MY 2000 996 variocam malfunction
05-14-2015, 06:50 PM
#1
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MY 2000 996 variocam malfunction
My 2000 C2 lit its check engine light. The retrieved fault indicated a variocam problem (cam timing fault). The recommendation was to replace the Hall Sensor to isolate the problem. I replaced the sensor, but the check engine light cam back on. This is the early 3.4 model with the more basic, stepped as opposed to continuous, variocam hardware.
I presume this is the same fault, meaning that there is something mechanically wrong with the cam timing hardware.
Can someone who has been inside these engines tell me: 1. What are the likely failure modes in the variocam mechanicals? 2. I understand I will not pass an emissions test with the problem uncorrected, but what do I risk driving the car for a while in this condition? What's the worse case scenario?
This is a 2000 Carrera with 68K. I will probably do the repairs but cash flow problems at present do not allow me to do the repairs immediately (just retired, downsizing household).
I presume this is the same fault, meaning that there is something mechanically wrong with the cam timing hardware.
Can someone who has been inside these engines tell me: 1. What are the likely failure modes in the variocam mechanicals? 2. I understand I will not pass an emissions test with the problem uncorrected, but what do I risk driving the car for a while in this condition? What's the worse case scenario?
This is a 2000 Carrera with 68K. I will probably do the repairs but cash flow problems at present do not allow me to do the repairs immediately (just retired, downsizing household).
05-14-2015, 07:05 PM
#2
Rennlist Member
My 2000 C2 lit its check engine light. The retrieved fault indicated a variocam problem (cam timing fault). The recommendation was to replace the Hall Sensor to isolate the problem. I replaced the sensor, but the check engine light cam back on. This is the early 3.4 model with the more basic, stepped as opposed to continuous, variocam hardware.
I presume this is the same fault, meaning that there is something mechanically wrong with the cam timing hardware.
Can someone who has been inside these engines tell me: 1. What are the likely failure modes in the variocam mechanicals? 2. I understand I will not pass an emissions test with the problem uncorrected, but what do I risk driving the car for a while in this condition? What's the worse case scenario?
This is a 2000 Carrera with 68K. I will probably do the repairs but cash flow problems at present do not allow me to do the repairs immediately (just retired, downsizing household).
I presume this is the same fault, meaning that there is something mechanically wrong with the cam timing hardware.
Can someone who has been inside these engines tell me: 1. What are the likely failure modes in the variocam mechanicals? 2. I understand I will not pass an emissions test with the problem uncorrected, but what do I risk driving the car for a while in this condition? What's the worse case scenario?
This is a 2000 Carrera with 68K. I will probably do the repairs but cash flow problems at present do not allow me to do the repairs immediately (just retired, downsizing household).
As far as warning for driving the car, the cam chain could dislodge from the variocam & start breaking parts!
05-14-2015, 07:12 PM
#3
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Thanks prodriver - I'll call about the fault code # when the shop reopens Friday. What the service technician (Porsche dealer0 told me when asked this same question was that the engine would consume more fuel in its current condition, and would not pass the sniff test but he did not mention a cascading failure type of problem. I as wondering if he just didn't want to scare me so that's why I came to the forum for some input. I will ask the shop foreman more question tomorrow. Thanks.
05-14-2015, 09:00 PM
#4
Rennlist Member
Maybe it's just the solenoid that activates the VarioCam.
It would be good to know if the VarioCam chain wear pads have been replaced.
Cam timing deviations result from worn oe pads.
It would be good to know if the VarioCam chain wear pads have been replaced.
Cam timing deviations result from worn oe pads.
05-15-2015, 11:56 AM
#5
Race Director
My 2000 C2 lit its check engine light. The retrieved fault indicated a variocam problem (cam timing fault). The recommendation was to replace the Hall Sensor to isolate the problem. I replaced the sensor, but the check engine light cam back on. This is the early 3.4 model with the more basic, stepped as opposed to continuous, variocam hardware.
