30BB

What the Code Means

Code 30BB points to an internal fault in the engine control module (DME) — a failed fuel injector MOSFET driver on bank 2. This error is specific to MSD80 units and mirrors code 30BA, but on the other cylinder bank. The MOSFET driver controls fuel injection; when it fails, fuel delivery to the bank 2 cylinders stops. The affected system is the direct-injection fuel system. Main components: DME (MSD80), MOSFET driver, bank 2 fuel injectors.

Symptoms

• Misfires in the bank 2 cylinders
• Loss of engine power
• Rough running (engine stumble)
• Check Engine light on

Diagnosis and Repair

Step 1: Read the Codes

Use ISTA or INPA to confirm code 30BB and check for related faults.

Step 2: Test the Injectors

With an oscilloscope, check voltage and current at the bank 2 injectors. No signal points to a failed driver.

Step 3: Replace the DME or MOSFET Driver

Once the MOSFET driver failure is confirmed, you can replace the DME (with programming) or have a qualified specialist solder in a new driver.

Step 4: Replace the Injectors

If the injectors failed because they lost their control signal, replace them.

Common diagnostic mistake: Replacing the injectors without testing the driver — the problem will come back.

Secondary Problems

Ignoring code 30BB can lead to:

• Bank 2 injector failure from loss of control signal
• Misfires, which send unburned fuel into the exhaust
• Catalytic converter damage (clogging, overheating)
• Complete DME failure requiring module replacement

Severity: High. Diagnose and repair immediately to prevent costly damage.