Mark Hubley

Within a few miles of home, after a 400 mile trip to Worcester, MA, my '99 Boxster threw a CEL at me. After getting home I checked it with my Durametric, which told me P1531, Camshaft Adjustment Bank 1 (that was the only code). I reset, then took a 20 minute drive, no light. Drove the car to work this morning, and CEL is back on. Don't have the code reader with me, but I'll guess it's the same code. Engine seems to be running perfectly fine.

I've done a search, and come up with some mixed info about whether this means the Variocam actuator is bad, or if it's just a bad sensor. However, those posts were from a few years back.

Anybody have any recommendations?

Of course, I'll check the code when I get home. If it's the same P1531, no other codes, and the car seems to be running fine, does that point to a bad sensor or a bad connection somewhere?

Cheers,

Mark

Chuck W.

I Goggled "Porsche P1531". Lots of info but no different answers. Could be a couple things. Good luck and keep us posted.

Macster

Went through this a while back with my 02 Boxster. Passenger side.

Turned out to be a bad VarioCam solenoid and actuator. My info is if the tech has to open the engine up (the engine does *not* have to come out of the car) to get to the VarioCam solenoid you might as well bite the bullet and pay the extra mone to have the actuator replaced. More labor (a few more hours because the cams have to come out and of course have to go back in and be timed) and more parts cost. Neither the solenoid or the actuator are inexpensive. Roughly $700 to $800, each.

But along with the error code was the symptom of the engine running really rough, rpms going up and down with the rpms falling so low on the down side I thought the engine was going to stall/die even with the tranny in neutral and the clutch out.

As soon as I gave the engine some throttle though the engine smoothed right up though and remained smooth up to around 4K. I didn't want to rev the engine up any more than that.

I cleared the error code and drove the car some (30+ miles home) but the check engine light came back on. Can't recall if the engine symptoms returned.

In your car's case though it might not be a solenoid. There's a triggering wire short to ground possibility or the positive supply to the actuator is bad or the triggering wire has a break in it.

You need to eliminate the above possibilities or have a tech eliminate them before you spring for a solenoid/actuator R&R.

Sincerely,

Macster.

Mark Hubley

Thanks for the replies!

Macster (or anyone else who cares to chime in), would you take this to a dealer or an independent shop? I generally favor the indies, but I wonder how much experience an indy would have with this type of problem. Maybe this is something that neither a dealer nor an indy would have much (or any) experience with.

I'm reasonably handy in the garage: I do all the maintenance on my Boxster (but with 44K miles, it's all been routine), I've replaced timing belts on my 924S and replaced the clutch on a 944, etc. However, I'm not sure where to start with something like this.

Along the lines of Macster's post, it would be nice if I could just find the wire in question and see if the connections are good.

Macster

The job is tricky.

Almost certainly one (or more) exhaust fasteners will break/snap off and need attention. One of the 3 that fastens the exhaust system to the header/pre-cat snapped on my car and required extra time to deal with. (Because I have my cars serviced/worked on at this dealer regularly the service department didn't charge me the extra labor cost.)

The camshaft bolts must be replaced. They should not be reused. The concern is not that they are stretch bolts (at least I don't think they are) but that they are micro-encapsulated and this helps prevent oil leaks from the camshaft cover bolt holes.

The camshaft cover holds the cams in place and makes up the upper half of the camshaft bearings. The bolts in the center of the cover are on either side of the camshaft bearings and as a result are very near high pressure oil. Sure, the assembly calls for a bead of special sealant -- which was ordered from Porsche -- around the bolt holes but the micro-encapsulated bolts are a second defense against oil leaks.

Next the techs tell me that their experience is often enough both the VarioCam solenoid and actuator are bad and even though the solenoid is bad both the solenoid and the actuator should be replaced 'while one is there'.

Sure this sounds like invoice padding but the good sense of this was hammered into me by what happened with my car.

Briefly as I can make it, I took the car to the dealer and the tech id'd the solenoid was bad. I gave permission to replace the solenoid. At the same time I was not asked about the actuator, it was not mentioned to me.

After I got the car back after just 30 or so miles of driving the symptoms were back. I took the car back and the tech investigated and found the new solenoid was ok (rarely but it happens that one is bad out of the box) and the diagnosis was that the actuator was bad and it would need to be replaced.

I was taken quite by surprise by this and was feeling rather sick not so much because of what I was expecting the duplicate work would cost me but that I would no longer be able to take my cars to this dealership and would either have to find another dealer to rely upon -- there are several in my area but none are as conventently located to me -- or sell my Porsches and move to another brand of car.

Before I could even begin to formulate a response to this the service manager told me that the extra labor/parts this required would be covered by the dealer. I would have to pay for the new actuator and the extra labor (about 4 hours) that is required to go beyond the solenoid (the cams have to come out and then be put back in and retimed) but the parts/supplies/labor to get to the solenoid I would not be charged for. The dealer service department would absorb this cost.

