Exhaust Gas Recirculation Sensor A Circuit Low
The P0405 code means the vehicle's onboard diagnostic system has detected: Exhaust Gas Recirculation Sensor A Circuit Low. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light illuminated
- Rough idle
- Engine pinging or knocking
- Poor acceleration
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Faulty EGR position sensor Very High
- Short to ground in EGR sensor signal wire High
- Corroded EGR sensor connector Moderate
- ECM internal fault on EGR sensor input Low
Step-by-Step Diagnostic Procedure
-
Check EGR position sensor voltage on a scan tool -- should read 0.5-1.0V with valve closed
-
Inspect the EGR sensor connector for corrosion or water intrusion
-
Disconnect the sensor and check if voltage rises -- if it stays low, check wiring for short to ground
-
Verify 5V reference voltage is present at the sensor connector
-
Replace the EGR valve assembly if the sensor is integrated and tests faulty
Common Fixes by Vehicle
What techs usually find when diagnosing P0405 on specific vehicles — tap your vehicle for the fix and the exact part:
2004-2014 Ford F-150/Explorer 4.6L/5.4L easy DIY
P0405 means the EGR valve position sensor is reading lower than expected. On Ford trucks, the DPFE (differential pressure feedback EGR) sensor fails frequently. The sensor is mounted on the firewall with two rubber hoses connecting to the EGR tube. Replace with Motorcraft DPFE15 (updated design). Also clean the EGR valve passages with carb cleaner.
Labor: 20-30 min2010-2020 Chevrolet Silverado/Express 4.8L/5.3L/6.0L moderate DIY
On GM V8 engines, P0405 is typically caused by heavy carbon buildup on the EGR valve pintle preventing full movement, which causes the position sensor to read low. Remove the EGR valve and clean carbon deposits with a wire brush and carb cleaner. If the valve still reads low with a scan tool commanding it open, replace with ACDelco 214-1109.
Labor: 30-45 min2003-2015 Honda Accord/Odyssey 2.4L/3.5L moderate DIY
Honda EGR valves use a lift sensor to report position. P0405 indicates the signal wire has high resistance or is shorted to ground. Check the 6-pin connector on the EGR valve for bent or corroded pins. Also check for carbon buildup in the EGR ports in the intake manifold -- restricted flow causes the valve to read low. Replace the EGR valve if sensor is integrated.
Labor: 30 min - 1 hourFrequently Asked Questions
Can I drive with code P0405?
You can drive short distances. The ECM cannot properly control EGR flow without accurate sensor feedback, which may cause rough running. Avoid heavy acceleration where engine knock could cause damage.
Can I replace just the EGR sensor?
On some vehicles the position sensor is a separate component that can be replaced individually. On many modern vehicles, the sensor is integrated into the EGR valve and the entire assembly must be replaced.
What voltage should the EGR sensor read?
With the EGR valve fully closed, the sensor typically reads 0.5-1.0V. Fully open, it should read 4.0-4.5V. P0405 sets when the ECM sees voltage below the expected minimum.
Sources
This page is built from documented references. Verify against your own service info before repair work.
P0405 on Diesel, EV & Equipment
The same code ID appears across other engines and platforms. The diagnostic flow varies by manufacturer — these are the platform-specific breakdowns:
See All Codes & Fixes for Your Vehicle
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