I presume this is the same fault, meaning that there is something mechanically wrong with the cam timing hardware.
Can someone who has been inside these engines tell me: 1. What are the likely failure modes in the variocam mechanicals? 2. I understand I will not pass an emissions test with the problem uncorrected, but what do I risk driving the car for a while in this condition? What's the worse case scenario?
This is a 2000 Carrera with 68K. I will probably do the repairs but cash flow problems at present do not allow me to do the repairs immediately (just retired, downsizing household).
I presume this is the same fault, meaning that there is something mechanically wrong with the cam timing hardware.
Can someone who has been inside these engines tell me: 1. What are the likely failure modes in the variocam mechanicals? 2. I understand I will not pass an emissions test with the problem uncorrected, but what do I risk driving the car for a while in this condition? What's the worse case scenario?
This is a 2000 Carrera with 68K. I will probably do the repairs but cash flow problems at present do not allow me to do the repairs immediately (just retired, downsizing household).
On the 996 engine the solenoid is not that much of a job to replace.
If so one approach would be to replace this and road test the car. If the error codes come back replace the actuator. Provided of course the codes point to these items.
I'm always reluctant to continue to drive one of these cars with an error with the cam timing present.
However, when my Boxster had what proved to be its passenger side VarioCam solenoid/actuator go bad I did drive the car 30 miles home. The "failure" occurred just as I was pulling into the office parking lot.
I read the codes then shut off the engine. Then a few minutes later upon a restart the engine symptoms were gone. The light stayed off. I took it easy on the way home and was prepared to shut off the engine first then pull off the road should the engine give any sign of trouble. It was a weekend and early in the day so traffic was rather light.
However, had the engine resuming its untoward behavior upon restart I would have had the car flat bedded to the dealer for repairs.
My advice is to err on the side of caution. Right now the engine can be fixed for not too much money. (The actuator is not a cheap part and labor to replace it can be a bit expensive, too, but cheaper than tossing the car away.) If you drive the car you risk doing further damage or the failure escalates and more serious damage results to the point the engine is toast.
Park the car until you can get the problem diagnosed and fixed.
05-15-2015, 12:07 PM
#6
Former Vendor
Actuators seldom fail. I only see one every 2-3 years.
wear pads and the solenoid are the primary culprits for this.
Get a scan tool on it, unless the deviations are a full 23-27 degrees its NOT the actuator.
wear pads and the solenoid are the primary culprits for this.
Get a scan tool on it, unless the deviations are a full 23-27 degrees its NOT the actuator.
05-15-2015, 02:53 PM
#7
Captain Obvious
Super User
Super User
Mine had a fried transistor (I think that's the proper name) in the ECM. You will need to do a complete sytematic check, starting at the actuator solenoid connector and work backwards. I didna write up last summer on my quest to fix the problem. Use the search option and look for my thread. The fix was an $8 part that only required the ECM to be openned. 
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05-16-2015, 01:55 AM
#8
Former Vendor
Mine had a fried transistor (I think that's the proper name) in the ECM. You will need to do a complete sytematic check, starting at the actuator solenoid connector and work backwards. I didna write up last summer on my quest to fix the problem. Use the search option and look for my thread. The fix was an $8 part that only required the ECM to be openned.
05-16-2015, 04:51 AM
#9
Captain Obvious
Super User
Super User
Yes but just a running a low voltage power (9v for example) to the solenoid and listenning to the idle change does the same thing too. Easier to to this than to splice into the other bank and risking blowing the "driver transistor" for the other bank too. I actually ran +12v to mine to test this.
Here is what worked for me: https://rennlist.com/forums/996-foru...r-voltage.html
Here is what worked for me: https://rennlist.com/forums/996-foru...r-voltage.html
02-19-2017, 11:32 PM
#10
Drifting
I have read dozens and dozens of posts on the subject,read articles,studied wiring diagrams and spent hours trying to positively confirm the exact fault.I have made jumper cables to fit both sides of the connector and used Durametric to help.
