My new-to-me 996TT arrived yesterday, after shipment across the country, and let's just say we have a little research, learning, and fixing ahead of us. ;-)
I took it out for a road test, and though it drove well around town, experienced the following when I hit the highway and opened it up a bit:
- The engine gave off an interesting sound which occurs only when mashing the pedal hard. I don’t remember hearing this sound when I accelerated the vehicle the day of purchase when I first drove it at the end of Feb, and did a PPI (including road test) with a local indy. Granted neither the mechanic nor I drove it that fast on open roads that day. The sound is like either sheet metal fibrillating, or possibly (guessing here) a waste gate dumping? It made me wonder if the heat shield(s) diagnosed as loose during the PPI, and repaired by PPI indy prior to shipment, were still loose.
- The max boost I could produce on the highway at speeds (as displayed on the dash readout) while driving in the 60-110 mph range was 0.4 (rarely) or 0.3 (most of the time) when I felt safe pushing the throttle hard for several seconds.
- Coming off the highway decelerating somewhat hard from 110mph down to maybe 70mph I got a couple beeps and the alternating “PSM / ABS failure”, “drive to shop” messages flashing on the dash.
- A mile or so later, I got a separate CEL and “drive to shop” msg.
The car is 2001, all stock, and generally the PPI was clean. I put my Durametric on it, and cruised through all the screens, looking for fault codes, and key engine metrics. I found the following throughout the system:
- Engine:
- P0103 / Porsche fault code 115 – Hot film MAF sensor
- P1671 / Porsche fault code 407 – DME relay Porsche fault code
- P1601 / Porsche fault code 660 – CAN timeout – instrument cluster
- P1249 / Porsche fault code 231 – Boost pressure deviation Below limit
- P1101 / Porsche fault code 594 – Input variables charge measurement
- Air Bag: Fault code 3 – supply voltage
- Litronic Headlights HBA:
- Fault code 1 – Engine path left
- Fault code 2 – Engine path right
- Fault code 3 – Axle-position sensor front
- ABS/PSM 5.7: Fault Code 5525 – Incorrect data transfer with DME master control unit.
Good news is cam deviations were quite low, and misfires zero.
The shipper mentioned the battery died during shipment (after-market radio left on was his first theory). He had to jump the battery when it came time to shuffle the load on his rig. Could any of the above codes be triggered by a battery drain event? I'm not averse to clearing codes and test driving further to see if they return, but didn't want to destroy any clues too soon by clearing codes.
A couple other minor clues or facts to share in context of the above:
- Seller kept the car on a battery tender, perhaps indicative of the after-market radio (installed at car purchase in 2001) being wired (per shipper's theory) in such a way that it isn't ignition-switched in its power supply?
- During PPI there was evidence of rodents (seeds, etc.) in the area in front of the dash, driver's side, as seen through the plastic grill with frunk open. I am wondering if "P1601 CAN timeout - Instrument cluster" might be related to any rodent damage to wiring. All systems seem to function normally in the cockpit.
- During PPI the front right headlight wasn't working (witnessed by the mechanic and by me). A few weeks later, when I had same shop do some work on the car while waiting for shipment, the other mechanic said both headlights were working, nothing to repair. Interesting. What can cause a headlight to be intermittent in operation?
- Front right outer CV boot was torn, and some early sign of corrosion on the axle, so I agreed to have shop replace it. Could "Litronic fault code 3 Axle-position sensor front" be related to that?
- Other work performed by local indy prior to shipment included new spark plugs and coils, oil and filter change, right motor mount replacement (PO's shop had replaced left mount only), new drive belt, rear brakes (rotors, pads, sensors) and brake fluid flush.
Full detail on the car is
here on BaT, if anything there is helpful. I can also post a bunch of Durametric screen grabs, or log a session if that is helpful.
I appreciate any advice from the experts here. I researched a number of these fault codes on rennlist last night, as well as phrases "PSM/ABS" "weak boost", etc. and understand the PSM/ABS failures can be triggered by a number of root causes. I'm also interested in learning more about DIY methods for reasonably competent owners diagnosing boost system issues (loose hoses, failed or oily MAFS, etc.). Yes, search is our friend. But so are the black belts here. Thanks in advance.
https://cimg9.ibsrv.net/gimg/rennlis...92b8e9d9e5.jpg
PS: it has the dreaded sunroof rattle, but that's a topic for another day. Plenty of threads out there already on that matter.