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 computer in your car is having trouble talking to one of the fuel injectors in the engine. It's like when a light bulb doesn't turn on because there's a problem with the wiring.
The P21DA code indicates an issue with the electrical circuit of the fuel injector for cylinder 12, specifically injector B. This could mean a break or disconnection in the wiring or a problem with the injector itself.
The P21DA code is triggered when the Engine Control Module (ECM) detects an open circuit or a fault in the electrical circuit of the fuel injector designated as Injector B for cylinder 12. This can be due to wiring issues, connector problems, or a faulty injector.
• Engine misfire
• Poor fuel economy
• Check Engine Light illuminated
• Faulty fuel injector
• Damaged wiring or connectors
• ECM malfunction
ECM: Engine Control Module
OBD-II: On-Board Diagnostics II
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for cylinder 12 injector B.
• Test the fuel injector for proper operation.
• Repair or replace damaged wiring/connectors.
• Replace the faulty fuel injector.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Chevrolet Silverado
• Ford F-250
• Ram 3500
• Regular maintenance checks
• Ensure proper fuel quality
• Inspect wiring harnesses periodically
Engine Performance
• Avoid driving the vehicle until repaired to prevent further damage.
• Consult a professional mechanic for accurate diagnosis and repair.
Check if the vehicle is still under warranty for powertrain components.
This code has been associated with vehicles that have high mileage or those that have had previous engine work done.
Moderate – Address the issue soon to prevent engine performance problems.
Driving with a malfunctioning injector can lead to further engine damage and increased emissions.
• Engine at operating temperature
• Vehicle stationary and in park
The fuel injector for cylinder 12 is located on the engine block, typically under the intake manifold.
Q: Can I drive with a P21DA code?
A: It's not recommended to drive with this code as it may cause further engine damage.
Q: How can I prevent injector circuit issues?
A: Regular maintenance and inspections can help prevent these issues.
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Universal · Digital multimeter
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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.