, ASR error, no RPMs

I have been fighting a asr/abs issue also. I'v sent my computers out and came back fine. I lost all guages and speedo and tack
I'm now getting 4 codes 1674,1675 (same) 1538,1631 and PO460 .I think it is in the CAN system. maybe left side fuel sensor ?
Checked all fuses related. anyone have any thoughts. I have a 02 575 . had my ASR/ABS module repaired already.
Love some help ,much thanks Dino

 

Interesting. On first impression it sounds like an instrument power problem, but let's do a quick review of signal paths.

The ABS/ASR computer sends speed data directly to the Digitek unit (the digital display in the binnacle) on a single wire (no CAN Bus), via instrument panel plug "B". The Digitek unit processes the signal from the ABS/ASR computer and sends it to the Speedo. It also sends the signal to other components (power steering, engine ECUs, etc).

The tacho signal (as previous stated) comes from one of the engine ECUs and via a number of splices and instrument panel (plug "A") to the tacho. Again it is a single wire. No CAN Bus involved. The tacho and speed signal wiring is independent. There is one single connector on the 550 I can recall where both tacho and speed data is present, but even if this plug was disconnected, it wouldn't affect the gauges. For info, it's called the Engine Signals Connector and is found to the right of the fuse panel (4 pin plug).

I really think we should focus on instrument power. As you say, you've checked fuse 5, so we need to trace the wiring from that fuse.

Here's the diagram:

https://www.dropbox.com/t/TYe1rNHPP33PtHrQ

If you follow the wire from the "bottom" of fuse 5, it goes to relay panel plug J (pin 6). The output is split into two green/white wires. One goes to splice "199". This feeds a lot of stuff, including the instrument panel. It basically powers all the main instrument panel gauges. It also powers the oil temp gauge in the centre instrument cluster. The fuel gauge in the centre instrument cluster seems to be powered by the Digitek unit. I'm currently trying to figure out what powers that.

The good thing about the 550 is that it is easy to check the relay panel outputs. I would be checking the voltage on plug J, pin 6 (with the ignition on).

Anyway, I'll give you some time to catch up with what I've said

 

For info, the Engine Signals Connector mentioned above also carries instrument gauge power. If the wiring for that has been crushed and shorted together, it does have the potential to take out all the gauges. It is shown in the wiring diagram (plug 23D) in the lower RH corner of the diagram. It's an unlikely scenario, however.

 

There is a mini graphic in my wiring diagram (above) showing the plug numbering, but here it is by itself:

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As always, my wiring diagram hyperlinks self-destruct in 6 days. Cue Mission Impossible theme song

 

oops.. missed the fine print. Disregard all of the above. I thought we were talking about the 550 (thread creep). If it's a 575, then CAN bus issues are back on the table. Since there are no wiring diagrams for the 575, I might have to find insight from the setup on the F360.

 

... unless Taz has some diagrams?

So you've even lost the analog gauges such as oil temperature and pressure? (and fuel) i.e. non-CAN Bus data.

There are usually two power sources for this generation display. Power comes into the instrument panel on a 12 pin plug. Live battery ("+30") power on pin 1, key ("+15") power on pin 2. Fuse F16 and fuse F34 provide power on the 575.

Since I don't have any wiring diagrams, the only place to check for power will be on the 12 pin plug. See plug "B"

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Since power and a few of the analog gauge signals go through this plug, perhaps the plug is not connected properly?

The plug shown in the inset/box (in the above diagram) is the wiring harness plug as seen from the contact side, not the wire side).

 

Ian- There is probably an expanded 575M section L out there somewhere, but I have not seen it. The only thing in the WSM is the 30 amp F16 fuse in Box C and the 15 amp F34 fuse in Box D.