P2171: Exhaust Pressure Regulator Vent Solenoid Control Circuit High

P2171 means the module sees too much voltage on the control line of the exhaust pressure regulator vent solenoid, usually because the line touches battery voltage or the solenoid shorts internally. No manufacturer documents this exact code publicly. The closest evidence comes from its sibling: Jaguar Land Rover assigns P2170 to the solenoid of the active exhaust valve on its petrol models, so on those cars P2171 belongs to the same part with the opposite electrical fault. CARB requires output components like this to be checked for circuit faults whenever they can affect emissions or other monitors. Checking means measuring the control wire with the solenoid unplugged for foreign voltage and the coil for a too low resistance. The driver mostly notices a MIL and an exhaust sound that no longer switches.

Low severity. Can I keep driving?Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

Symptoms

Check engine lamp on
Exhaust flap stays in one position

Most likely causes

Control wire shorted to a battery-fed circuit
Solenoid coil shorted internally
Output stage in the engine control module faulty

What to check, in order

Start with the simplest. You can tick off each step.

Start with the fuel cap: tighten it fully and check its seal
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Inspect the hoses and connections around the tank and the charcoal canister
Use the scanner to test the purge and vent solenoid valves
Run a smoke test to find small leaks

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P2171 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
1: Air and fuel
71: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2171?

Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

What causes code P2171?

The most common causes are: control wire shorted to a battery-fed circuit; solenoid coil shorted internally; output stage in the engine control module faulty.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.