C1799 Diagnostic Trouble Code

C1799 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a C1799 diagnostic trouble code may include:

Possible spark knock (detonation / pre-ignition)
Poor fuel economy
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
Rich or lean exhaust

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
Defective ECU strategies or components will prevent proper regeneration

Repair Processes :

Use the DVOM to test resistance and continuity on all system circuits if actuator and sensor resistance levels are in compliance with manufacturer's specifications. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.

Process Tips

Diagnostic trouble code C1799 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 C1799.

Fortunately, C1799 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1799 Trouble Code For Specific Cars

C1799 Nag Voran Camshaft Position Sensor Circuit Low Input
C1799 Ariel Atom Air Suspension LR Air Spring/Shock Solenoid Output Circuit Short To Ground
C1799 Vauxhall Zafira B PRNDL Input #2 Circuit Failure
C1799 Panhard L6 Driver Power Window One Touch Window Relay Circuit Short To Ground
C1799 Autobianchi Primula Aux Heater Flame Out Fault
C1799 Mercedes S 65 Air Bag Crash Sensor #1 Feed/Return Circuit Short To Ground
C1799 Metropolitan 1200 Air Suspension RF Height Sensor Circuit Short To Battery