C1986 Diagnostic Trouble Code

C1986 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 C1986 diagnostic trouble code may include:

Poor acceleration
Cherry red hot catalytic converter
Possible spark knock (detonation / pre-ignition)
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.
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.

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. Once located, visually inspect the connectors and wiring. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors.

Process Tips

Diagnostic trouble code C1986 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 C1986.

Fortunately, C1986 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1986 Trouble Code For Specific Cars

C1986 Seat Toledo 2 Input/Turbine Speed Sensor Circuit Range/Performance
C1986 Vanden Plas Limousine Power Window Master Circuit Open
C1986 Boll Limousine Compressor Failure
C1986 Fiat Grande Punto Lamp Turn Signal Front Output Circuit Failure
C1986 Alvis 32hp Air Bag Safing Sensor Output Circuit Open
C1986 Honda Hp-x PRNDL Switch Circuit Failure
C1986 Opel Frogster Dim Panel Decrease Input Circuit Short To Battery