Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with how the car's computer senses the spark in cylinder 7. It's like trying to hear a whisper from far away and not being able to hear it well.
The ion current sensing circuit monitors the combustion process in the cylinder. A low signal indicates that the expected ion current is not being detected properly.
The P28AA code is triggered when the Engine Control Module (ECM) detects a low ion current signal from cylinder 7. This ion current is used to monitor the combustion process and ensure efficient ignition. A low signal could indicate issues with the spark plug, ignition coil, or wiring.
• Engine misfire
• Rough idling
• Reduced engine performance
• Faulty spark plug in cylinder 7
• Defective ignition coil for cylinder 7
• Damaged or corroded wiring or connectors in the ion sense circuit
ECM: Engine Control Module
Ion Current: A measure of the ionization in the combustion chamber, used to monitor combustion quality.
• Use an OBD-II scanner to confirm the code.
• Inspect the spark plug in cylinder 7 for wear or damage.
• Check the ignition coil for proper operation.
• Examine the wiring and connectors for damage or corrosion.
• Replace the spark plug in cylinder 7 if faulty.
• Replace the ignition coil for cylinder 7 if defective.
• Repair or replace damaged wiring or connectors in the ion sense circuit.
• OBD-II scanner
• Multimeter
• Spark plug socket
$100 - $300
Moderate
• Chevrolet Silverado
• GMC Sierra
• Cadillac Escalade
• Regularly inspect and replace spark plugs as needed.
• Maintain the ignition system components.
• Keep the engine bay clean to prevent corrosion.
Sensor Issue
• Have the vehicle inspected by a professional if you notice engine performance issues.
• Avoid driving long distances until the issue is resolved to prevent further damage.
Check with your vehicle manufacturer for warranty coverage on ignition system components.
This code is often associated with ignition system issues and has been more prevalent in vehicles with high mileage.
Moderate – Addressing this issue promptly can prevent further engine damage.
Ignoring this issue can lead to increased emissions and potential engine damage. Ensure repairs are performed by a qualified technician.
• Engine at operating temperature
• Vehicle stationary
The ion current sensing circuit components are located near the ignition coil and spark plug of cylinder 7.
Q: Can I drive my car with a P28AA code?
A: It's not recommended to drive for long distances, as it may cause further engine damage.
Q: How can I prevent this code from appearing again?
A: Regular maintenance of the ignition system and timely replacement of spark plugs can help prevent this issue.
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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.