Another strange electrical fault (2004 Cayenne)
05-15-2018 | 02:42 AM
#17
Thread Starter
Advanced
Joined: Mar 2016
Posts: 69
Likes: 2
Yes, sorry, I keep meaning to post but life's a bit hectic. Thanks for the reminder!
I had a new battery fitted - a Yuasa YBX5020 - after my last post and so far... all good. Starts every time, no problems at all. So I think it's safe to say my last bit of work (disconnecting the head unit) was what finally stopped the drain, it was just the battery was already dead from all the starts.
I still have a PSM failure sign but I've not got around to trying the reset (moving the wheel then driving straight forward). I'll do that and if it doesn't clear, I'll get to a garage (the garage who fitted the battery has test equipment but it was being repaired).
Then I need to fix the parking brake light that comes on a lot now ( 955 423 389 00 I believe).
And finally, put a replacement head unit it - and we're good to go! (Well, I'm going ok now, just having to use my phone for music/podcasts).
Thanks everyone for the help and sorry it took a prompt to post the outcome.
I had a new battery fitted - a Yuasa YBX5020 - after my last post and so far... all good. Starts every time, no problems at all. So I think it's safe to say my last bit of work (disconnecting the head unit) was what finally stopped the drain, it was just the battery was already dead from all the starts.
I still have a PSM failure sign but I've not got around to trying the reset (moving the wheel then driving straight forward). I'll do that and if it doesn't clear, I'll get to a garage (the garage who fitted the battery has test equipment but it was being repaired).
Then I need to fix the parking brake light that comes on a lot now ( 955 423 389 00 I believe).
And finally, put a replacement head unit it - and we're good to go! (Well, I'm going ok now, just having to use my phone for music/podcasts).
Thanks everyone for the help and sorry it took a prompt to post the outcome.
05-15-2018 | 02:51 AM
#18
Instructor
Joined: Oct 2017
Posts: 112
Likes: 1
From: CA
Yes, sorry, I keep meaning to post but life's a bit hectic. Thanks for the reminder!
I had a new battery fitted - a Yuasa YBX5020 - after my last post and so far... all good. Starts every time, no problems at all. So I think it's safe to say my last bit of work (disconnecting the head unit) was what finally stopped the drain, it was just the battery was already dead from all the starts.
I still have a PSM failure sign but I've not got around to trying the reset (moving the wheel then driving straight forward). I'll do that and if it doesn't clear, I'll get to a garage (the garage who fitted the battery has test equipment but it was being repaired).
Then I need to fix the parking brake light that comes on a lot now ( 955 423 389 00 I believe).
And finally, put a replacement head unit it - and we're good to go! (Well, I'm going ok now, just having to use my phone for music/podcasts).
Thanks everyone for the help and sorry it took a prompt to post the outcome.
I had a new battery fitted - a Yuasa YBX5020 - after my last post and so far... all good. Starts every time, no problems at all. So I think it's safe to say my last bit of work (disconnecting the head unit) was what finally stopped the drain, it was just the battery was already dead from all the starts.
I still have a PSM failure sign but I've not got around to trying the reset (moving the wheel then driving straight forward). I'll do that and if it doesn't clear, I'll get to a garage (the garage who fitted the battery has test equipment but it was being repaired).
Then I need to fix the parking brake light that comes on a lot now ( 955 423 389 00 I believe).
And finally, put a replacement head unit it - and we're good to go! (Well, I'm going ok now, just having to use my phone for music/podcasts).
Thanks everyone for the help and sorry it took a prompt to post the outcome.
05-15-2018 | 10:11 AM
#20
Instructor
Joined: Jun 2016
Posts: 207
Likes: 1
From: Portland, Ontario
Another point about the electrical drain. My retired-electrican friend kept complaining about his Dodge Journey killing its battery. The dealer kept replacing them under warranty until finally Les cleaned out his glove box and discovered a forgotten 12v to 115 v device which had been steadily drawing power. Since he unplugged it, there have been on more electrical glitches with the Journey.
