U2120 Frazer Nash Competition Diagnostic Trouble Code

U2120 Frazer Nash Competition code definition:
U2120 is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code for Frazer Nash Competition.

U2120 Frazer Nash Competition is defined as Cylinder 3 Injector Circuit Malfunction. This code means the PCM (powertrain control module, also known as ECM or engine control) has detected a problem in the injector or its wiring, or in injector circuit for cylinder 3. The spark should have a light tan color. If the sensor probe comes with white and chalky parts, this means it has been lagging between switching phases, and should be replaced.

Symptoms

Symptoms of a U2120 Frazer Nash Competition diagnostic trouble code may include:

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

Possible Causes :

Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

Common Misdiagnoses

IC Circuit High Voltage Problem
Control Module Throttle Actuator Position Performance Problem
Air Conditioning (A/C) Clutch Feedback Circuit High Voltage Problem
Cruise Vehicle Speed/Set Speed Difference Too High Problem
PCM Stack Overrun Problem

Repair Processes :

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. 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. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code U2120 Frazer Nash Competition 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 U2120 Frazer Nash Competition.

Fortunately, U2120 Frazer Nash Competition is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.