Need help!

[JebLacey]

Hi Everyone... I have posted this elsewhere as well... I am drowning here...

99 Box, Tip, 63Kmiles, strong motor, major done at 52K.

Here is the deal. I started having an intermittant problem, with the transmission going to "safe" mode, and the CEL popping up. It happened in 2 consecutive drive cycles, each time, I stopped the car, and re-started... no probs for the rest of the drive. I took the car down to a local AutoZone, and had the DTC read. I only got back P0600 (Serial Port Malf... PCM trouble communicating) I have not been able to get into a Porsche shop to get the specific code, since the long weekend closed them down, plus, I am kinda stubborn.

Anyhow, yesterday, noticed that the CEL was not coming on when i turned the key, before start. Then I tried to start, and it would not fire. The starter turns and turns (lights flash between P and D), but it sounds like no fuel. I came back out a few minutes later, the CEL was back, and the engine started. Now, it only starts when it wants to, which is about one out of every 20 tries, but i have noticed that the CEL is absent on the ones where it does not start, and always comes on when it does. I dont know what that means exactly. Has anyone ever experienced this?

Lastly, I thought it was a problem with the selector switch in the trans... but if it was, wouldnt the top not go up or down either? Now i am thinking that i have no idea what is going on. The nearest dealership is 100miles, and I dont really trust local shops other than to read codes. Let me know what you think....

P.S. Not to complicate things, but it fired perfectly about 10 times in a row today while i had the door taken apart to fix a regulator that had jumped a rail. Once i got the door back together, it stopped working (i.e. No CEL at Accessory Key, no vroom vroom). Could a short in the door somewhere cause the CEL not to test, and the fuel not to flow?

[Loren]

Hi Everyone... I have posted this elsewhere as well... I am drowning here...

99 Box, Tip, 63Kmiles, strong motor, major done at 52K.

Here is the deal. I started having an intermittant problem, with the transmission going to "safe" mode, and the CEL popping up. It happened in 2 consecutive drive cycles, each time, I stopped the car, and re-started... no probs for the rest of the drive. I took the car down to a local AutoZone, and had the DTC read. I only got back P0600 (Serial Port Malf... PCM trouble communicating) I have not been able to get into a Porsche shop to get the specific code, since the long weekend closed them down, plus, I am kinda stubborn.

Anyhow, yesterday, noticed that the CEL was not coming on when i turned the key, before start. Then I tried to start, and it would not fire. The starter turns and turns (lights flash between P and D), but it sounds like no fuel. I came back out a few minutes later, the CEL was back, and the engine started. Now, it only starts when it wants to, which is about one out of every 20 tries, but i have noticed that the CEL is absent on the ones where it does not start, and always comes on when it does. I dont know what that means exactly. Has anyone ever experienced this?

Lastly, I thought it was a problem with the selector switch in the trans... but if it was, wouldnt the top not go up or down either? Now i am thinking that i have no idea what is going on. The nearest dealership is 100miles, and I dont really trust local shops other than to read codes. Let me know what you think....

P.S. Not to complicate things, but it fired perfectly about 10 times in a row today while i had the door taken apart to fix a regulator that had jumped a rail. Once i got the door back together, it stopped working (i.e. No CEL at Accessory Key, no vroom vroom). Could a short in the door somewhere cause the CEL not to test, and the fuel not to flow?

P0600 CAN Timeout - Signal Implausible

The CAN bus is a data transmission system specially developed for use in the vehicle. The CAN bus is bidirectional, i.e. each ECM connected to it can both send and receive. The CAN bus consists of a twisted two-core wire. In your model year car only the DME control module and Tiptronic control module are connected to it.

A CAN timeout means that the DME control module was unable to establish a connection with the Tiptronic control module.

Possible causes are:

Open circuit - Wiring harness

Short circuit to ground - Tiptronic control module not plugged in

Short circuit to B+ - Tiptronic control module faulty

Short circuit

Check CAN bus from DME control module to Tiptronic control module for continuity.

1. Remove DME control module connector.

2. Remove Tiptronic control module connector.

3. Connect ohmmeter to DME control module connector, pin 85, and Tiptronic control module connector, pin

85. Display: 0-5 ohms

4. Connect ohmmeter to DME control module connector, pin 86, and Tiptronic control module connector, pin 86. Display: 0-5 ohms

If infinite ohms is displayed, check wiring harness for chafing and pinching damage.

Check CAN bus from DME control module to Tiptronic control module for short to ground.

1. Remove DME control module connector.

2. Remove Tiptronic control module connector.

3. Connect special tool 9616 to wiring harness (DME control module connector).

4. Connect ohmmeter to special tool 9616, pin 85, and ground. Display: infinite ohms

5. Connect ohmmeter to special tool 9616, pin 86, and ground. Display: infinite ohms

If 0 - 5 ohms is displayed, check wiring for chafing and pinching damage.

Check CAN bus from DME control module to Tiptronic control module for short to B+.

