EGR Position Sensor
This code indicates an issue with the EGR position sensor response.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The EGR position sensor measures how much exhaust gas is being recirculated into the engine. If the sensor isn't sending the right signals, the engine might not run efficiently or produce more emissions.
What the computer is actually seeing
The engine control unit (ECU) monitors the position of the EGR valve through the position sensor, expecting a voltage range of 0.5 to 4.5 volts depending on the position of the valve.
What a healthy reading looks like
Expected voltage signals from the EGR position sensor should range from 0.5V (closed) to 4.5V (fully open).
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. Inspect the wiring harness and connectors to the EGR position sensor for damage or corrosion. If found, repair or replace as needed. Decision point: If wiring issues are fixed, check for codes again. If not, proceed to step 2.
- 22. Test the EGR position sensor output voltage while the engine is running. You should see voltage between 0.5V and 4.5V. Decision point: If voltage is outside of this range, replace the EGR position sensor. If voltage is within range, proceed to step 3.
- 33. Check the EGR valve operation. Manually operate the valve (if applicable) or monitor the valve operation with a scan tool. Look for proper opening and closing. Decision point: If the EGR valve is stuck or faulty, replace the EGR valve. If it operates correctly, check for carbon buildup in the EGR passages.
Common causes
- Faulty EGR position sensor
- Wiring issues or shorts in the sensor circuit
- Faulty EGR valve
- Contamination or carbon buildup in the EGR system
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's safe to drive for a short period, but fixing it soon is important to avoid increased emissions and potential engine performance issues.
Will this code come back after clearing it?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does this code often appear with others?
SPN 946 can be linked to other EGR-related codes, indicating multiple symptoms of a failing exhaust gas recirculation system.
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