Last edited by Rod Croskery; 07-30-2018 at 11:32 AM.
05-15-2018 | 07:45 PM
#21
Burning Brakes
Joined: Jun 2009
Posts: 1,163
Likes: 142
From: Bay Area, CA
Regarding the second, auxiliary battery that may or may not be in the trunk ...
From checking the service manual for my 2004 S, you will have one of two things in your trunk:
Either
1 - a collapsible spare tire on top of a Bose subwoofer
Or
2 - No spare tire at all. You do get a tube of tire sealant, though. And a subwoofer on top of the auxiliary battery.
So if you have the collapsible spare tire (like I do, and is the more common of the two options), you do not have the auxiliary battery. No need to remove the subwoofer to check.
If you don't have the collapsible spare tire, either someone took it, or you've got an auxiliary battery under the subwoofer.
From checking the service manual for my 2004 S, you will have one of two things in your trunk:
Either
1 - a collapsible spare tire on top of a Bose subwoofer
Or
2 - No spare tire at all. You do get a tube of tire sealant, though. And a subwoofer on top of the auxiliary battery.
So if you have the collapsible spare tire (like I do, and is the more common of the two options), you do not have the auxiliary battery. No need to remove the subwoofer to check.
If you don't have the collapsible spare tire, either someone took it, or you've got an auxiliary battery under the subwoofer.
05-15-2018 | 08:34 PM
#22
Pro
Joined: Jun 2017
Posts: 516
Likes: 79
From: UK
From personal experience, if you have kessy and your battery goes flat because your kids left the door open all night, remove the plastic key, insert the normal metal one and it will start. No idea if it uses the second battery or not.
Genius!
more info here but it doesn't really explain what happened above:From the 2004 Cayenne Technik Book...
"Battery
Depending on specification and air-conditioning zones, the Cayenne is fitted with a battery having a capacity of 340 A/70 Ah to 450 A/95 Ah. As on the Cayenne S and Cayenne Turbo, the alternator is water-cooled and has a nominal output of 2100/2660 watts, depending on battery capacity. All Cayenne models can optionally be equipped with a backup battery (starter battery). This backup battery ensures that the vehicle can still be started even if the vehicle battery (main battery) is discharged. The capacity of the backup battery is 480 A/85 Ah.
If two batteries are fitted to the vehicle (main battery and backup battery), these are connected or disconnected to the bus bar in the power distributor through a relay. The switching of the two batteries is controlled independent of the load management (function is integrated in the vehicle electrical system control unit). The starter relay of the 2nd battery is actuated parallel to the starter relay. That means for every start the starter is supplied from both batteries. The backup battery is disconnected from the vehicle electrical system when the engine is switched off and then supplies just one consumer, the vehicle electrical system control unit.
For crash protection purposes, the backup battery is designed using fleece technology.
Note: The backup battery is accommodated in the spare wheel recess in the trunk. This installation location is also designated for the optionally available collapsible spare wheel and the subwoofer of the BOSE® High End surround sound system. This results in a restricted storage capacity in the spare wheel recess. On the Cayenne, the optional backup battery cannot be fitted in conjunction with a 17" collapsible spare wheel.
In order not to exceed the maximum permitted rear axle load, no Cayenne model can simultaneously be equipped with the backup battery, a full-size spare wheel on the external holder and a trailer towing device.
Vehicle electrical system control unit
On vehicles with two batteries (vehicle electrical system and starter battery), the electronics of the vehicle electrical system control unit are supplied by both batteries. The vehicle electrical system control unit evaluates the exact vehicle electrical system situation by comparing the sensed voltage with the permissible minimum voltage. On vehicles with two batteries, the load management always takes the voltage of the vehicle battery as reference. If the vehicle electrical system control unit detects a critical battery condition,
the consumption is reduced. For this the CAN bus requests some of the high voltage comfort consumers to reduce or switch off their power demand. By reducing the comfort functions with the “engine running”, the battery can be charged more. With the “engine off”, discharging of the battery can be reduced through the load management.
