P0404: The EGR valve or its position sensor is not working within the expected range
EGR circuit range/performance
Severity: Monitor
P0404 is an emissions fault: the EGR valve is not moving to where the engine computer commands, or its position reading does not make sense. Many cars drive normally, but a valve stuck open can cause rough running, so have it fixed without too much delay.
It gets more serious if:
- Inspect soon: Have it inspected soon if the engine surges, idles rough, is hard to start, stalls or loses power. A stuck-open EGR valve causes these, and Ram and Land Rover bulletins tie P0404 to surging, hard starting and restricted performance.
P0404 in short
P0404 means the EGR valve is not reaching the position the engine computer commands, or its position sensor reading is out of range. Carbon build-up, a failed valve or position sensor and connector faults are the usual causes. Many cars drive normally, but get it checked soon if the engine surges, stalls or loses power.
The exhaust gas recirculation (EGR) valve lets a metered amount of exhaust back into the intake. This lowers combustion temperatures and cuts nitrogen oxide emissions.
Most modern EGR valves are electrically driven and have a position sensor. The engine computer compares the commanded opening with the measured position. When they don't match, or the sensor reading is out of range, it sets P0404. Honda describes it as an EGR valve circuit range/performance problem; Ram describes it as EGR position sensor performance.
Carbon is the most common culprit. Delphi calls it the single biggest cause of EGR failure, because deposits stop the valve from moving freely or seating.
A valve stuck partly open lets exhaust in when it shouldn't, causing rough idle, surging or lost power. A valve stuck shut usually causes no symptoms except possible knocking under load.
Most likely causes
Cause 1: Carbon build-up holding the EGR valve
Common general cause- Why it ranks here
- Delphi names carbon as the single biggest cause of EGR failure, and GM's Equinox bulletin points to a stuck pintle.
- What would change this
- Rises on higher-mileage engines and if deposits are found on the valve. Falls if the valve is clean and moves freely.
Cause 2: Failed EGR valve or built-in position sensor
Supported by vehicle data- Why it ranks here
- Ram replaces the EGR valve for P0404 under a warranty extension, and Honda found its engine computer could command too much lift and damage the valve internally.
- What would change this
- Rises if the valve does not follow scan-tool commands or the position reading is erratic. Falls if it tracks commands smoothly.
Cause 3: EGR connector or wiring fault
Supported by vehicle data- Why it ranks here
- Isuzu found that returned EGR valves were fine and spread connector terminals were the real cause of repeat P0404 codes.
- What would change this
- Rises if the code comes and goes or terminals are loose or corroded. Falls if the connector is tight and wiring checks out.
Cause 4: Engine computer software
Supported by vehicle data- Why it ranks here
- Honda's A13-095 updates the engine computer to stop it commanding excessive lift on the Odyssey. Without the update a new valve can fail again.
- What would change this
- Rises on a covered Odyssey without the update. Falls if no bulletin applies.
Cause 5: Debris jamming the valve
Possible — needs testing- Why it ranks here
- Ford found weld slag from the turbo pipe jamming EGR valves on new 6.4L diesels. This is specific to that engine.
- What would change this
- Rises on a low-mileage 6.4L Ford diesel. Falls on other engines.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all stored codes and ask a dealer whether your VIN has a bulletin, software update or warranty extension for P0404.
IfA software bulletin applies
It meansHave the update done along with any valve repair.
IfA valve warranty extension applies
It meansHave the valve replaced under it.
IfNothing applies
It meansCheck the connector.
Step 2: With the engine off, unplug the EGR valve connector and check the terminals for spread, looseness or corrosion.
IfTerminals are spread, loose or corroded
It meansRepair the connector.
IfThe connector is good
It meansCommand the valve with a scan tool.
Step 3: Command the EGR valve open and closed with a scan tool and watch the desired and actual position readings.
IfThe actual position lags, sticks or jumps
It meansRemove and inspect the valve.
IfIt tracks smoothly
It meansThe fault may be intermittent; check wiring under movement.
Step 4: Remove the EGR valve and look for carbon deposits or debris on the valve and seat.
Warning:EGR valves and exhaust parts get very hot. Let the engine cool fully first.
IfHeavy carbon or debris is found
It meansClean or replace the valve and clean the passages.
IfThe valve is clean but still sticks or misreads
It meansReplace the valve.
Symptoms
- Check engine light with no change in how the car drives
- Rough idle
- Surging or hard starting Gets more serious: stop and have it checked.
- Reduced power or a restricted performance warning Gets more serious: stop and have it checked.
Compare with: Rough idle with the check engine light on
How to fix
Step 1: With the engine off and cool, check that the EGR valve connector is fully seated.
Step 2: Ask a dealer whether your VIN has a bulletin, software update or warranty extension for P0404.
On your vehicle
HondaYour car
2011–2014 · Odyssey
Supported by vehicle dataHonda A13-095 says the engine computer can damage the EGR valve by commanding too much lift, so a software update goes with the repair. Whether the bulletin is still current is not verified.
A13-095Status unverified
MIL with P0404 EGR valve circuit range/performance
2011–2014odyssey · issued · NHTSA 10099621
Honda says the engine computer may command too much EGR lift after extended driving, damaging the valve internally.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
RamYour car
2012–2013 · 1500
Supported by vehicle dataRam warranty extension X63 replaces the EGR valve when P0404 is set.
09-010-16 Rev. AStatus unverified
Engine surge or hard start, X63 warranty extension
2012–20131500 · issued · NHTSA 10121673
Ram replaces the EGR valve if P0404 (EGR position sensor performance) is set; owners may notice surging and hard starting.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Land RoverYour car
2016–2017 · Range Rover Sport · 3.0 TDV6
Supported by vehicle dataOn the TDV6 diesel, P0404 can bring a restricted performance warning; follow Land Rover SSM73311.
SSM73311Status unverified
MIL and/or restricted performance with P0404
2016–2017range-rover, range-rover-sport · 3.0 TDV6 · issued · NHTSA 10106446
Land Rover addresses P0404 with a restricted performance warning on 3.0 TDV6 diesels.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
P0404 questions
Is it safe to drive with P0404?
Usually, for a while. It is an emissions fault and many cars drive normally. Get it checked soon if the engine surges, stalls, is hard to start or loses power.
Will cleaning the EGR valve fix P0404?
Sometimes. Carbon is the most common cause, but a failed position sensor, a loose connector or a software issue can also set it. Check the connector and any bulletins first.
Sources and review
- The basics of EGRs - what they do, how they work, how to troubleshoot
- 2011–2014 Odyssey: MIL with P0404 EGR valve circuit range/performance (bulletin A13-095)
- Engine surge or hard start, X63 warranty extension: replace EGR valve if P0404 is set (09-010-16 Rev. A)
- 3.0 TDV6: MIL and/or restricted performance warning with P0404-77/84 (SSM73311)
- 2005–2006 Equinox: P0404 or P1404 from a possibly stuck EGR pintle (bulletin 3638)
- MIL due to EGR position sensor DTC P0404, P0405, P0406 (bulletin 18-027-07)
- Repeating EGR DTCs P042E, P0403, P0404, P0409: EGR valve connector terminal spread (SB-10-N-001)
- 6.4L diesel under 5,000 miles: P0404 and/or P1335 from weld slag in the EGR valve (SB-21066)
- 6.0L diesel: MIL with P0401, P0402, P0404, P1335, lack of power or surge (bulletin 07219)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
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