U1490 Diagnostic Trouble Code

U1490 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 U1490 diagnostic trouble code may include:

Faulty PCM
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Poor acceleration
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
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.

Repair Processes :

Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. 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. 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 U1490 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 U1490.

Fortunately, U1490 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U1490 Trouble Code For Specific Cars

U1490 Peugeot 107 Dynamic Stability Control Right Front Valve Malfunction
U1490 Porsche Mega Fuel Pump Secondary Circuit Malfunction
U1490 Subaru Leone Left Rear Turn Lamp Circuit Short to Battery
U1490 Talbot T 26 Mirror Passenger Right Circuit Short To Battery
U1490 Allard K Air Bag Diagnostic Monitor Ground Circuit Short To Ground
U1490 Morris Cowley Brake Pedal Input Circuit Ground Short
U1490 Osca Mt Door Unlock Disarm Output Circuit Short To Battery