Exhaust Gas Recirculation (EGR) Valve Position Sensor Circuit
EGR valve position sensor voltage is out of range or faulty.
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What it means (plain English)
The EGR system reduces nitrogen oxide emissions by recirculating exhaust gases back into the engine. If the sensor reading that tells the computer how much the EGR valve is open or closed is off, it can cause performance issues.
What the computer is actually seeing
The engine control module (ECM) monitors the EGR valve position sensor. It expects to see a voltage drop between 0.5V (valve closed) and 4.5V (valve fully open). If the voltage goes outside this range, the fault code is triggered.
What a healthy reading looks like
Voltage should be between 0.5V to 4.5V depending on valve position.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the vehicle's wiring harness and connectors for damage and ensure they are secure. Look for signs of corrosion or shorts.
- 22. Using a multimeter, test the voltage at the EGR valve position sensor. You should see a voltage within 0.5V to 4.5V as the engine operates.
- 33. If the voltage is outside the expected range, inspect the EGR valve for proper operation (sticking, blockage).
- 44. If the sensor is faulty, replace it and clear the code. If the problem persists, check the ECM for faults.
Common causes
- Faulty EGR valve position sensor
- Wiring issues (shorts or opens)
- Improper EGR valve operation
- Faulty ECM or incorrect programming
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's not recommended to drive long distances as it can reduce engine performance and increase emissions.
Will this code return after clearing?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does this code pair with SPN 3190?
SPN 3190 is related to the EGR valve itself, while SPN 3191 specifically concerns the position sensor of that valve.
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