CCU problem...
02-22-2014, 01:15 PM
#16
Burning Brakes
Tore and Loren,
Regarding a replacement ccu of new design. If it was a manual versus auto temp, easier to make a replacement? Kind of like a digital version of the manual system found in a earlier 1970-1988 911?
Regarding a replacement ccu of new design. If it was a manual versus auto temp, easier to make a replacement? Kind of like a digital version of the manual system found in a earlier 1970-1988 911?
02-22-2014, 01:26 PM
#17
"If it was a manual versus auto temp, easier to make a replacement?"
Of little significance, the present CCU temp control operates as a servo control system keeping
the temp at the operator's setting. It's just doesn't have buttons to set the temp nor a digital
display to indicate the actual temp.
Of little significance, the present CCU temp control operates as a servo control system keeping
the temp at the operator's setting. It's just doesn't have buttons to set the temp nor a digital
display to indicate the actual temp.
02-22-2014, 02:06 PM
#18
Rennlist Member
Thread Starter
"As I said, the unit itself was relatively new and had just been replaced less than a year before as the original was uncovered to be non-operational in the PPI."
That doesn't sound encouraging! As has been indicated many times to Rennlist
members, the 964/993 CCU is very reliable and rarely if ever fails.
Many, including some Porsche dealers/independents assume the CCU is the source
of their 964/993 climate control problem, when in fact it's usually something
external to the CCU. Read here under 'Porsche CCU 964/993';
http://www.systemsc.com/problems.htm
Given the extent of damage indicated in the picture, most likely the main circuit
has major damage too and a problem external to the CCU is the cause.
That doesn't sound encouraging! As has been indicated many times to Rennlist
members, the 964/993 CCU is very reliable and rarely if ever fails.
Many, including some Porsche dealers/independents assume the CCU is the source
of their 964/993 climate control problem, when in fact it's usually something
external to the CCU. Read here under 'Porsche CCU 964/993';
http://www.systemsc.com/problems.htm
Given the extent of damage indicated in the picture, most likely the main circuit
has major damage too and a problem external to the CCU is the cause.
02-22-2014, 02:28 PM
#19
Rennlist Member
gmorat, you seem to have a fault in either the two SMT transistors or the resistors next to them. I do not know yet what purpose they have in the CCU.
Below is a pic of a CCU front PCB in working condition.
Cheers,
Tore
Below is a pic of a CCU front PCB in working condition.
Cheers,
Tore
02-22-2014, 11:37 PM
#20
"you seem to have a fault in either the two SMT transistors or the resistors next to them"
It can also be a circuit track that 'runs' near those devices that 'carried' too
much current.
It can also be a circuit track that 'runs' near those devices that 'carried' too
much current.
02-28-2014, 06:07 PM
#21
Rennlist Member
Thread Starter
So.......
I sent the CCU off to get fixed and 2 of the circuit boards have to replaced. The main PCB and the small unit that sits on the back of the faceplate. Anyway, they are being swapped out and the unit should be back in my possession next week some time. I have been told by the place fixing it NOT to plug it in until the source of the problem has been diagnosed and repaired. The wiring from the CCU to the blower and the blower itself need to be tested for shorts.
I'm arranging for somebody to look into all of this as soon as possible.
Who can say what the issue ends up being.
Good times! At least the weather is nice so having air whether its hot or cold isn't a major issue at the moment.
G
I sent the CCU off to get fixed and 2 of the circuit boards have to replaced. The main PCB and the small unit that sits on the back of the faceplate. Anyway, they are being swapped out and the unit should be back in my possession next week some time. I have been told by the place fixing it NOT to plug it in until the source of the problem has been diagnosed and repaired. The wiring from the CCU to the blower and the blower itself need to be tested for shorts.
I'm arranging for somebody to look into all of this as soon as possible.
Who can say what the issue ends up being.
Good times! At least the weather is nice so having air whether its hot or cold isn't a major issue at the moment.
G
02-28-2014, 08:07 PM
#22
RL Community Team
Rennlist Member
Rennlist Member
Is there something wrong with your ECU relay? My understanding was that it took the high current load off of the ECU. Fix, replace, whatever you do I would find out what load fried the thing before plugging in a replacement.
02-28-2014, 08:45 PM
#23
Rennlist Member
Thread Starter
G
02-28-2014, 11:57 PM
#24
Rennlist Member
When you get the CCU back, ask for the 2 failed circuit boards and take a close up photo of the components that fried. I can do some reverse forensics and figure out the possibilities.
03-01-2014, 12:08 AM
#25
Rennlist Member
Thread Starter
Awe.
Some.
G
03-02-2014, 03:12 PM
#26
Rennlist Member
Thread Starter
G
03-02-2014, 03:15 PM
#27
03-02-2014, 03:45 PM
#28
Rennlist Member
Thread Starter
03-02-2014, 03:50 PM
#29
Rennlist Member
I do not understand what pp000830 means by "ECU relay". There is no such thing.
The closest I get to his statement is the fact that the Climate Control Unit is controlling the front fan speed, and the high fan motor current is taken care by a "Final Stage" amplifier placed just behind the fuse box. (under the plastic covering) This module can fail, and could kill the CCU. However, I find this rather unlikely in this case.
The CCU is also controlling several relays, i'e. the oil cooler fan speed relay, condenser fan relay and so on. I also find it unlikely that one of these have killed the CCU in this case, but it is difficult to tell without having seen the CCU PCB's and any failed components. (or statement from the repair service)
Cheers,
Tore
The closest I get to his statement is the fact that the Climate Control Unit is controlling the front fan speed, and the high fan motor current is taken care by a "Final Stage" amplifier placed just behind the fuse box. (under the plastic covering) This module can fail, and could kill the CCU. However, I find this rather unlikely in this case.
The CCU is also controlling several relays, i'e. the oil cooler fan speed relay, condenser fan relay and so on. I also find it unlikely that one of these have killed the CCU in this case, but it is difficult to tell without having seen the CCU PCB's and any failed components. (or statement from the repair service)
Cheers,
Tore
Last edited by ToreB; 03-03-2014 at 02:36 AM.
03-02-2014, 06:33 PM
#30
6th Gear
Join Date: Jan 2014
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Sorry to see your CCU
It looks a bit of a mess, glad that it has been contained to the cct board and ribbon tape.
I would suggest that you have had an insulation failure of the ribbon tape on the outside of its bend, when the cct board is in its normal position.
Does the tape rub against or may have rubbed against anything when it is in its original position?
Not a nice smell, you will never forget it
I would suggest that you have had an insulation failure of the ribbon tape on the outside of its bend, when the cct board is in its normal position.
Does the tape rub against or may have rubbed against anything when it is in its original position?
Not a nice smell, you will never forget it