C3789 Diagnostic Trouble Code

C3789 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 C3789 diagnostic trouble code may include:

Corroded or damaged connector
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Lack of power
Engine surge

Possible Causes :

Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
An air leak forward of the DPF will change the sensor readings resulting in the code
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.

Repair Processes :

Look at the plug wires to make sure they are not burnt or laying on the exhaust. If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code C3789 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 C3789.

Fortunately, C3789 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C3789 Trouble Code For Specific Cars

C3789 Opel Astra K Decklid Ajar Rear Door Circuit Open
C3789 Chrysler Custom Engine Temperature Light Monitor Failure
C3789 Toyota Fortuner Oil Change Lamp Circuit Short To Battery
C3789 Dome Zero Ignition Tamper Circuit Open
C3789 Mercedes Glk Accelerometer Sensor Circuit Failure
C3789 Lada 110 Servo Motor Potentiometer Vent Circuit Failure
C3789 Suzuki Alto Memory 1 Switch Circuit Failure