C1789 Diagnostic Trouble Code

C1789 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 C1789 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.
Rich or lean exhaust

Possible Causes :

The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Fuel with a large percentage of sulfur will clog the DPF quickly
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. 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.

Process Tips

Diagnostic trouble code C1789 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 C1789.

Fortunately, C1789 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1789 Trouble Code For Specific Cars

C1789 Alfa Romeo Montreal Air Bag Crash Sensor #1 Ground Circuit Open
C1789 Seat Cordoba 2 Injector Circuit Open / Shorted - Cylinder #5
C1789 Nsu Tt Cylinder 12 Misfire Detected
C1789 Isdera Imperator
C1789 Simca 1301 Intake Manifold Runner Control (Stuck Open)
C1789 Moretti 127 Battery Saver Relay Coil Circuit Short To Ground
C1789 Ruf Ctr Ignition Retard Request Duration Fault