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Porsche 996 Troubleshooting

Could a vacuum leak cause your Porsche 996 to run rough? Has your Porsche 996 set error codes which you need help deciphering? Sometimes a Porsche 996 problem seems more daunting than it actually is. In such cases it pays to ask an Expert for help diagnosing a problem and providing a timely and practical solution.

Read below for answers provided by Experts to Porsche 996 questions asked by owners.

How to troubleshoot a Porsche 996 which runs rough after 2000 rpm?

An air leak past the airflow meter (MAF) could cause the engine to run rough, because it sucks in air which is not detected by the ECU and hence not compensated for. Consequently the fuel mixture becomes lean leading to rough running. Since this is a mechanical fault the fault light might not come on but a leak typically generates an audible hiss when the engine runs. Check that all hose clips are tight and examine the trunking for splits and cracks. Also, check the vacuum system and small bore pipes and fittings for signs of fracture.

What is the solution when a 996 Tiptronic does not slip into park so the keys cannot be removed?

There could be a wiring or crimping problem in the connections of the brake pedal switch. Check with a multimeter that the switch is good and working well. The reason for checking the switch is because of the link between the gearbox controller and brake switch. The controller will not release the lever to shift out of park unless there is pressure on the brake pedal switch. If nothing is visibly wrong then there is no option but to fall back on an emergency solution. Look for a tiny 1.00mm hole toward the back of the bezel. Insert a small piece of stiff wire, like a straightened paper clip, into this hole and press down. This activates a little switch which should release the key.

What do codes P0300, P0306, P0304, P0305 and P0102 mean on a Porsche 996?

Code P0102 indicates a problem with the mass air flow sensor or with air being sucked into the engine which the sensor is not able to detect. The most common reason for this is a vacuum leak in the engine. Codes P0300, P0304, P0306, and P0305 all relate to engine misfire, but not necessarily the cause of misfire. Most often the misfires are fuel injector related; either the injectors are restricted or fail to atomize properly.

After turning off a 996 ignition why does a new battery voltage drop to below 12 volts?

An alternator normally charges at between 13.5 and 14.5 volts which generally remains at 12V when the ignition is turned off. If it drops below this then the charging system is probably faulty which would cause the battery/generator warning light to turn on. Check the charging system which will probably reveal a faulty alternator which is not charging.

Why has the clutch on a Porsche 996 failed at only 68,000 miles?

The clutch on a high-performance car meets far greater demands than does a clutch on a normal vehicle. 68,000 miles on one of these is good service from a clutch and fairly normal.

Why does a Porsche 996 emit grey-white smoke when started for the first time in the day and when pulling away from stops?

The crankcase pressure relief valve (PCV) could be faulty and sticking in the open position. The PCV is intended to release excess pressure intermittently, but being spring loaded sometimes sticks open allowing the engine to suck oil-laden air out of the crankcase. When this happens the engine emits a bluish smoke. Remove the air intake pipe and look inside for traces of oil. If traces are evident then the PCV needs to be replaced.

Why has a Porsche 996 engine started to stutter after the fuel tank was refilled?

Case details: The engine was left running while the tank was being filled lest it would not start again if turned off.

The engine should always be switched off when adding fuel. In this case, the purge valve could have been activated, which would create a vacuum, resulting in fuel being sucked out of the fuel tank during filling. This fuel would have found its way to the engine through the charcoal canister, which would cause the engine to sputter. It can also cause the engine to continue to run, even if the key was removed, because contact between unburned fuel and hot cylinders would have caused the fuel to ignite. Have the evaporation system checked to ensure the charcoal canister is not damaged. If either is damaged it will need to be replaced. Till this is done, and the problem resolved, it would not be advisable to run the vehicle and risk engine damage.

Like all high-performance cars, maintaining a Porsche 996 can be a challenge to a relatively non-technically inclined owner. Here is where the Expert comes in, to help unravel the complexities of this vehicle. An Expert can provide information, answers to questions and solutions to problems. An Expert’s knowledge is invaluable when up against an issue. When in doubt, ask an Expert and await a customized answer.

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