OBD (II) - P0354 - P1096: P0455: Diagnosis/troubleshooting: Notes
This fault code can also imply an internal leak within the tank system. In such a case, there would be no external leak despite the detection of a leaking tank. We strongly recommend to follow to the word the work instructions given in the table below.
The fuel tank leak test for the Cayenne is carried out with approx. 20 mbar overpressure in the tank. This overpressure is built up by the leakage diagnosis pump and is evaluated using an integrated reed contact. The pump work is performed by a spring, which is stretched over a membrane by the vacuum from the intake manifold (or supply tank).
There may be several smaller leaks that in combination correspond to the leak detected here which has a diameter of over 2 mm.
The diagnostic conditions can also be 'forced' by performing the "Leakage Diagnosis" short test using the 9588 Porsche System Tester II.
- Danger of intoxication through petrol!
- Inhaling vapors can lead to irritation of the mucous membranes and eyes.
- It represents a serious risk to health when inhaled, touched or swallowed over longer periods.
- Wear a breathing mask with active charcoal filter; do not breathe in any fuel vapors.
- Wear protective gloves that are fuel-resistant.
- Only work on the fuel system in well-ventilated locations.
- Before opening fuel lines or fuel hoses, relieve the fuel pressure.
- Collect escaping fuel; absorb it if necessary with a suitable binding material and dispose of properly
- Pay attention to cleanliness when working on the fuel system.
- Risk of fire and explosion when handling petrol!
- Keep clear of ignition sources.
- Do not smoke.
- Do not carry out welding or grinding work in the immediate vicinity (naked flame and flying sparks)!
- Prevent escaping fuel from coming into contact with hot engine components!
- Avoid electric discharges in the vicinity of escaped fuel!
- Secure the vehicle, e.g. with a warning sign.
- Change any clothing soaked with fuel immediately.
- In the event of a fire, use C0 2 or dry powder fire extinguishers.