U0221 Diagnostic Trouble Code

U0221 is a kind of OBD-II Diagnostic U-Network 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 U0221 diagnostic trouble code may include:

Fuel pressure too low
Rich or lean exhaust
Diminished fuel efficiency
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)
Faulty IMRC actuator/sensor

Repair Processes :

Once located, visually inspect the connectors and wiring. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. 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 U0221 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 U0221.

Fortunately, U0221 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U0221 Trouble Code For Specific Cars

U0221 Simca 1500 Intake Valve Control Solenoid Circuit High (Bank 1)
U0221 Abarth A112 A Camshaft Position Actuator Circuit (Bank1)
U0221 Mercedes-benz Clc Class Air Pump Circuit Malfunction/ (AIR) System Bank 1
U0221 Citroen Aventure Four Wheel Drive (4WD) Switch Circuit
U0221 Kia Rio Iii Secondary Air Injection System Relay B Circuit Malfunction
U0221 Emf 30 Injection Pump Fuel Metering Control "A" Range/Performance (Cam/Rotor/Injector)
U0221 Nissan Terrano Cylinder #1 High To Low Side Short