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 way it senses electrical signals in the fourth cylinder. It's like the car's brain is having trouble 'listening' to one of its parts.
The ion current sense circuit monitors the combustion process in the engine's cylinder by detecting ionization levels. For cylinder 4, this code indicates that the circuit is not performing within the expected range.
P289D is triggered when the Engine Control Module (ECM) detects that the ion current sense circuit for cylinder 4 is operating outside of its specified range. This circuit is crucial for monitoring the combustion process and ensuring optimal engine performance by providing feedback on the ionization levels during the combustion cycle.
• Check Engine Light is on
• Poor engine performance
• Increased fuel consumption
• Faulty ion current sensor
• Wiring issues in the ion current circuit
• ECM malfunction
ECM: Engine Control Module
Ion Current Sensor: A sensor that detects ionization levels in the combustion chamber to monitor combustion quality
• Use an OBD-II scanner to confirm the code
• Inspect the wiring and connections for cylinder 4's ion current sensor
• Test the ion current sensor for proper operation
• Repair or replace damaged wiring
• Replace the ion current sensor
• Reprogram or replace the ECM if necessary
• OBD-II scanner
• Multimeter
• Wiring diagram for the vehicle
$150 - $500
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance checks
• Ensure proper engine tune-ups
• Check wiring harnesses periodically
Engine Performance
• Avoid driving long distances until the issue is resolved
• Consult a professional mechanic for accurate diagnosis
Check with the vehicle manufacturer for specific warranty coverage related to engine sensors.
This code has been associated with vehicles that utilize ion current sensing technology to optimize combustion efficiency.
Moderate – It is advisable to address this issue soon to prevent potential engine damage.
Driving with a malfunctioning engine sensor can lead to increased emissions and may not comply with vehicle emissions standards.
• Engine at operating temperature
• Vehicle stationary with engine idling
The ion current sensor for cylinder 4 is typically located near the ignition coil or spark plug of the fourth cylinder.
Q: Can I drive with a P289D code?
A: It's not recommended to drive for extended periods with this code, as it may lead to further engine issues.
Q: How do I reset the Check Engine Light after fixing the issue?
A: Use an OBD-II scanner to clear the code from the vehicle's computer after repairs are completed.
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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.