P109B Diagnostic Trouble Code

P109B is a kind of OBD-II Diagnostic P-Powertrain 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 P109B diagnostic trouble code may include:

Reduction in engine performance, especially at low RPM levels
Vacuum leak on the engine
Diminished fuel efficiency
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

An air leak forward of the DPF will change the sensor readings resulting in the code
Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
Dirty air cleaner element Damaged DPF

Repair Processes :

Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Pull the connectors apart and carefully look at the terminals (the metal parts) inside the connectors. 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. 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.

Process Tips

Diagnostic trouble code P109B 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 P109B.

Fortunately, P109B is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P109B Trouble Code For Specific Cars

P109B Hyundai S-coupe
P109B Italdesign Medici SCP (J1850) Lack of Acknowledgment for Mirrors
P109B Austin Seven Aux A/C Blower Speed 2 Circuit Short to Ground
P109B Duesenberg Sj IMCC Circuit Malfunction, Bank B
P109B Ferrari F430 Internal Control Module RAM Error
P109B Isotta-fraschini 100 Hp SCP (J1850) Invalid or Missing Data for Restraints
P109B Chrysler Cordoba Engine Speed Input Circuit No Signal