1. Remove DME control module connector.

2. Remove Tiptronic control module connector.

3. Connect special tool 9616 to wiring harness (DME control module connector).

4. Connect voltmeter to special tool 9616, pin 85, and ground.

Switch on the ignition. Display: 0 V

5. Connect voltmeter to special tool 9616, pin 86, and ground.

Switch on the ignition. Display: 0 V

If battery voltage is displayed, check wiring harness for chafing and pinching damage.

Check CAN bus from DME control module to Tiptronic control module for short circuit.

1. Remove DME control module connector.

2. Remove Tiptronic control module connector.

3. Connect special tool 9616 to wiring harness (DME control module connector).

4. Connect ohmmeter to special tool 9616, pins 85 and 86.

Display: = infinite ohms if 0 - 5 ohms is displayed, check wiring harness for chafing and pinching damage.

[JebLacey]

Big time thanks...

A few more q's...

Where shouldl i find the CAN bus (phys. loc), and which box is the DME and the Tip control...

Would a fault in any of these systems cause me not to have a CEL test at Accessory Key and no start on an intermittant basis?

Or is this more than one problem?

Much thanks... off to work I go.

[Loren]

Both controllers should be in the rear trunk.

If that is your only code then you likely have two problems.

I've never heard of a CAN bus problem causing a no start condition - IMHO that is more likely a bad ignition switch. Lot's of posts here about those and the intermittent/sporadic problems they cause.

[JebLacey]

Sorry to ask so many, but can I remove the connectors without removing the units from their mount? I have had a little difficulty here.

Also, if the ig. switch is failing, would i still get all my other test lights at startup? I would think it would be an all or none kind of thing, since all of the modules that have test lights are run off the DME... including the CEL.

Once again... please accept my apologies for posting so many q's.

[Loren]

I think you can get to the connectors without removing the controllers.

If the CEL was on (for the P0600 fault) then it should light at ignition "on".

Maybe just another reason to check the DME connections.

[JebLacey]

The DME is the one on the left, labled Cartronics... ?

Checking it now... it wont hurt to remove it if i need to, right? I cant seem to figure out the connection.

[Loren]

As I recall the DME is on the left and the Tiptronic is on the right.

If you want to be safe disconnect the battery.

[JebLacey]

UPDATE...

Well, big thanks to Loren for all the help. Still no luck though. I am taking the car to DMC in Destin Fl. If anyone has any experience with them, input would be appreciated.

It hasnt started in two days now, so the problem is no longer intermittant. The CEL does not test when i turn the key to accessory, and the fuel pump does not appear to be kicking in, so I know there is no fuel. I was gonna use a timing light to see if I was getting any spark, but the cable was too short to reach from the batt. to the engine compartment. Talk about pouring when it rains. I took a check light to the fuel relay... nothing. Also took it to the DME relay... nothing. I am thinking it is probably ignition switch now, as i have been previously advised, but would that explain the "no CEL test", and the fact that if i get a CEL test, I get a start? Just doesnt make any sense to me...

Anyhow, I will keep you all posted as to what they say at DMC...

[JebLacey]

UPDATE:

Took the car in 2 days ago. I told the shop that all i wanted done was the codes read, then for them to contact me. I finally got ahold of them this morning, essentially saying WTF about 2+ days to read codes. They said that the car began starting fine yesterday, and has started fine today as well. NO CODES were found...?

So now they are trouble shooting the ignition (upon my request, their concurrance). Does anyone out there have any input? If I am getting no codes whatsoever, does this make sense? Or is my shop screwing the pooch here? I have no clue at this point.

Also, does the PST2 produce a readout? Should I ask to see it? What should I look for to insure that they are actually using correct equipment? I only ask becuase they are traditionally a BMW/Jag/Benz shop. There are no Porsche specific mechs in this area that i can find/get ahold of. These guys swore that they had a Porsche guy... but I find it hard to believe (considering the ODBII code that i got two weeks ago) that there is nothing on the DME.

[Loren]

NO CODES were found...?

That is not uncommon at all. The DME will log events that are pending codes as well as triggering codes. Either can be cleared if the condition that caused the code is corrected. This is done in a certain number of drive cycles depending on the code. That is why a loose gas cap CEL will eventually clear itself (assuming you tighten the gas cap).

Also, does the PST2 produce a readout? Should I ask to see it? What should I look for to insure that they are actually using correct equipment?

Yes, the PST2 can record screen data and readings. The tech has to push a "save" button on each screen they want to record in the PST2 log. Then they have to print the log. In some cases (specifically warranty work that is requesting reimbursement) Porsche requires the log be sent in.

Here is an (very short) example log:

PST2_log.pdf

[JebLacey]

Thanks so much for all the help Loren...

Is there a religion that worships you, cause if there is, I am totally there.

On a serious note, this is such a great forum. Nobody is rude, everyone is helpful and polite, nobody makes fun of dumb questions!

I have been a member of quite a few forums in my day, but this one is the best yet.

Thanks again for all the help... I will keep you posted, and let you know what goes wrong next!

Brian

[JebLacey]

UPDATE:

The shop says the ignition is OK... now saying that it is the Tip Controller. I am wondering... does it have to be programed with a PST2, or can I put one in myself? Also, what is a good price, and what will the dealer charge, if anyone out there knows.

