B1520 Diagnostic Trouble Code

B1520 is a kind of OBD-II Diagnostic B-Body 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 B1520 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
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.
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 you find a related TSB, the information will often help in diagnosing the code in question as TSBs are crested from many thousands of repairs. 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 B1520 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 B1520.

Fortunately, B1520 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B1520 Trouble Code For Specific Cars

B1520 Bmw C 650 Gt Climate Control Pushbutton Circuit Failure
B1520 Rover 825 Ignition Coil D Primary/Secondary Circuit Malfunction
B1520 Bmw Serie 6 Clutch Solenoid Circuit Malfunction
B1520 Mercedes-benz 300 Air Bag Passenger Circuit Short to Ground - Loop #2
B1520 Daihatsu Taft Glow Plug/Heater Circuit "A" Malfunction
B1520 Singer Gazelle Internal Vref Malfunction
B1520 Ford Monarch Mirror Driver Vertical Switch Circuit Open