U1807 Diagnostic Trouble Code

U1807 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 U1807 diagnostic trouble code may include:

Faulty or damaged wiring
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
Poor fuel economy
Rich or lean exhaust

Possible Causes :

Faulty IMRC actuator relay (if equipped)
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Repair Processes :

If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground.

Process Tips

Diagnostic trouble code U1807 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 U1807.

Fortunately, U1807 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U1807 Trouble Code For Specific Cars

U1807 Proton Inspira Fuel Shut Off Solenoid Malfunction
U1807 La Salle Saloon Servo Motor Potentiometer Foot Circuit Short To Ground
U1807 Porsche 356 Front Lateral Accelerometer Circuit Failure
U1807 Rolls-royce 20 Hydraulic Pressure Unit Cycling Period Too Short
U1807 Hyundai Sonata 6 SCP (J1850) Invalid or Missing Data for Electric Defrost
U1807 Renault R5 Heated Wind Shield Relay Short to Vbatt (changed from Failure 2/6/97)
U1807 Kia Capital Seat Rear Vertical Motor Memory Position Out of Range