C1790 Diagnostic Trouble Code

C1790 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 C1790 diagnostic trouble code may include:

Faulty O2 Sensor
Lack of power
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
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 :

Defective ECU strategies or components will prevent proper regeneration
The Mass Airflow sensor is a hot wire that senses the volume of air entering the intake manifold. The computer uses this information to control fuel mixture.
Fuel with a large percentage of sulfur will clog the DPF quickly

Repair Processes :

With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. Pack the connector cavity with dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and reassemble.

Process Tips

Diagnostic trouble code C1790 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 C1790.

Fortunately, C1790 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1790 Trouble Code For Specific Cars

C1790 Pontiac Grand Safari Exhaust Valve Control Solenoid Circuit Range/Performance (Bank 2)
C1790 Mitsubishi Space Wagon Aux Heater Start Counter Overrun/System Locked (same as below ?)
C1790 Chrysler Aviat Engine Overboost Condition
C1790 Dutton B-plus IMRC Input Error (Bank 2)
C1790 Mazda Laputa Turbo Charger Bypass Valve Control Circuit
C1790 Fiat Legram Lamp Turn Signal Front Output Circuit Short To Battery
C1790 Bugatti Type 46 Cylinder 11 Injector Circuit Low