B1128 Diagnostic Trouble Code

B1128 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 B1128 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
Hesitation upon acceleration

Possible Causes :

Some aftermarket accessories and performance modifications
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.
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Look at the plug wires to make sure they are not burnt or laying on the exhaust. 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. If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve.

Process Tips

Diagnostic trouble code B1128 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 B1128.

Fortunately, B1128 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B1128 Trouble Code For Specific Cars

B1128 Chevrolet Utility Engine Coolant Sensor intermittent/ECT Sensor Intermittent
B1128 Mercedes Sl 600 Air Bag Crash Sensor #2 Ground Circuit Open
B1128 Alfa Romeo 1600 ABS Power Relay Coil Circuit Failure
B1128 Bsa Fwd Cruise Control/Brake Switch A Circuit Malfunction
B1128 Lexus Rx 300 TFT Sensor In Range Failure High
B1128 Horch Sachsering RF PARK LAMP OUTPUT CIRCUIT Short to Battery
B1128 Chevrolet Monte Carlo EGI Temperature Sensor Failure