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 is not getting a good signal from a sensor that checks how well cylinder 11 is firing. It's like trying to listen to a song on the radio, but the signal is weak and you can't hear it clearly.
The ion current sense circuit monitors the combustion process in the cylinder by measuring the ionization current. A low signal indicates a problem with this monitoring system.
The P28BA code is triggered when the Engine Control Module (ECM) detects that the ion current sense circuit for cylinder 11 is below the expected range. This circuit is responsible for detecting the ionization current, which helps in monitoring the combustion process and ensuring efficient engine performance.
• Check Engine Light illuminated
• Poor engine performance
• Misfiring in cylinder 11
• Faulty ion current sensor
• Wiring issues or poor connections in the circuit
• Faulty Engine Control Module (ECM)
Ion Current: A measure of the ionization in the combustion chamber, used to monitor combustion quality.
ECM: Engine Control Module, the computer that manages engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for cylinder 11's ion current sensor.
• Test the ion current sensor for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the faulty ion current sensor.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $500
Moderate
• BMW 7 Series
• BMW 5 Series
• BMW X5
• Regular maintenance checks
• Ensure proper electrical connections
• Use high-quality fuel
Sensor Issue
• Avoid driving aggressively until the issue is fixed.
• Schedule a diagnostic check with a professional mechanic.
Check with the vehicle manufacturer for specific warranty coverage related to emissions and sensors.
This code is relatively uncommon and typically associated with high-performance engines that use advanced monitoring systems.
Moderate – While the vehicle may still be drivable, it's important to address this issue to prevent potential engine damage.
Ignoring this code may lead to increased emissions and potential engine damage, which could affect vehicle safety and compliance with emissions regulations.
• Engine running
• Vehicle at operating temperature
The ion current sensor for cylinder 11 is typically located near the spark plug on the engine block.
Q: Can I drive with a P28BA code?
A: It's possible to drive, but it's not recommended as it may lead to further engine damage.
Q: How do I reset the check engine light after fixing the issue?
A: You can use an OBD-II scanner to clear the code and reset the light.
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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.