Currently the following consumers are integrated in the load management:
• Heated rear window, heated outside mirrors
• Heated seats, front and rear
• Heated steering wheel
• Heater blower (3-stage)
• Interior light, reading lamps, footwell lighting
• 12 V sockets
The following functions are activated by the vehicle electronic system control unit:
• Load management
• Side marker lights
• Low beam
• Cornering light, left and right
• High beam
• Auxiliary high beam
• Direction indicator light
• Headlamp leveling control
• Potentiometer convenience lighting terminal 31
• Terminal 58 d
• Interior and footwell lights
• Fanfare horns
• Dual washing pump
• 12 V sockets
• Electric fuel-pump relay 1
• Load relay
• Rain sensor
• Enable signal, heated seats"
Genius!
more info here but it doesn't really explain what happened above:From the 2004 Cayenne Technik Book...
"Battery
Depending on specification and air-conditioning zones, the Cayenne is fitted with a battery having a capacity of 340 A/70 Ah to 450 A/95 Ah. As on the Cayenne S and Cayenne Turbo, the alternator is water-cooled and has a nominal output of 2100/2660 watts, depending on battery capacity. All Cayenne models can optionally be equipped with a backup battery (starter battery). This backup battery ensures that the vehicle can still be started even if the vehicle battery (main battery) is discharged. The capacity of the backup battery is 480 A/85 Ah.
If two batteries are fitted to the vehicle (main battery and backup battery), these are connected or disconnected to the bus bar in the power distributor through a relay. The switching of the two batteries is controlled independent of the load management (function is integrated in the vehicle electrical system control unit). The starter relay of the 2nd battery is actuated parallel to the starter relay. That means for every start the starter is supplied from both batteries. The backup battery is disconnected from the vehicle electrical system when the engine is switched off and then supplies just one consumer, the vehicle electrical system control unit.
For crash protection purposes, the backup battery is designed using fleece technology.
Note: The backup battery is accommodated in the spare wheel recess in the trunk. This installation location is also designated for the optionally available collapsible spare wheel and the subwoofer of the BOSE® High End surround sound system. This results in a restricted storage capacity in the spare wheel recess. On the Cayenne, the optional backup battery cannot be fitted in conjunction with a 17" collapsible spare wheel.
In order not to exceed the maximum permitted rear axle load, no Cayenne model can simultaneously be equipped with the backup battery, a full-size spare wheel on the external holder and a trailer towing device.
Vehicle electrical system control unit
On vehicles with two batteries (vehicle electrical system and starter battery), the electronics of the vehicle electrical system control unit are supplied by both batteries. The vehicle electrical system control unit evaluates the exact vehicle electrical system situation by comparing the sensed voltage with the permissible minimum voltage. On vehicles with two batteries, the load management always takes the voltage of the vehicle battery as reference. If the vehicle electrical system control unit detects a critical battery condition,
the consumption is reduced. For this the CAN bus requests some of the high voltage comfort consumers to reduce or switch off their power demand. By reducing the comfort functions with the “engine running”, the battery can be charged more. With the “engine off”, discharging of the battery can be reduced through the load management.
Currently the following consumers are integrated in the load management:
• Heated rear window, heated outside mirrors
• Heated seats, front and rear
• Heated steering wheel
• Heater blower (3-stage)
• Interior light, reading lamps, footwell lighting
• 12 V sockets
The following functions are activated by the vehicle electronic system control unit:
• Load management
• Side marker lights
• Low beam
• Cornering light, left and right
• High beam
• Auxiliary high beam
• Direction indicator light
• Headlamp leveling control
• Potentiometer convenience lighting terminal 31
• Terminal 58 d
• Interior and footwell lights
• Fanfare horns
• Dual washing pump
• 12 V sockets
• Electric fuel-pump relay 1
• Load relay
• Rain sensor
• Enable signal, heated seats"
05-27-2018 | 08:21 AM
#23
Thread Starter
Advanced
Joined: Mar 2016
Posts: 69
Likes: 2
Hi all,
The problem has just returned
It's been working perfectly for over a month - no problems at all, not felt any slow starts or anything. And then yesterday it was totally dead. The doors opened with the fob, but that was it. Nothing at all. Wouldn't even shut without using the key manually.
