C3621 Diagnostic Trouble Code

C3621 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 C3621 diagnostic trouble code may include:

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
Faulty or damaged wiring
Hesitation upon acceleration
Engine surge

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.
Some aftermarket accessories and performance modifications

Repair Processes :

Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. 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. 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.

Process Tips

Diagnostic trouble code C3621 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 C3621.

Fortunately, C3621 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C3621 Trouble Code For Specific Cars

C3621 Maserati Merak Transmission Fluid Pressure Sensor/Switch F Circuit Intermittent
C3621 Hyundai Marcia
C3621 Alta 1100 Air Bag Passenger Pressure Switch Circuit Failure
C3621 Honda Vigor Reverse Output Circuit
C3621 Delage 3-litre Hydraulic Oil Temperature Sensor Circuit High Input
C3621 Apollo B Air Suspension LF Height Sensor Circuit Short To Battery
C3621 Morris Six Calibration Resistor Out Of Range