U3698 Diagnostic Trouble Code

U3698 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 U3698 diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
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
An air leak forward of the DPF will change the sensor readings resulting in the code

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. Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Pull the connectors apart and carefully look at the terminals (the metal parts) inside the connectors. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code U3698 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 U3698.

Fortunately, U3698 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U3698 Trouble Code For Specific Cars

U3698 Aston Martin 2-litre Air Suspension RF Height Sensor Circuit Failure
U3698 Lada 21 Shift Solenoid A Control Circuit Low
U3698 Chevrolet Vivant Engine Coolant Temperature Circuit High Input
U3698 Mercedes Sl 320 Air Bag Crash Sensor #1 Ground Circuit Short To Ground
U3698 Zhonghua Coupe
U3698 Vauxhall Viceroy Pressure Control Solenoid Intermittent
U3698 Mercedes Cls 55 ABS Outlet Valve Coil RR Circuit Open