Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer has detected a problem with the sensor that checks the electrical current in cylinder 11 of the engine. It's like a sensor that helps the car know how well the engine is running, and it's not working right now.
The ion current sense circuit monitors the combustion process in the cylinder by measuring the ionization current. A 'high' signal indicates an abnormally high voltage or current in the circuit.
The P28BB code is triggered when the Engine Control Module (ECM) detects a voltage or current level that is higher than expected in the ion current sense circuit for cylinder 11. This could be due to a short circuit, faulty sensor, or wiring issues.
• Check Engine Light illuminated
• Poor engine performance
• Increased fuel consumption
• Faulty ion current sensor
• Short circuit in the wiring
• ECM malfunction
ECM: Engine Control Module
Ion Current Sensor: A sensor that measures the ionization current in the combustion chamber to monitor combustion quality.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections for cylinder 11's ion current sensor.
• Test the ion current sensor for proper operation.
• Replace the faulty ion current sensor.
• Repair or replace damaged wiring.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• BMW 7 Series
• Mercedes-Benz S-Class
• Audi A8
• Regular maintenance checks
• Ensure proper electrical connections
• Use quality fuel to prevent sensor contamination
Sensor Issue
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional mechanic.
• Avoid driving the vehicle aggressively until the issue is resolved.
Check with your vehicle's manufacturer for warranty coverage on engine sensors.
This code is relatively uncommon and typically associated with high-performance or luxury vehicles with advanced engine monitoring systems.
Moderate – While the vehicle may still be drivable, it is recommended to address the issue promptly to avoid potential engine damage.
Ignoring this code can lead to increased emissions and may cause the vehicle to fail emissions tests.
• Engine at operating temperature
• Vehicle in motion
The ion current sensor is typically located near the spark plug or ignition coil of cylinder 11.
Q: Can I drive with a P28BB code?
A: It's not recommended to drive for extended periods with this code, as it may lead to engine performance issues.
Q: How can I reset the P28BB code?
A: You can reset the code using an OBD-II scanner, but it's important to fix the underlying issue first to prevent the code from returning.
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Universal · Digital multimeter
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Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.