P2798 Porsche 959 Diagnostic Trouble Code

P2798 Porsche 959 code definition:
P2798 is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Porsche 959.

P2798 Porsche 959 is described as Oxygen Sensor Circuit No Activity Detected Bank 2 Sensor 1. This code appears when the PCM (powertrain control module, also known as ECM or engine control module in other brands) remains at or close the 0.450 set voltage point. This is because the barometric pressure sensor is part of the MAF sensor. Sometimes, the MAF's sensing wire can accumulate and get covered with dirt, dust and/or oil residue, which can also lead to the error code.

Symptoms

Symptoms of a P2798 Porsche 959 diagnostic trouble code may include:

Poor fuel economy
Possible spark knock (detonation / pre-ignition)
Misfire
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly

Possible Causes :

A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
Faulty IMRC actuator/sensor
A plugged converter will cause of host of driveability problems as well as set this code. A severely plugged converter will result in the inability to increase rpm when under load. Look for a code such as P0421 -- catalytic converter efficiency below threshold if the converter indicating a faulty converter.

Common Misdiagnoses

Crankshaft Position Sensor Circuit Performance Problem
TP Sensor Learn Not Complete Problem
Low Coolant Circuit Problem
Cruise Control System - Vehicle Accel Too High Problem
Kick-Down Switch Failed Short Problem

Repair Processes :

Look at the plug wires to make sure they are not burnt or laying on the exhaust. Now, clear the codes and test-drive the vehicle to see if the code is reset. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code P2798 Porsche 959 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before P2798 Porsche 959.

Fortunately, P2798 Porsche 959 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.