C1785 Diagnostic Trouble Code

C1785 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 C1785 diagnostic trouble code may include:

Misfire
Misfire
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
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
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code C1785 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 C1785.

Fortunately, C1785 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1785 Trouble Code For Specific Cars

C1785 Apperson 6 Air Suspension LR Air Compress Request Exceeded Max Timing
C1785 Bmw 7 Climate Control A/C Pressure Switch Circuit Failure
C1785 Seat Leon Injector Control Pressure Sensor Above / Below Desired
C1785 Maybach 57 Transmission Reverse I/P Circuit Malfunction
C1785 Fiat 24 Hp Lamp ABS Warning Output Circuit Open
C1785 Aston Martin Sports Air Suspension Vent Solenoid Output Circuit Short To Battery
C1785 Ac 427 A/C Temperature Sensor Out of Range