B0120 Diagnostic Trouble Code

B0120 is a kind of OBD-II Diagnostic B-Body 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 B0120 diagnostic trouble code may include:

Fuel pressure too high
Diminished fuel efficiency
Rich or lean exhaust
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 :

A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
Faulty IMRC actuator/sensor
Faulty IMRC actuator relay (if equipped)

Repair Processes :

Look at the plug wires to make sure they are not burnt or laying on the exhaust. 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. 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 B0120 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 B0120.

Fortunately, B0120 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B0120 Trouble Code For Specific Cars

B0120 Facel Vega Excellence Injection Timing Control Circuit Malfunction
B0120 Maserati Mc12 Transmission Fluid Pressure Sensor/Switch F Circuit High
B0120 Goggomobil Mayfair Passenger Air Bag Disable Module Fault
B0120 Acura Mdx Iii ABS Inlet Valve Coil LF Circuit Failure
B0120 Auburn 4-44 Airbag Deployment Indication Input Fault
B0120 Cunningham C3 Fuel Temperature Sensor #1 Circuit Open
B0120 Locomobile 30 Timing Reference High Resolution Signal A Intermittent/Erratic Pulses