Does a Tip Controller Malf. sound like an answer to my problems?

[JebLacey]

Ok... so I know i have to have the Tip Control Module put in by someone with a PST2, so that it can be programed. Porsche had 2 part numbers for this part... split on VIN. Does anyone know why they changed, halfway through MY99? Mine is the later one, apparently.

Anyhow, the place that I took it to did not impress me at all...

They never returned my calls, wont explain why they are sure it is the TCM that is bad. Worst off, they told me that they found the part at Dean McCrary Porsche for $2600. I called DM, and they sell it for $1700.

Long story short, found it at Sunset for $1200. Gonna order it this week, should be here (from Germany) in 4-12 days. I will let you all know if it solves the problem.

Last thing... before I replace this computer, can anyone think of anything else I should check? New mech. recieves car monday, and I want to give him some direction.

[Loren]

On the early Tiptronic's I think the only thing you program (with a PST2) is the country code.

Where are you located?

[JebLacey]

Im in Florida (US)

Loren...

You said earlier something about the CANBUS not causing a no-start condition? What about a faulty trans control module. One thing that i have yet to desern? Does the conv. top get its gear info from the same pool as everything else? What i mean is, the mech seems to think I have a faulty trans control module, and it is not correctly telling the DME what gear it is in at start. If this is the case though, would the top still go up and down? Wouldnt the top functioning signify that the car knows its in P or N?

Maybe I am overthinking this one... or maybe i am about to replace a perfectly good Tip control module.

More to come, any imput appreciated!

[Loren]

You said earlier something about the CANBUS not causing a no-start condition?

I think I said the opposite - I doubt the P0600 and the starting problem are related. If you lose Tip to DME communication the the system goes into a "reduced driving program". The starting problem could be a bad clutch interlock switch or bad ignition switch. I could be wrong but I doubt the two problems are related.

I think it might be worth your while to find a (good) shop with a PST2 (or PIWIS) tester and find out more about the problem before you buy $1000 plus parts. You might get lucky with the Tip controller but it could be a bad connection too.

[JebLacey]

The problem is that there are not any around here. I have discovered that there are only 2 PST 2 testers within 100 miles of my location.

Gets worse... got the car today, went to clear my bill, and the sheet said faulty DME. I asked, and the guy said that there was some confusion, and it was actually my DME that was found to be faulty. He didnt know the specific codes. Either way, I am about to eat a hole in my wallet for a new one at sunset.

I know that i need a PST2 to put in the new DME, but where do i get the new immobilizer code? Will it come with the DME (assuming i ask for it)?

He checked the ignition, all the relays, and says they are all cherry...

I am lost...

BTW... what is the clutch interlock switch? I cant find it on my

The problem is that there are not any around here. I have discovered that there are only 2 PST 2 testers within 100 miles of my location.

Gets worse... got the car today, went to clear my bill, and the sheet said faulty DME. I asked, and the guy said that there was some confusion, and it was actually my DME that was found to be faulty. He didnt know the specific codes. Either way, I am about to eat a hole in my wallet for a new one at sunset.

I know that i need a PST2 to put in the new DME, but where do i get the new immobilizer code? Will it come with the DME (assuming i ask for it)?

He checked the ignition, all the relays, and says they are all cherry...

I am lost...

BTW... what is the clutch interlock switch? I cant find it on my ALLDATA subscription...?

[JebLacey]

Another UPDATE>>>

So I brought the car home, and have been trying to get it into another shop. The batt. was dead, so I charged it last night. Went out to it this morning, and turned the key. No CEL, so I didnt bother starting it. All of the sudden, about 10 seconds after i had turned the key to acc., the CEL lit up! I turned to "start", and the car fired up like it was no thing at all. The CEL stayed on, and the transmission was in the "SAFE" mode, but the engine was running! I turned it off, waited a sec, and then turned it back on! Got a CEL, and the motor started again! This time, the CEL went out after a few seconds... no error! I felt gutsy, so i drove it around the block... great! Then i took it out on the main road, went a mile or two, ran it up to about 70 mph, and returned home. Got to the house, and shut it off. It started again 10 min later when I tried again!

Had to leave, so when i came back after an hour or so, I fired it up again. Left it running in Park for about 1 min., then, as I was watching the dash lights (the CEL had not turned off after the test this time) the CEL dissappeared and the engine immediately died. I mean, it was within one second. The CEL is not testing again, and the engine is not starting! This car is torturing me!

Any advice (Loren or anyone else)?

[0586slb]

Also, if the ig. switch is failing, would i still get all my other test lights at startup?

Yes, you could still get other lights.

I would think it would be an all or none kind of thing, since all of the modules that have test lights are run off the DME...

No, they're not.

The ignition switch has 4 contacts:

The S contact - Active when key is in ignition.

The X contact - Active when in engine run position only (for load reduction when starting).

The 15 contact - Active in engine run and start position.

The 50 contact - Active in start position only (to erm, turn the starter motor).

When the ignition switch goes bad, all sorts of different combinations can occur.