The engine computer has detected an abnormally high voltage signal in the exhaust pressure regulator vent solenoid circuit. This typically indicates an open circuit or a short to voltage, preventing the solenoid from properly controlling exhaust pressure.
The solenoid coil has developed an internal open circuit or high resistance, causing the circuit voltage to spike.
Wires leading to the solenoid are frayed, broken, or rubbed through, creating an open circuit.
Moisture or road salt has corroded the electrical pins at the solenoid connector, interrupting the circuit.
A blown fuse in the emissions control circuit may prevent the solenoid from receiving the correct reference voltage.
The engine control module has an internal failure in the solenoid driver circuit.
No. P2171 is an electrical circuit code regarding the solenoid's wiring and operation, not a mechanical code for pressure buildup.
No. It is very rare for the PCM to be the cause of P2171; most cases are solved by replacing the solenoid or repairing damaged wiring.
Yes, but the vehicle may enter a reduced power mode to protect the exhaust system, and it will not pass an emissions test.