B25A3 Diagnostic Trouble Code

B25A3 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 B25A3 diagnostic trouble code may include:

Poor acceleration
Cherry red hot catalytic converter
Possible spark knock (detonation / pre-ignition)
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.

Repair Processes :

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 missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed.

Process Tips

Diagnostic trouble code B25A3 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 B25A3.

Fortunately, B25A3 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B25A3 Trouble Code For Specific Cars

B25A3 Gaz 24 O2 Sensor Circuit Low Voltage (Bank 1 Sensor 3)
B25A3 Tvr T440 Power Sliding Door Opened During Module Close Command
B25A3 Toyota Caldina O2 Sensor Circuit Low Voltage (Bank 2 Sensor 1)
B25A3 Cord 8 Fuel Sender Circuit Open
B25A3 Alfa Romeo 90 Accelerometer Rear Circuit Short To Battery
B25A3 Mazda 626 Transmission Transfer Case Contact Plate 'D' Short Circuit To Ground
B25A3 Enzmann 506 Injection Pump Fuel Metering Control "B" Low (Cam/Rotor/Injector)