For some reason I was not given the choice of having the actuator changed at the same time the solenoid was replaced with the explanation that often enough both prove to be bad when only one can be confirmed bad.

(Might add I have both old parts and have looked at them closely and can see no signs of any distress. Even the acuator guide pads show little signs of wear with over 240K miles of use. Both items are sealed/non-servicable items too.)

Anyhow, had I been given this choice, I would have granted permission to replace the actuator at the same time as the solenoid. The service manager knows me well enough that I would have relied upon the techs' and their recommendation. My belief is that I either trust the techs or I find a place where I trust the techs or I get rid of the cars.

In this case I would have trusted them and had both the solenoid and the actuator replaced. The techs tell me that their experience is that the solenoid masks a bad actuator.

The problem is that one can't tell the actuator is bad until the new solenoid is in place and of course the engine is buttoned up. However, by this time then one is looking a duplicate of the labor, parts (save the solenid which can be reused) and supplies to go back into the engine and replace the actuator.

So, the techs tell me their SOP is to replace both.

Now to your question: indy or dealer. You can take the above and run some of or all it by your indy and see how he responds. If he dismisses the need to replace the bolts, if he shortsells the odds a bolt will snap, if he tells you the actuator never goes bad or in some way tells you something that disagrees with the above, my experience, maybe you want to consider a dealership.

Or not. It comes down to I guess you either trust the indy or you do not.

Tackle this job yourself?

Well, as I started with above it is a tricky job. If you can find a DIY that covers this though, that might help.

The cams have to come out and this requires some knowledge of how to do this right so something bad doesn't happen that can have you looking at dropping the engine so you can disassemble it to address the extra trouble you caused yourself. What this is I can only imagine having never been inside of one of these engines. But for instance if a camshaft to IMS chain fell off a sprocket even if you could pull this chain up and l away the timing links may not be reliable and you'd have a tougher time retiming the cams; or a tensioner came loose and you'd have to tear apart the engine to reposition this tensioner.

I've been inside various other engines but I'd be leery of tackling this job. I do not have the in-depth knowledge of how these engines are put together to know the proper disassembly/reassembly procedure to avoid the various pitfalls that I'm sure lurk in a job like this.

However, you are not at the replace the solenoid/actuator decision yet. My advice would be to either confirm the solenoid is bad or not and if not what is wrong (as I covered -- though not in detail -- in an earlier post there can be a wiring/power supply problem).

If you are up to this fine. If not then you need to take the car to a place that can do this for you. If you have to take the car to a place to have the real problem id'd you are almost certainly not up to the solenoid/actuator R&R job. No shame in that. The techs I talk to have been doing this for years and have received uncounted hours of training on these engines. Believe it or not I asked about this training, could I sign up for some (at my own expense of course) and was told the training is only open to qualified techs.

Sincerely,

Macster.

Mark Hubley

Macster--I really appreciate the detailed comment. Very helpful.

Here's my evening update: Checked the CEL, and it is still P1531. Perhaps it's my imagination, but on the ride home the sounds coming from the motor seemed a bit off. Idle seems smooth enough, but it sounded off at low RPM. For example, I stepped on the gas from 45 MPH in 4th, and it sounded odd and had very little pull. On the other hand, I don't think I've ever driven this car at 45 in 4th before, so who knows.

At this time I'm thinking I'll bring the car to my local dealer.

Macster

I hope my replies are of some value.

Also, sorry about the length but some of these subjects are rather complex and I like to give you my thinking to help you have as much info as possible so you can make a better decision as to what's right for you and your situation.

What you feel vis a vis the engine and its performance may be normal given the situation.

The DME will want to activate VarioCam at low rpms. Roughly I think it wants to kick in at around 1400 rpms. Thus then what you may have been feeling when operating the engine in 4th gear at lower speeds is how the engine feels sans a fully functioning VarioCam system.

During my driving of my car after the first CEL I tried to avoid to operating the engine at too low of rpms in too high a gear to avoid triggering the VarioCam. Also, I avoided high rpm operations for the same reason. At a bit over 5K rpms the VarioCam is once again activated. So I kept rpms above 2K except on 1st gear and below 4K in all gears.

Do not sell VarioCam short. It is a very important conttributor to these engines and their overall performance. And I'm not just referring to the their peak hp or torque numbers either.

Also, the engine mixture may be off. When my car's engine's VarioCam started acting up what I observed is the DME was enrichening the passenger side bank in an attempt to adapt to the out of the acceptable range O2 sensor readings due to the lack of a proper functioning VarioCam on that bank.

Speak to your local dealer. That is speak with the SM and the senior techs. I think given the situation and the size of the repair bill -- should you elect to have the work done there -- you are entitled to ask some questions, express your concerns, to make a determination as to what you want to do.

