P1621: Control Module Long Term Memory Performance/ Immobilizer Code Words Do Not Match
MediumPowertrainEngine/Powertrain
What does P1621 mean?
P1621 is a diagnostic trouble code indicating "Control Module Long Term Memory Performance/ Immobilizer Code Words Do Not Match". This code relates to your vehicle's engine/powertrain and should be diagnosed to determine the root cause. The severity level helps indicate how urgently this should be addressed.
Common causes
- Faulty engine/powertrain component
- Wiring or connector issue in the related circuit
- Failed sensor providing incorrect readings
- Software/calibration issue requiring ECU update
- Related component causing secondary fault
What should you do?
Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.
Get a diagnosis for YOUR car
Code P1621 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.