The Forever CEL

[vza]

99 Boxster Base...After new Bank 2 solenoid/MAF/AOS/Battery/Plugs/Actuator Ramps both banks,I'm right where I started CEL P1539 and some misfire codes here and there...Brought  to indie....said bent valves/actuator or timing....bailed on me....car is now at another indie. Any thoughts....car actually runs and sounds well with a little lacking in pickup. Any thoughts??

[JFP in PA]

P1539 indicates "no active position" on the VarioCam system on bank 2; often an "open circuit" problem (wiring).

[vza]

Hmm....so start tracing??

[Ahsai]

The code is complaining that despite DME activating the variocam solenoid in bank2, the expected change in timing is not detected by the bank 2 cam sensor.

 

There are many things to check but at a high level the troubleshooting involves checking the following (in this order approximately):

- Use Durametric to try to activate the solenoid and see if the engine sounds different (it should). Can compare with bank 1. If no difference, it means the variocam is not actuated correctly

- Check if the solenoid gets the 12v and ground (can use Durametric to activate it and replace the solenoid by a small 5w 12v bulb)

-> If no power, it could be the wiring or the power transistor inside the DME

- Check the Solenoid resistance (could be a bad solenoid)

- Remove the solenoid. Apply 9v power and see if the pin comes out 1/8" or so

- If none of the above, it's likely the variocam actuator. If the engine has been rebuilt and always had this fault, it could be wrong installation of the plunger or missing green o-ring.

 

The above assumes the engine timing is fine (e.g. it's been running fine and the problem just popped up, as opposed to the engine just been rebuilt)

[Ahsai]

Ah, now I see you've already replaced the solenoid and actuator, my guess would be wiring or bad power transistor in the DME. Both can be verified in the steps above.

[vza]

I actually just replaced the solenoid ....not the actuator. Brought it to indie said the actuator is getting power but NOT activating or moving. So I will assume its the actuator??

Edited March 7, 2019 by vza

[vza]

Ok...so if there is power at the actuator as the indie said.... there is no doubt its a bad actuator correct? Not the dme or solenoid(solenoid was replaced already). Want to be sure before I start tearing it all down again.

[Ahsai]

 

14 hours ago, vza said:

Ok...so if there is power at the actuator as the indie said.... there is no doubt its a bad actuator correct? Not the dme or solenoid(solenoid was replaced already). Want to be sure before I start tearing it all down again.

 

Need some more clarification to avoid misdiagnosis. There are two wires powering the solenoid: 12v and ground. Both have to be working in order to activate the solenoid. The 12v is hot whenever ignition is in the last position before crank (i.e. key ON engine OFF) so it's easy for a tech to check the 12v on the solenoid plug. However, the ground is controlled/supplied by the DME and it's more difficult to test. When they said there's power they could have meant just 12v supplied to the solenoid but have they actually tested the solenoid gets the ground from the DME? If the power transistor in the DME is bad, the ground will not be supplied properly. The simplest test is to remove the solenoid (but leave it plugged in), key ON engine OFF, just use Durametric to activate the solenoid. If the solenoid pin comes out 1/8" or so, you have verified all the DME, power transistor, wires, solenoid in one go.

 

Then the only thing left is the actuator assuming there are no other codes. The P1539 code requires that there are no other faults detected such as cam position sensor.

Edited March 9, 2019 by Ahsai
Correction in bold above

[vza]

Well I believe he said the solenoid was firing.....not too sure how he would know. If there is no active ground in the plug are you just going to ground on any part of the car to see 12v? How would you test the ground coming from DME inside the plug(connecter)? Would there be a visual inside the DME (burnt/char or smell?) Well I know its not the solenoid its new, just wondering about the transistor....that would be an easy fix rather than pulling the cam cover. Is it common for  these transitors to go?? V

Edited March 8, 2019 by vza

[vza]

Viewed other threads and pix of burnt components in the DME....pretty obvious. Is there any harm in unplugging the DME and taking a look see inside? Is it a transistor or resistor that's in question?