I'd blown my multimeter recently so I couldn't test it, but got another last night.
I've just been to test it. The voltage was 3.5 or so.
So I used my Hummer jump start pack and it started ok, and went for a drive. I have to go somewhere soon so I couldn't do a long drive, but I needed to pop to a local shop so I drove for maybe 15 minutes and stopped (the shop isn't that far, I went a long way).
I popped in to the shop (5 minutes) and returned. Before I started the car (but after opening it with the fob), I tested the voltage and it was about 12.48?
How could it possibly go from 3.5 to 12.5 with a 10 or 15 minutes drive?
I drove home, another 5 minutes or so, and got out and checked it again. It was about 12.56. The inside lights were still on so I shut the doors, and locked them. All the lights went out.
I stood there for 15 minutes and watched as the voltage slowly dropped to 12.38.
Any thoughts please? How could it be fine for a month and then stop? How could it go from 3.5 to 12.5v in 10/15 minutes?
Thanks
The problem has just returned
It's been working perfectly for over a month - no problems at all, not felt any slow starts or anything. And then yesterday it was totally dead. The doors opened with the fob, but that was it. Nothing at all. Wouldn't even shut without using the key manually.
I'd blown my multimeter recently so I couldn't test it, but got another last night.
I've just been to test it. The voltage was 3.5 or so.
So I used my Hummer jump start pack and it started ok, and went for a drive. I have to go somewhere soon so I couldn't do a long drive, but I needed to pop to a local shop so I drove for maybe 15 minutes and stopped (the shop isn't that far, I went a long way).
I popped in to the shop (5 minutes) and returned. Before I started the car (but after opening it with the fob), I tested the voltage and it was about 12.48?
How could it possibly go from 3.5 to 12.5 with a 10 or 15 minutes drive?
I drove home, another 5 minutes or so, and got out and checked it again. It was about 12.56. The inside lights were still on so I shut the doors, and locked them. All the lights went out.
I stood there for 15 minutes and watched as the voltage slowly dropped to 12.38.
Any thoughts please? How could it be fine for a month and then stop? How could it go from 3.5 to 12.5v in 10/15 minutes?
Thanks
Last edited by pcjn; 05-27-2018 at 08:55 AM.
05-02-2019 | 12:19 PM
#24
3rd Gear
Joined: Apr 2019
Posts: 3
Likes: 0
Battery Drain
My 04 Cayenne S is currently suffering from a 0.4 amp battery drain which I have tracked to the OEM Porsche Becker CDR 230 Model 6627 radio which has integral amplifier and a separate CD player in trunk. Only way I can stop this drain on battery is to remove the fuse in RH Fuse panel. This drain is there when radio switched off and 'asleep'. No PCM fitted of course.
I am not sure if its the radio or CD at fault or somewhere else in the wiring. There are just 3 wires to back of radio power section ie Red/Yellow permanent 12+ feed, Brow - Negative and white which I think is power to CD player. Thia model does have the fibre optic feed between head unit and CD player.
I have seen several mentions of this problem but not a lasting cure.
Should I just junk the Becker unit and buy an after market up to date radio with BT etc ?
I am not sure if its the radio or CD at fault or somewhere else in the wiring. There are just 3 wires to back of radio power section ie Red/Yellow permanent 12+ feed, Brow - Negative and white which I think is power to CD player. Thia model does have the fibre optic feed between head unit and CD player.
I have seen several mentions of this problem but not a lasting cure.
