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 the part of the car that helps start the engine when you turn the key or push the start button.
The P25B7 code indicates an issue with the circuit that controls the auxiliary ignition switch, which is responsible for starting the vehicle.
The P25B7 code is triggered when the Engine Control Module (ECM) detects a malfunction in the auxiliary ignition switch circuit. This circuit is responsible for communicating the ignition switch's position to the ECM, allowing it to initiate the engine start sequence.
• Engine does not start
• No response when turning the key or pressing the start button
• Intermittent starting issues
• Faulty ignition switch
• Damaged wiring or connectors in the ignition circuit
• Failed ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics II
• Inspect the ignition switch for signs of damage or wear.
• Check the wiring and connectors for corrosion or disconnection.
• Use a multimeter to test the circuit for continuity.
• Replace the faulty ignition switch.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• Multimeter
• Screwdriver set
• OBD-II scanner
$150 - $500
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regularly inspect the ignition switch for wear.
• Ensure wiring connections are secure and free of corrosion.
• Avoid using excessive force when turning the ignition key.
Electrical Circuit Issue
• If the car doesn't start, check the battery and ignition switch.
• Consult a professional mechanic if unsure about the diagnosis.
Check with your vehicle manufacturer for warranty coverage on ignition components.
This code has been associated with ignition switch failures in various vehicle models over the years.
High – This issue can prevent the vehicle from starting, requiring immediate attention.
Ensure all repairs are conducted by a qualified technician to maintain vehicle safety standards.
• Vehicle in park or neutral
• Battery fully charged
The ignition switch is typically located on the steering column or dashboard.
Q: Can I drive with a P25B7 code?
A: No, this code can prevent your car from starting, so it should be addressed immediately.
Q: Will resetting the code fix the problem?
A: Resetting the code may temporarily clear it, but the underlying issue needs to be fixed to prevent it from returning.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
Useful when wheel, hub, or suspension hardware needs correct reassembly torque.
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Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
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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.