Cayenne code whack-a-mole brake booster error is back
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From: Bluemont VA
As I mentioned in your previous thread, purchase a vacuum gauge to confirm the vacuum is holding steady under load.
The battery dying while testing should not happen. Sounds like the battery is not charging or its defective. You should measure 14V at the jump posts just above idle.
The battery dying while testing should not happen. Sounds like the battery is not charging or its defective. You should measure 14V at the jump posts just above idle.
Last edited by v10rick; Oct 16, 2017 at 05:30 PM.
Thread Starter
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V10rick,
ok, will do. This one look ok?
Where do I tap into the system? I'm assuming I can connect it somewhere close to the master cylinder and snake the tube into the driver's window while driving around?
It charges fine, the battery died because the engine was off with ignition on while reading/clearing codes. Are you supposed to be pulling codes with engine running instead? I thought it was engine off but ignition on.
cheers,
c
ok, will do. This one look ok?
Where do I tap into the system? I'm assuming I can connect it somewhere close to the master cylinder and snake the tube into the driver's window while driving around?
It charges fine, the battery died because the engine was off with ignition on while reading/clearing codes. Are you supposed to be pulling codes with engine running instead? I thought it was engine off but ignition on.
cheers,
c
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From: Bluemont VA
The Amazon gauge will work as long as it has the adapters to plug into the vacuum line.
If there are no leaks the vacuum should read the same anywhere you connect the gauge. Just pumping the brake pedal while parked should be enough to diagnose what is going on.
I have used my Durametric scan tool for over an hour with the ignition on and the engine off with no issues.
The battery should not drain while reading codes all day long.
If there are no leaks the vacuum should read the same anywhere you connect the gauge. Just pumping the brake pedal while parked should be enough to diagnose what is going on.
I have used my Durametric scan tool for over an hour with the ignition on and the engine off with no issues.
The battery should not drain while reading codes all day long.
Last edited by v10rick; Oct 16, 2017 at 05:29 PM.
Three Wheelin'
Joined: Aug 2016
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Mine recently died. Replaced at $218.30 from this guy. All better. Assume the guy who knew the corresponding Audi part paid less.
http://www.ebay.com/itm/Porsche-Caye...72.m2749.l2649
http://www.ebay.com/itm/Porsche-Caye...72.m2749.l2649
Thread Starter
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Joined: Jun 2017
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cheers,
c
Thread Starter
Pro
Joined: Jun 2017
Posts: 552
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Ordered the OTC vacuum/pressure gauge:
Also ordered the mityvac vacuum pump kit:
Gauge is here tomorrow, so going to try to get this properly diagnosed rather than just ordering the vac pump (although I'm pretty sure it's the pump). This will also let me fix some vacuum leaks on the 968 that I know exist, but that I've never gotten around to. Something about staring at a bid red warning message every time you drive that really motivates in the Cayenne. Amazing to me that Germans have always made crap vacuum and fuel lines going back to post WW2 era (I used to collect old VW's). Yet somehow, they make great A/C lines. My 968 is 24 years old and has absolutely frigid air conditioning even on 120F Phoenix days, never had service of any kind, never even been recharged.
cheers,
c
Also ordered the mityvac vacuum pump kit:
Gauge is here tomorrow, so going to try to get this properly diagnosed rather than just ordering the vac pump (although I'm pretty sure it's the pump). This will also let me fix some vacuum leaks on the 968 that I know exist, but that I've never gotten around to. Something about staring at a bid red warning message every time you drive that really motivates in the Cayenne. Amazing to me that Germans have always made crap vacuum and fuel lines going back to post WW2 era (I used to collect old VW's). Yet somehow, they make great A/C lines. My 968 is 24 years old and has absolutely frigid air conditioning even on 120F Phoenix days, never had service of any kind, never even been recharged.
cheers,
c
Three Wheelin'
Joined: May 2012
Posts: 1,635
Likes: 375
From: Mid-Atlantic
Mine recently died. Replaced at $218.30 from this guy. All better. Assume the guy who knew the corresponding Audi part paid less.
http://www.ebay.com/itm/Porsche-Caye...72.m2749.l2649
http://www.ebay.com/itm/Porsche-Caye...72.m2749.l2649
Kind of a pisser. It's not a big deal, but there shouldn't be a price point where I'm too lazy to avoid getting ripped off. I got lazy on that one and didn't even look for a VW or Audi part number. Did you post this up somewhere? It's great when people post up the two corresponding part numbers so it's easily searchable.
