U3125 Diagnostic Trouble Code

U3125 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 U3125 diagnostic trouble code may include:

Fuel pressure too low
Rich or lean exhaust
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.
Faulty IMRC actuator/sensor

Repair Processes :

It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem. 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 U3125 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 U3125.

Fortunately, U3125 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U3125 Trouble Code For Specific Cars

U3125 Volvo Xc90 SCP (J1850) Invalid or Missing Data for Function Read Fuel System
U3125 Jaguar Xka Seat Driver Rear Down Circuit Failure
U3125 Renault Nepta Heated Backlite Relay Short To Battery
U3125 Nissan Rasheen Crankshaft Position Sensor B Circuit High Input
U3125 Chevrolet Hhr Dual Alternator Upper Fault
U3125 Fiat Panda 2 Lamp Turn Signal Right Circuit Open
U3125 Chevrolet Grand Blazer Dual Alternator Lower Circuit Malfunction/ Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent Low Voltage