U120D Chevrolet Cruze Diagnostic Trouble Code

U120D Chevrolet Cruze code definition:
U120D is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code for Chevrolet Cruze.

U120D Chevrolet Cruze is defined as Ignition Coil B Primary/Secondary Circuit Malfunction.This code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II tool, or vehicles made since 1996 up to present. If the car doesn't start, they will proceed by testing the voltage at the fuel pump connector and see if the fuel pump relay, fuse, and PCM circuitry should be inspected.

Symptoms

Symptoms of a U120D Chevrolet Cruze diagnostic trouble code may include:

If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Corroded or damaged connector
Reduction in engine performance, especially at low RPM levels
Rich or lean exhaust

Possible Causes :

The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Fuel with a large percentage of sulfur will clog the DPF quickly
Some aftermarket accessories and performance modifications

Common Misdiagnoses

Vehicle Speed Output Circuit Problem
Cruise Control Servo Indicates Low Problem
A/C System High Pressure High Temperature Problem
PCM Stack Overrun Problem
Transmission Control Module Reprogrammable Memory 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. If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for.

Process Tips

Diagnostic trouble code U120D Chevrolet Cruze 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 U120D Chevrolet Cruze.

Fortunately, U120D Chevrolet Cruze is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.