Rennlist Member
Joined: Sep 2009
Posts: 1,649
Likes: 125
From: Bluemont VA
Ordered the OTC vacuum/pressure gauge:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Also ordered the mityvac vacuum pump kit:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Gauge is here tomorrow, so going to try to get this properly diagnosed rather than just ordering the vac pump (although I'm pretty sure it's the pump). This will also let me fix some vacuum leaks on the 968 that I know exist, but that I've never gotten around to. Something about staring at a bid red warning message every time you drive that really motivates in the Cayenne. Amazing to me that Germans have always made crap vacuum and fuel lines going back to post WW2 era (I used to collect old VW's). Yet somehow, they make great A/C lines. My 968 is 24 years old and has absolutely frigid air conditioning even on 120F Phoenix days, never had service of any kind, never even been recharged.
cheers,
c
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Also ordered the mityvac vacuum pump kit:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Gauge is here tomorrow, so going to try to get this properly diagnosed rather than just ordering the vac pump (although I'm pretty sure it's the pump). This will also let me fix some vacuum leaks on the 968 that I know exist, but that I've never gotten around to. Something about staring at a bid red warning message every time you drive that really motivates in the Cayenne. Amazing to me that Germans have always made crap vacuum and fuel lines going back to post WW2 era (I used to collect old VW's). Yet somehow, they make great A/C lines. My 968 is 24 years old and has absolutely frigid air conditioning even on 120F Phoenix days, never had service of any kind, never even been recharged.
cheers,
c
Compared to the NA engine this should be easier to diagnose. #4 are check valves, one or more could be leaking.
The turbo engine brake booster vacuum is supplied by both the engine manifold vacuum and pump. The pump is a booster when the manifold vacuum falls below a fixed threshold. The booster pump should NOT run while parked, assuming no leak, the engine is warm and parked near sea level.
To diagnose...
With the engine off pull the manifold vacuum line and connect the Mityvac there. Pump vacuum to the max, the reading should remain stable. If not check for a leak or defective check valve.
With engine off pull the vac line to the pump and connect the Mityvac there. Pump to the max, the reading should be stable. If not same as above.
With the engine off pull the line to the brake booster and connect the Mityvac there. Plug both the line to the engine manifold and booster pump with a golf T or ? and pump the Mityvac to the max. The reading should remain stable.
Let us know the results.
Last edited by v10rick; Oct 16, 2017 at 10:43 AM.
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Three Wheelin'
Joined: Aug 2016
Posts: 1,682
Likes: 70
Kind of a pisser. It's not a big deal, but there shouldn't be a price point where I'm too lazy to avoid getting ripped off. I got lazy on that one and didn't even look for a VW or Audi part number. Did you post this up somewhere? It's great when people post up the two corresponding part numbers so it's easily searchable.This is the Audi part number:
8E0927317A
This pump is utilized extensively in their line from the A4, A6, A8, S5 to the Q7 (sister of the Cayenne) so you should find a ton of cheap used ones or sale. I can't remember if mine was used and the auction page is no longer available, but it is possible. It's been working like a charm.
It might help you find the VW part number. Someone really needs to develop a reliable cross reference system. It is pretty absurd that for example diverter valves for VW are $18 and for Porsche they are $60 for the exact same part!
Three Wheelin'
Joined: May 2012
Posts: 1,635
Likes: 375
From: Mid-Atlantic
Rennlist Member
Joined: Sep 2009
Posts: 1,649
Likes: 125
From: Bluemont VA
I posted the brake system diagram and theory of operation on your other thread about this.
Look there for trouble shooting suggestions.
Two threads from a poster about the same problem often leads to confusion.
Last edited by v10rick; Oct 16, 2017 at 09:28 AM.
Rennlist Member
Joined: Sep 2009
Posts: 1,649
Likes: 125
From: Bluemont VA