You can't expect to receive a full engine rebuilding class but ask about teh bolts. The reuse of the camshaft cover bolts. Their experience with bad solenoids masking bad actuators and so on.

Their experience might be different.

Also, and maybe I should have put this ahead of the above, but in a diplomatic manner/fashion ask about what can be done to pinpoint the cause of the problem *before* the engine is torn into. What about confirming the solenoid's ok (or not) and the wiring/connector are ok (or not) before just throwing expensive solenoid and actuators at the symptoms.

Sincerely,

Macster.

racer

On my '00 2.7 I suuffered a failed variocam actuator too. Back then, iirc, part was around $800 and the total bill (worked at by IMA) came to around $2,200 iirc. Can't recall if specialized (ie, "shop") tools are required.

as a precursor to IMA, I took the car to a local Curry's shop which was able to diagnose the problem but addmitted it was beyond their technical expertise to try and do it themselves.

x2 with macster, the motor doesn't need to come out, but you DO have to trust someone to set the timing correctly (or wow.. 24 smashed valves and pistons )

My recollection of issues was 1) a CEL light and 2) difficulty with low speed idle. It then grew more difficult to drive, obviously. The first shop reset the CEL and it was fine for about 5 miles, then tripped again, so they dug deeper (see above Curry reference).

Going to a shop with a Porsche / Bosh Hammer tool will also likely provide more precise incilantion of what is wrong than a more generic scanner may provide.

Landseer

My neighbor had most of these symptoms on an 01 that was dropped at his shop.
Mystery. No check engine light. (snipped by the last owner)
Didn't have hammer, but did a lot of wire metering.
Inspected inside the DME and saw a little scorch inside the aluminum case.
Turned out to be a scorched output transistor I think on a side edge of the board.

And this part I love, the owner instructed it be put together so he could cut losses and unload it as-is.

Mark Hubley

Macster--I'm a teacher by profession, so I'm all about learning. In fact, getting and giving information is largely what Rennlist is all about, right? (In addition to general comraderie, etc.)

So, God bless you and those willing to take the time to write informative posts!

Mark Hubley

Got a call from Porsche of Annapolis yesterday. They checked the wiring, etc. and diagnosed a bad solenoid/actuator. They will be replacing both for ~$2,300. I'll update after I get the car back.

mcmike27

Our 98 986 had the exact ssame fault last Nov...the dealer wanted close to 3k fo the work our local indie did the cam act/sol and did the front engine mount (ours was shot after 12 yrs) for under $2500.00. He also checked the cam timing to make sure the IMS wasnt wobbling. All good!.... Ours also ran great just a bit of idle bumbles when is was warming up from 900 rpm to about 700 rpm once the temp comes up it's rock sild and now after the fix it runs great. They also replaced the cam actuator ramps and guides they were a bit worn (95k miles). Keep your ears and eyes open if one side did it the other side often follows suit. Ours hasnt to date but the indie says most likely it will at some point. No panic just keep an eye on things. Our indie is in York Pa Translog Porsche Tony Miller...great service...good labor rates...they only charge labor based on how many hours they worked on the issue not by the dumb *** Porsche shop manual time est.

m2

Mark Hubley

Got the car back from Porsche of Annapolis. They ended up charging ~$2,300 for replacement of one variocam actuator/solenoid. They also diagnosed a problem with the ECU, and they billed me an additional ~$1,200 for that repair.

Car seems to be running fine at this time.

The ups and downs of Porsche ownership!

logray

+1 to the DME/ECU also being a potential cause for this fault. I had the exact same issue on my 996 and it ended up being the DME that was causing the P1531 (and this was after I had already replaced the solenoid). The early ME5.2.2 DME's are known to fry the solenoids.

I have a THIRD new solenoid as well as new actuator to put in bank 1 once I start tearing into the engine again this winter for a 3.4L -> 3.6L rebore.

Macster

P1531 is the same error code my 02 produced when the passenger side VarioCam solenoid/actuator went bad.

However, I note that in my car's case the engine was obviously sick, running rough though eventually the engine's behavior improved and it appeared to run ok.

So, in your car's case, I'm less inclined to believe the solenoid or actuator is at fault. I'd at least think about eliminating the connector and doing other checks to ensure the wiring or power or signal wires are ok before considering the solenoid/actuator is bad. In fact a qualified shop with PST2/PIWIS should be able to run some tests to pretty much identify the real cause of the check engine light and its error code.

I note others have reported a DME problem... I'd be very very reluctant to delve into this possibility without first eliminating other possibilities. Mess up a good DME and you're looking at big bucks. The '99 and earlier DME's IIRC cost $5K or so. Even the newer model car DME's run IIRC over $1K, way over.

Sincerely,

Macster.