C0109 Diagnostic Trouble Code

C0109 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 C0109 diagnostic trouble code may include:

Excessive exhaust leak
Hesitation upon acceleration
Malfunction Indicator Lamp (MIL) illuminated
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.

Repair Processes :

Use the DVOM to test resistance and continuity on all system circuits if actuator and sensor resistance levels are in compliance with manufacturer's specifications. 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.

Process Tips

Diagnostic trouble code C0109 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 C0109.

Fortunately, C0109 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0109 Trouble Code For Specific Cars

C0109 Hyundai Sonata 6 SCP (J1850) Invalid or Missing Data for Electric Defrost
C0109 Wolseley 12
C0109 Nsu Autonova Cylinder 11 Injector Circuit High
C0109 Ika Torino SCP (J1850) Invalid or Missing Data for Engine Torque
C0109 Mazda Mx-3 1-2 Shift Malfunction
C0109 Riley Pathfinder Hydraulic Clutch Actuator Valve Signal Fault
C0109 Seat Arosa Injector Circuit Open / Shorted - Cylinder #1