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 detecting a problem with the way it senses the spark in cylinder number 7. It's like trying to hear a whisper in a noisy room.
The ion current sense circuit is used to monitor the combustion quality in the cylinder. A high signal indicates an issue with the circuit's ability to properly detect ionization levels.
The P28AB code is triggered when the Engine Control Module (ECM) detects an abnormally high voltage signal from the ion current sense circuit for cylinder 7. This circuit is responsible for measuring the ionization current, which helps in assessing the combustion process within the cylinder. A high reading could indicate a short circuit, faulty sensor, or wiring issues.
• Check Engine Light is on
• Poor engine performance
• Increased fuel consumption
• Faulty ion current sensor
• Short circuit in the wiring
• Faulty ECM
ECM: Engine Control Module
Ion Current: A measure of ionization in the combustion chamber indicating combustion quality
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the ion current sensor for proper operation.
• Replace the faulty ion current sensor.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wiring repair tools
$150 - $500
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance checks
• Ensure proper engine tune-ups
• Use high-quality fuel
Sensor Issue
• Do not ignore the Check Engine Light.
• Have a professional diagnose and repair the issue.
• Avoid driving the vehicle if performance issues are severe.
Check with your vehicle manufacturer for specific warranty coverage on emission-related components.
This code has been associated with vehicles that have advanced ignition systems that use ion sensing technology.
Moderate – It should be addressed soon to avoid potential engine damage.
Driving with a malfunctioning engine sensor can lead to increased emissions and may not comply with local emissions laws.
• Engine at operating temperature
• Vehicle in idle or low-speed operation
The ion current sensor is typically located near the ignition coil or integrated into the spark plug of cylinder 7.
Q: Can I drive with a P28AB code?
A: It's not recommended as it could lead to further engine damage or increased emissions.
Q: How can I clear a P28AB code?
A: After repairs, use an OBD-II scanner to clear the code. If the problem persists, the issue may not be resolved.
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Network faults often require full-system access instead of a generic code reader alone.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Universal · Wire connectors and repair kit
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.