Should I just junk the Becker unit and buy an after market up to date radio with BT etc ?
05-02-2019 | 12:38 PM
#25
Instructor
Joined: Jun 2016
Posts: 207
Likes: 1
From: Portland, Ontario
My 04 Cayenne S is currently suffering from a 0.4 amp battery drain which I have tracked to the OEM Porsche Becker CDR 230 Model 6627 radio which has integral amplifier and a separate CD player in trunk. Only way I can stop this drain on battery is to remove the fuse in RH Fuse panel. This drain is there when radio switched off and 'asleep'. No PCM fitted of course.
I am not sure if its the radio or CD at fault or somewhere else in the wiring. There are just 3 wires to back of radio power section ie Red/Yellow permanent 12+ feed, Brow - Negative and white which I think is power to CD player. Thia model does have the fibre optic feed between head unit and CD player.
I have seen several mentions of this problem but not a lasting cure.
Should I just junk the Becker unit and buy an after market up to date radio with BT etc ?
I am not sure if its the radio or CD at fault or somewhere else in the wiring. There are just 3 wires to back of radio power section ie Red/Yellow permanent 12+ feed, Brow - Negative and white which I think is power to CD player. Thia model does have the fibre optic feed between head unit and CD player.
I have seen several mentions of this problem but not a lasting cure.
Should I just junk the Becker unit and buy an after market up to date radio with BT etc ?
05-12-2019 | 09:24 AM
#27
Pro
Joined: Jun 2017
Posts: 516
Likes: 79
From: UK
Hi all,
The problem has just returned
It's been working perfectly for over a month - no problems at all, not felt any slow starts or anything. And then yesterday it was totally dead. The doors opened with the fob, but that was it. Nothing at all. Wouldn't even shut without using the key manually.
I'd blown my multimeter recently so I couldn't test it, but got another last night.
I've just been to test it. The voltage was 3.5 or so.
So I used my Hummer jump start pack and it started ok, and went for a drive. I have to go somewhere soon so I couldn't do a long drive, but I needed to pop to a local shop so I drove for maybe 15 minutes and stopped (the shop isn't that far, I went a long way).
I popped in to the shop (5 minutes) and returned. Before I started the car (but after opening it with the fob), I tested the voltage and it was about 12.48?
How could it possibly go from 3.5 to 12.5 with a 10 or 15 minutes drive?
I drove home, another 5 minutes or so, and got out and checked it again. It was about 12.56. The inside lights were still on so I shut the doors, and locked them. All the lights went out.
I stood there for 15 minutes and watched as the voltage slowly dropped to 12.38.
Any thoughts please? How could it be fine for a month and then stop? How could it go from 3.5 to 12.5v in 10/15 minutes?
Thanks
The problem has just returned
It's been working perfectly for over a month - no problems at all, not felt any slow starts or anything. And then yesterday it was totally dead. The doors opened with the fob, but that was it. Nothing at all. Wouldn't even shut without using the key manually.
I'd blown my multimeter recently so I couldn't test it, but got another last night.
I've just been to test it. The voltage was 3.5 or so.
So I used my Hummer jump start pack and it started ok, and went for a drive. I have to go somewhere soon so I couldn't do a long drive, but I needed to pop to a local shop so I drove for maybe 15 minutes and stopped (the shop isn't that far, I went a long way).
I popped in to the shop (5 minutes) and returned. Before I started the car (but after opening it with the fob), I tested the voltage and it was about 12.48?
How could it possibly go from 3.5 to 12.5 with a 10 or 15 minutes drive?
I drove home, another 5 minutes or so, and got out and checked it again. It was about 12.56. The inside lights were still on so I shut the doors, and locked them. All the lights went out.
I stood there for 15 minutes and watched as the voltage slowly dropped to 12.38.
Any thoughts please? How could it be fine for a month and then stop? How could it go from 3.5 to 12.5v in 10/15 minutes?
Thanks