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 having trouble reading signals from cylinder 8, which helps it know how well that part of the engine is working.
The ion current sense circuit monitors the combustion quality in the cylinder by measuring ionization currents. This code indicates an issue with the circuit's performance in cylinder 8.
The P28AD code is triggered when the Engine Control Module (ECM) detects a range or performance issue in the ion current sense circuit for cylinder 8. This circuit is responsible for detecting the ionization current that occurs during combustion, which helps the ECM optimize ignition timing and fuel delivery.
• Check Engine Light is on
• Poor engine performance
• Increased fuel consumption
• Faulty ion current sensor
• Wiring issues in the ion current sense circuit
• ECM software or hardware malfunction
ECM: Engine Control Module
Ionization: The process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connections for cylinder 8's ion current sensor.
• Test the ion current sensor for proper operation.
• Replace the faulty ion current sensor.
• Repair or replace damaged wiring or connectors.
• Update or reprogram the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance checks
• Ensure proper connections and wiring
• Use quality fuel to prevent sensor fouling
Engine Performance
• Do not ignore the Check Engine Light.
• Have the vehicle inspected by a professional if you notice performance issues.
Check with your vehicle manufacturer for warranty coverage on engine components.
This code is relatively uncommon and typically associated with specific engine management systems.
Moderate – It is important to address this issue to prevent further engine performance problems.
Driving with a malfunctioning engine can lead to increased emissions and potential safety hazards.
• Engine at operating temperature
• Steady driving conditions
The ion current sensor for cylinder 8 is located near the spark plug or ignition coil of the eighth cylinder.
Q: Can I drive with a P28AD code?
A: While the car may still be drivable, it's best to have it checked to avoid further damage.
Q: How can I reset the Check Engine Light?
A: You can use an OBD-II scanner to clear the code, but it's important to fix the underlying issue first.
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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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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.