B1540 Diagnostic Trouble Code

B1540 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 B1540 diagnostic trouble code may include:

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
Faulty or damaged wiring
Hesitation upon acceleration
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.
Defective ECU strategies or components will prevent proper regeneration

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. If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition.

Process Tips

Diagnostic trouble code B1540 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 B1540.

Fortunately, B1540 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B1540 Trouble Code For Specific Cars

B1540 Mitsubishi Sup B Camshaft Position - Timing Over-Advanced or System Performance (Bank 2)
B1540 Vauxhall 30 Power Window One Touch Up/Down Activated Simultaneously
B1540 Gordon-keeble Gk Passenger Door Disarm Switch ckt Short to Ground
B1540 Citroen Rally Raid Fuel Pump Secondary Circuit Intermittent
B1540 Mercedes-benz 230 Air Bag Passenger Circuit Open
B1540 Volkswagen Vento SCP (J1850) Invalid or Missing Data for Cassette Tape
B1540 Leyland P76 Throttle Control Unit Malfunction