Edited March 8, 2019 by vza

[Ahsai]

38 minutes ago, vza said:

Well I believe he said the solenoid was firing.....not too sure how he would know. If there is no active ground in the plug are you just going to ground on any part of the car to see 12v? How would you test the ground coming from DME inside the plug(connecter)? Would there be a visual inside the DME (burnt/char or smell?) Well I know its not the solenoid its new, just wondering about the transistor....that would be an easy fix rather than pulling the cam cover. Is it common for  these transitors to go?? V

Again, no way for me to know what the tech did. He could have done what you said or he could have used a 9v battery...

Also, not clear if his test included the wiring.

[Ahsai]

43 minutes ago, vza said:

Viewed other threads and pix of burnt components in the DME....pretty obvious. Is there any harm in unplugging the DME and taking a look see inside? Is it a transistor or resistor that's in question?

As long as you disconnect the battery first before removing the DME, you're fine. BTW, to test the DME is good, the easiest way is to unplug the solenoid and plug in a small 12v 5w bulb, then use Durametric to trigger variocam and the light bulb should light up. That way you don't need to remove the cam cover and solenoid. See the details in this thread where I helped another gentleman.

 

It's a bipolar transistor. Spec is here.

Edited March 9, 2019 by Ahsai

[vza]

OK Thanks....I just don't have a durametric....unfortunately!

[Ahsai]

Then it would be tough to troubleshoot. I guess you could still open up the DME and check. If there are obvious signs, you find the culprit. If there's not, then it's still not conclusive...

Durametric is something you may want to invest. I think there's another one called icarsoft, which is cheaper and MAY be able to activate the variocam as well. I'm not familiar with it though.

[vza]

OK Thanks Ahsai.....very helpful. V

[Ahsai]

I don't know if it's easy on a Boxster but if you can unplug the bank 2 solenoid then power the solenoid with a 9v battery when the engine is idling. If the solenoid and actuator both work properly, the engine note will change. If not, you will need to investigate the DME/wire side to see why the solenoid is not getting power/ground.

[vza]

Lo and behold. Well I opened up my DME and found an obvious fried Transistor, would this be the root of my problem? Hopefully!! There was another thread with the replacement part number can't seem to find it. Any help as to where to purchase the replacement transistor would be appreciated. I'll post another pic. Thanks V

 

[vza]

here's another pic.

[vza]

Bosch BIP373 Coil Driver Mod Kit from DIYAUTOTUNE is the part I need? It comes with a resistor but not too sure if I would use it. Thanks....looking forward to resolving this. V

[vza]

Numbers on the transistor 30046

                                                44313.1 any other numbers are burnt and cannot be read useless the chip next to it is the same and can be used as reference. V

[Ahsai]

Glad that was it. All the info you needed was in the thread mentioned a few posts above with pics too.

 

Yes, get the 373 and you are good to go.

[Ahsai]

https://rennlist.com/forums/996-forum/815258-variocam-actuator-trigger-voltage-2.html

 

https://rennlist.com/forums/boxster-and-boxster-s-986-forum/697289-help-with-986-ecu-repair.html

Edited March 9, 2019 by Ahsai
Added more links

[Ahsai]

You don't need the resistor from the kit. Just replace the 3 pin burnt transistor and you should be good to go.

[vza]

OK ....resistor not needed thats what I thought. ....so replace with the 373...you think that was the problem....would that allow the actuator not to engage ?? Thanks again for your input ....big help. Vince

[Ahsai]

Well, a burnt transistor likely won't be able to supply the ground properly to the solenoid so even a new solenoid won't help. Whether this is indeed the problem depends on how the tech tested everything before when he told you the solenoid got power, like I explained before. If he only testes for the 12v but never the ground side, this transistor is likely your problem.

 

However, if he indeed tested the ground side and verified the solenoid has power, then it's likely the actuator itself.