In one obscure sentence Jake has written the best diagnostic test.
" run a jumper wire from the other bank's harness and see if the results change..
"Actuators seldom fail. I only see one every 2-3 years.
wear pads and the solenoid are the primary culprits for this.
Get a scan tool on it, unless the deviations are a full 23-27 degrees its NOT the actuator.
Thank you Jake because the actuator is $800++
Solenoid+ Actuator can be $1000 + some very tight,difficult mechanical work
Last edited by Schnell Gelb; 02-20-2017 at 12:50 PM.
02-20-2017, 12:49 PM
#12
Drifting
I think the solenoid on Bank 1 has failed. It has failed every test I could try w/o removing the cam cover. Next step is to make a custom harness to try Jakes method as final confirmation.
It is an issue not just because of the parts cost but because of the difficult work with the engine in the car(Bxstr S!)
Mine is a newly rebuilt engine(by me). I never did figure out how to test actuators and solenoids on the rebuilt engine before installation.
Rookie ignorance with appropriate penalty ! Other than this ,the engine runs beautifully.
It is an issue not just because of the parts cost but because of the difficult work with the engine in the car(Bxstr S!)
Mine is a newly rebuilt engine(by me). I never did figure out how to test actuators and solenoids on the rebuilt engine before installation.
Rookie ignorance with appropriate penalty ! Other than this ,the engine runs beautifully.
02-20-2017, 02:00 PM
#13
Schnell, is yours a MkI? if you tried to energize the solenoid with 12v and it does not work, your problem is in the solenoid and/actuator combined unit. Have you ohmed out the solenoid? Did you use Durametric to activate them? That seems to be your problem. Jake's test is to eliminate the DME power MOSFET (transistor) problem and wiring problem on the non working bank.
Inside the DME, there is one transistor per bank independently to drive each solenoid. If your transistor failed or you have a wiring problem, your solenoid is not going to activate on that bank hence the direct power to the solenoid test...to bypass the transistor and wires.
If direct power works (not your case), you can use Jake's test to see if the good transistor and wires from the other bank can drive the solenoid.
Inside the DME, there is one transistor per bank independently to drive each solenoid. If your transistor failed or you have a wiring problem, your solenoid is not going to activate on that bank hence the direct power to the solenoid test...to bypass the transistor and wires.
If direct power works (not your case), you can use Jake's test to see if the good transistor and wires from the other bank can drive the solenoid.
02-21-2017, 01:05 PM
#15
Drifting
Schnell, is yours a MkI? if you tried to energize the solenoid with 12v and it does not work, your problem is in the solenoid and/actuator combined unit. Have you ohmed out the solenoid? Did you use Durametric to activate them? That seems to be your problem. Jake's test is to eliminate the DME power MOSFET (transistor) problem and wiring problem on the non working bank.
Inside the DME, there is one transistor per bank independently to drive each solenoid. If your transistor failed or you have a wiring problem, your solenoid is not going to activate on that bank hence the direct power to the solenoid test...to bypass the transistor and wires.
If direct power works (not your case), you can use Jake's test to see if the good transistor and wires from the other bank can drive the solenoid.
Inside the DME, there is one transistor per bank independently to drive each solenoid. If your transistor failed or you have a wiring problem, your solenoid is not going to activate on that bank hence the direct power to the solenoid test...to bypass the transistor and wires.
If direct power works (not your case), you can use Jake's test to see if the good transistor and wires from the other bank can drive the solenoid.
Thank you for your interest. I have read most of your previous posts and used your 13.5 ohm test. Both solenoids test at 13.5 ohms. But Durametric confirms bank one is not responding. Reluctantly ,I have to concede it is likely the (expensive) actuator.Fortunately I have a 10% off coupon from Pelican but...
I wrote up a how-to-diagnose article to help others. It is a w.i.p. so will add more to it when I get to the root of the problem.