P2171: Exhaust Pressure Regulator Vent Solenoid Control Circuit High
What to do
Usually mild, with slow warm-up and a weak heater as the everyday effect. The one case worth mentioning to a workshop is a noticeable loss of power along with this code — that suggests the exhaust valve is being held closed rather than released, which is the less common direction and the one worth looking at promptly.
What this code means
The vent solenoid's control circuit reads above its valid range — a short to a voltage supply, or an open circuit that lets the line float high.
The background is under P2169 and the harness argument under P2170. The distinction worth drawing here is that this code and the open-circuit code at P2169 can arise from the same physical fault seen from different sides, depending on how the module drives the solenoid: a switched-earth output reads high when the circuit breaks, because nothing is pulling it down. So do not read P2169 and P2171 as two different problems needing two different repairs — on many vehicles they are one broken connection described twice, and finding it satisfies both.
A genuine short to voltage is the less common cause and the more damaging one, since it can hold the solenoid energised regardless of what the module commands. On this system that means the regulator stays applied, which is the one way this circuit can leave the exhaust restricted when it should not be.
Likely causes
Start here
- Open circuit in solenoid wiring · moderate
- Corroded or loose connector · easy
- Faulty exhaust pressure control solenoid · moderate
Less common
- Wiring shorted to voltage · moderate
- Heat-damaged wiring insulation · moderate
Symptoms
Components involved
Information, not instruction
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Community experience
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