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ATTESSA and pressure switches

MrStabby
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MrStabby Grand Master

MrStabby

Posted
Posted

Looks like both of my cars have pressure switch issues.

The R32 GTR has 18 flashes on the ATTESSA controller which is "ETS pressure switch circuit". The 4WD light is intermittent, and often just restarting the car clears it. There is an $300 replacement option https://www.ebay.com.au/itm/285675135148?itmmeta=01HXN3YKRGKQ08GRZ5KFKKZWJT&hash=item428390a0ac:g:6CcAAOSwWxBltMEG so if it becomes a permanent issue and I can confirm that the switch is the issue, i have a solution.

The NM35 is reporting C1208, and disconnecting the switch causes the 4WD light to go away. Translating from the Japanese shop manual
"when the pressure is reduced to 2.6MPa (377 psi) or less: conduction occurs
when the pressure increases to 3.8MPa (550 psi) or less: conduction is present.

Reference: • Immediately after the E-TS actuator motor stops, the pressure inside the
accumulator is high and there is no continuity."

Not sure how good the translation is but from what i can deduce this means the switch is normally closed (NC) and as the pressure builds from 0 to 550 psi the switch stays closed, then opens and 550 psi. As the pressure drops from 550 psi to 377 psi the switch stays open then closes again at 377 psi. Is that how these things work?

These pressures are a lot higher than the R32 ("control pressure 0-228 psi") but i'm hoping i can find a generic switch (like they've done for the R32) to use as a replacement. Maybe something like https://www.ebay.com.au/itm/355586397452?epid=1676016964&itmmeta=01HXN534AF22ACTG6TGDDQGEQ7&hash=item52ca99d50c:g:mAEAAOSw8ilmBcMh&itmprp=enc%3AAQAJAAAA8LtWdNlWHgyJ%2F3cbw25S2A1lde3qBi3fJii4T3lQavCz4kpqiD42SmBa4FocMvXCjcxiowHjb8vZ8%2BWxc53BkHv781tkStSnCDaenfGKC3bIp0keK20dfsn9LoPa3TfqaEmAydqqyKobgTdXsGGzsl%2BRjOVGuD8OIpOv%2B0wMl7aUtHg0iJtojbtzA%2BRS8Xfm8Ufjuvz4niwrqglAXFUbkL6J%2FGuHPeeECZhLBBN3iNM1Swl94Fv5zE95YK%2B5O6dxDN1ySNOjdMxkA8yaprbuwRHFQv1nlGh%2FWjekj6EUFR2%2FO4HTsoKtSAkY0Mj1w1uf1w%3D%3D|tkp%3ABk9SR6zFjKXtYw but with a lower close pressure, and thread adapter if required.

Am i dreaming?

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blind_elk Grand Master

blind_elk

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I had a similar situation with my R32 GTS4. I replaced that solenoid, but it hasn't solved the problem. So its possible the pump is failing.

It seems you need to drop the diff in order to do anything that might fix this. So its important to know exactly what the problem is. Or just replace / repair everything while the diff is out.

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Duncan Grand Master

Duncan

Posted
Posted
19 hours ago, MrStabby said:

Not sure how good the translation is but from what i can deduce this means the switch is normally closed (NC) and as the pressure builds from 0 to 550 psi the switch stays closed, then opens and 550 psi. As the pressure drops from 550 psi to 377 psi the switch stays open then closes again at 377 psi. Is that how these things work?

Yeah exactly the switch unit just needs to be designed with those numbers (or thereabouts, obviously the high one is the more dangerous if you don't get it right).

It would be worth contacting FPG, they are pretty responsive and might be able to add to their lineup with you M35 information, the have 80% sorted already from the GTR one. https://frenchysperformancegarage.com/

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MrStabby Grand Master

MrStabby

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12 hours ago, blind_elk said:

I had a similar situation with my R32 GTS4. I replaced that solenoid, but it hasn't solved the problem. So its possible the pump is failing.

It seems you need to drop the diff in order to do anything that might fix this. So its important to know exactly what the problem is. Or just replace / repair everything while the diff is out.

Ok so the other test that seems easy enough (with the right equipment) would be to check what pressure the pump produces when its on. If its in spec its probably safe to just replace the pressure switch, and if not it makes sense to replace the whole unit.

Does that sound sensible?

EDIT: Do you have a spare pressure switch you want to sell?

Duncan Grand Master

Duncan

Posted
Posted

Yeah that sounds like a way to isolate the issue, but I am not sure how easy it is to get a gauge on it; as Greg said it is subframe out to do anything anyway.

As it happens FPG also have a attesa pressure sender which goes in the rear of the xfer case. I have a kit but have not installed in the race car yet (because, race car)

https://frenchysperformancegarage.com/collections/nissan-skyline-r32gt-r/products/fpg-bnr32-attesa-high-pressure-hose-replacement-with-optional-pressure-sensor-adapter-fpg-116

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