512TR Secondary Air valve Fault code

one of the banks on my 512TR is producing a fault code 1123 (Secondary air solenoid valve). this is straight out of the right bank computer. The other bank has no fault codes.
Looking at the attached diagram, I figure probably one of the air valves is faulty and dumping air into the other bank (I have had a slow down light on the RHS Bank as well, but its intermittent).

So what I did was disconnect the pipes (on both banks) between valves O and M (see attached), so no air can be feed in, as well as no cross bleeding can happen (if one of the valves is faulty). Clear the computer from fault codes and start her up again.
NO Change. Its still producing the same fault code on RHS bank, and none on the other side.

Q: How is the computer working this out? as in, a secondary valve is faulty. The only input to the computer (that could have something to do with this) really is via the O2 sensor. True?
Q: when it says Secondary air solenoid valve, which valve does it mean? none on the diagram are indicated as a Secondary air solenoid valve.

I think I am close to working this out, but would like an opinion if possible from the wider audience.
It could be the O2, but I have run the car with both O2s disconnected (running open loop) with no change.

Any ideas?
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Thanks guys. I was going to block the check valves if I ended up getting the error code on both banks (since I disconnected on both sides). But since that didn't happen, I will persue the solenoid.

One more point (up for discussion later), is that both check valves are letting small amount of exhaust out. I wouldn't have expected that as they are one way valves designed to let air injection in. They could be faulty, but doesn't look like its causing any issues at the moment.

I love this diagnostic banter

 

Ok. I disconnected the good side solenoid, and sure enough, the LHS error code shows up. Good.
I then connect the RHS solenoid to the LHS connector, and the LHS fault code disappears.
This shows that both solenoids are fine.
There must be a break in the wire on the RHS to the RHS computer. Oh joy. The tracing begins
Will look at the schematics to see what pins on the ECU these come in on.
I don't think any of this is causing any issues in running the engine, it's just the annoying fault code.

New fault though, the secondary air pump is seized, producing a high load on whatever it's connected too. I am surprised this hasn't blown a fuse or cooked a driver circuit in the ECU. I will have to check this later.
Q: how is the motor attached to the fan on the air pump? Is it just press fitted on? Any clues on how to pull the blades off the motor shaft?

 

Oh yes, I have done that also.
I checked out the schematics, and these solenoids go straight to the ECU, and the other side to an earth block. Will check the earth block

Yes I have the motor apart, will post some photos. I also checked the schematics for this, and it has its own fuse, so fingers crossed, it would have blown the fuse. I have a feeling that the fault code could also be calling out this motor. As its only one motor, it would only be connected to one of the ECUs. I had a quick look to see if its triggered with the same pin as the RHS solenoid, but I dont think so (thought engineers may have done something dodgy and hooked them up together since they needed a ECU signal from one of the ECUs .

 

similar to this.
Seriously, the motor in that thing looks like something from a hair dryer.
Absolute rubbish. to even think to charge $1100 for this is nothing short of criminal.
will post internals tonight.
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Ok, so how do I separate the fan from the motor shaft?
It looks press fitted on.
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Unfortunately, on Page L23 of the Schematics, its missing a critical piece (where the photocopy was done badly) between the fuse box and connector 41051, Pin 12.
I cant tell what happens to the Pin 12 and where it goes in the fuse box. The Solenoid on this side doesnt go straight to the ECU. it goes to the fuse box first. Damn....
But looks like there is a relationship between the solenoid and the air pump on the bank 1-6.


I dont suppose someone has a better schematic out there?

I may fake the air pump connection to complete the circuit and see what happens to the error code.

 

Lots of resolved issues tonight.

If you check out the schematics attached, apart for the fact that they dont link up properly, so had to guess a few things. The upshot of it is that Relay V, supplies both the Air Pump (01407) and the 1-6 Secondary air solenoid (connector 41051 pin 12). The Relay is driven via Pin 32 of the ECU (I so love the Motronics 2.7) which goes back via connectror 41051 (pin 14).
With the Air pump seized, it was blowing Fuse 8. So the relay was removed, causing the ECU to fault (no path back to Pin 32).
So now Air pump removed, relay back in, NO MORE FAULT. Woooo.

And on a still positive note, the impeller can be removed via a 2mm hex grub screw (if you look carefully towards the center of the impeller, you can just make out a cutout in the blade). So motor can be removed for reconditioning, hopefully.
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more news on the motor. I decided to pull it apart, thinking that the bearings were shot (it was very hard to turn).
as you can see from the photos, it had overloaded and one of the wires blew, lodging itself between stator and rotor. thats why it was hard to turn.
Luckily, this wire was the commutator return wire. I figure with nothing to loose, I unwound about 10cm to give me enough lenght to take it back to the commutator.
the wire are held in there by compression from a tab. see pics.
lodged the wire in, pressed the tab, put the motor back together.
And presto, it fires up. All done.
I figured the compressor blade is touching the housing (cause its doing it now) and thats what overloaded the motor. I will be putting a thin gasket on the impeler housing to separate it a bit, and it will work fine.
Again, this was really an exercise in time wasting. I wont be putting this air pump back in the car.
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No, as long as the relay is in, it's fine.
There is no way the motronic can drive the motor directly, so it drives the relay, which in turn connects the solenoid and motor.
The ECU only sees the relay coil for bank 1 to 6

Eventually will remove the electro valves, once I can seal the exhaust check valves.
Currently when the solenoids engage, they just pass unpressurised air. No big deal.

QUOTE=dontilgon;141658604]So being the airpump is disconnected , are not getting faulty codes? Also will you be disconnecting the electrovalves?[/QUOTE]

 

It seems I couldnt reply to your PM (you seem to be blocked from receiving anything)

anyways, here is the response:

I disconnected the pump only, not the relay.
This is only used to heat up the cats, nothing else, so I have no cold start problems whatsever without the pump.
But leave the relay in, as it controls the bank 1-6 solenoid, and without it, will generate an ECU fault.

Hope this helps.

 

well you cant remove solenoids R. You must leave them, and block the line that goes to O. Youll get a vacuum leak to the manifold if left open.

Otherwise you can remove everything else, and block at L or M.

And leave the relay in place.

That should do it.