B1040 Diagnostic Trouble Code

B1040 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 B1040 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
Reduction in engine performance, especially at low RPM levels

Possible Causes :

Defective ECU strategies or components will prevent proper regeneration
The Mass Airflow sensor is a hot wire that senses the volume of air entering the intake manifold. The computer uses this information to control fuel 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 :

Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. Look at the plug wires to make sure they are not burnt or laying on the exhaust.

Process Tips

Diagnostic trouble code B1040 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 B1040.

Fortunately, B1040 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B1040 Trouble Code For Specific Cars

B1040 Bentley 4-litre Battery Power Relay Circuit Failure
B1040 Vauxhall Astra H Powertrain Performance Mode Switch Circuit failure
B1040 Fiat 500l Lamp Air Bag Warning Indicator Circuit Short To Battery
B1040 Peugeot Ion
B1040 Mazda Rx-01 5-6 Shift
B1040 Mercedes S 600 Air Bag Crash Sensor #1 Feed/Return Circuit Failure
B1040 Lancia Fulvia Speed Wheel Sensor Rear Center Input Short Circuit To Battery