Multiple Fault Codes - Ecu Or Wiring?

[filipharvey 0]

Was expecting it to be the flexi, but no, the actual pipe has split all the way around the weld.

[smiffy 99]

:eek:

Well if they still have them the flexis are near brand new, I only changed them cus of cf2's being fitted to the GTA

[filipharvey 0]

I'll have them off you if you can find them. I'll probably be able to get these patched up for now, but the flexis weren't brilliant when I bought them from AL, so a spare set will be handy.

[filipharvey 0]

Well the exhaust splitting may well have been a good thing!

During all my fiddling around, I had only checked and cleaned connections, not the wires themselves. Whilst I was under the car removing the downpipe, I noticed that the front in-cat lambda wire was split - both white wires. Those are the two that power the lambda heater, and by the looks of it they had been touching where the bare wires met.

I'm gonna take a wild guess, but I reckon this is the cause of all my problems.

 

So, what I need to know is;

 

a ) Where is the fuse for the lambda heaters?

b ) Is that fuse shared with the MAF or EVAP control?

 

I've checked most of the fuses above the main fuse box by the driver's knee, but they all seemed fine.

I'm hoping that there is actually a fuse for them, otherwise this will definitely have goosed the ECU!

Edited April 8, 2013 by filipharvey

[filipharvey 0]

Well it is all back together and the fault is still there, so it must be a fuse, relay or the ECU.

 

Does anybody know where that fuse/relay is???

[Smaky 73]

Swaping the ECU wont allow the engine to run as you need the code box and chip too, and if it's fried one ECU then it will fry another.

 

The Lambdas don't have a fuse, it's a sinal from the ECU to a relay which switches on the 12V for the heater, any fault in that cicuit and the ECU should cut the signal thus cutting the 12V. And yes the MAF is affected by the lambdas if there are wiring shorts as they all share a common earth and back voltage then becomes an issue causing excessive fueling. Replacing the Lambda is the only course of action and possibly the MAF too, realy though I need tis one hands on to diagnose properly.

[filipharvey 0]

I'm aware the engine won't start, but my thinking was that as the fault shows even with the engine off, and reappears as soon as plug B is reconnected to the ECU (it won't clear with it connected) then I don't need to go as far as starting the engine with a different ECU.

However, if you think there is a chance of blowing another, I won't try it.

I do think that the shorting lambda wires are the likely cause though, and that has been sorted.

I have swapped all of the relays in front of the battery around, and the fault still shows.

I know you really need to see it hands on, but you are a long way from me. Is there anything else I should be looking for diagnostic wise?

[Smaky 73]

I think it's not worth trying, If the ECU isn't blown and you've sorted the wiring and is it clearing when unplugged on your ECU?

 

 

And I've just read right through again... have you tried another MAF yet or checked the earth connection for all the sensors and ECU next to the oil filler cap?

 

 

And should you ever feel like a trip to Oxford, I have a full ME3.1 ECU set here which I use on these occasions.

Edited April 11, 2013 by Smaky

[filipharvey 0]

I think it's not worth trying, If the ECU isn't blown and you've sorted the wiring and is it clearing when unplugged on your ECU?

If the lambda alone is unplugged, no it doesn't clear. Plug B has to be removed from the ECU itself for the fault to clear.

 

 

And I've just read right through again... have you tried another MAF yet or checked the earth connection for all the sensors and ECU next to the oil filler cap?

Yes, have tried another MAF. The ECU is earthed to the body as it was relocated to the bulkhead when I put the 3.0 in. The earth leads to the block and cam covers are good too. Not sure where to check the earths to the sensors themselves though?

 

 

And should you ever feel like a trip to Oxford, I have a full ME3.1 ECU set here which I use on these occasions.

Thanks mate

[Smaky 73]

OK, plug B, this also does the coil packs, and where the wires run under the coil covers the plastic goes brittle, snaps off the looms and leaves the wiring rubbing the covers, these could be earthing and causing the problem too, I've had that one before, and unpluging B is proving your ECU is fine, so there is another loom issue somewhere.

[Smaky 73]

I'll be at SAD if your going...

[filipharvey 0]

Ok, well the front cover is off - has been for some time. I'll take the plenum off tomorrow and check for any signs there.

 

Unlikely that I'll be at SAD.

Edited April 11, 2013 by filipharvey

[filipharvey 0]

Just removed plenum, no sign of split wires there. If I disconnect all 4 lambdas, the faults still say invalid signal - surely it should change to no signal?

Only the precat lambda on bank 2 changed its status to that.