C1678 Diagnostic Trouble Code

C1678 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 C1678 diagnostic trouble code may include:

Carbon Buildup on O2 Sensor
Malfunction Indicator Lamp (MIL) illuminated
Hesitation upon 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
Some aftermarket accessories and performance modifications

Repair Processes :

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. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed. 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.

Process Tips

Diagnostic trouble code C1678 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 C1678.

Fortunately, C1678 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1678 Trouble Code For Specific Cars

C1678 Ferrari Tipo Keyless Entry Circuit Short To Ground
C1678 Nissan Safari Crankshaft Position Sensor B Circuit Malfunction
C1678 Toyota Es3 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)
C1678 Marcos Mini-marcos Transmission 4-Wheel Drive High Indicator Short Circuit To Battery
C1678 Mitsubishi Suw B Camshaft Position - Timing Over-Retarded (Bank 1)
C1678 Ford 2000 Left Rear Turn Lamp Circuit Short to Battery
C1678 Mazda 3 Transmission Transfer Case Contact Plate 'B' Short Circuit To Ground