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Severity: Low Code type: Manufacturer-specific (Chevrolet)

Chevrolet P1404 Code: EGR Closed Position Performance

The electric EGR valve on a Chevy isn't fully closing when the PCM commands it shut.

At a glance

Severity: 2/5 – Low2/5

Severity: Low

Meaning
EGR Closed Position Performance
System
Emission Controls · Powertrain
Safe to drive?
Yes, short term
Typical repair cost
$10–$450
DIY difficulty
Easy

Many Chevrolets from roughly the mid-1990s to mid-2000s, including 2.2L four-cylinders, 3.1L/3.4L and 3800 V6 cars and vans, and 4.3L Vortec trucks, use GM's electric linear EGR valve with a built-in pintle position sensor. When the engine first starts, the PCM learns the sensor voltage of the fully closed valve. P1404 sets when the valve is commanded closed but the pintle position reads noticeably above that learned value, in other words, the valve is stuck partly open. Carbon flakes wedged under the pintle are the usual reason, and because exhaust gas then leaks into the intake at idle, the engine can idle rough or stall at stops.

Can I keep driving? It's safe to drive, but expect a rough idle and occasional stalling at stops or when slowing down, which can be a nuisance in traffic. Cleaning or replacing the valve is usually a straightforward job.

How to read P1404

How to read P1404P11243044
  1. P Powertrain
  2. 1 Manufacturer-specific
  3. 4 Auxiliary emission controls
  4. 04 Specific fault

Symptoms

  • Check engine light on
  • Rough, shaky idle that smooths out above idle
  • Stalling when coming to a stop or pulling into a parking space
  • Hesitation just off idle
  • Occasional misfire codes at idle

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Carbon deposits under the EGR pintle holding the valve slightly open 45%
  2. Worn EGR valve or failed internal pintle position sensor 25%
  3. Carbon-packed EGR seat or passage in the intake preventing full closure 12%
  4. Wiring or connector fault on the 5 V reference, signal or ground of the position sensor 10%
  5. Incorrect closed-position learn after a valve replacement or battery disconnect 8%

Diagnosis step by step

Diagnostic flow: P14041Compare desired and actual EGRposition2Command the valve open and closed3Check the position sensor voltage4Remove and inspect the valve5Clean the valve and passage6Relearn and verify

  1. Compare desired and actual EGR position

    With a scan tool, look at desired EGR position and actual pintle position at warm idle. Desired should be 0 %; if actual reads above a few percent while commanded closed, the valve isn't seating.

    Tools: OBD-II scanner

  2. Command the valve open and closed

    Use the scan tool's EGR control to step the valve to 25, 50 and 75 % and back to 0 %. The actual position should follow smoothly and return fully; hesitation or sticking on the way back confirms a mechanical problem.

    Tools: OBD-II scanner

  3. Check the position sensor voltage

    Back-probe the signal wire: a closed valve typically sits well under 1 V and the reading rises smoothly toward about 4.5 V as it opens. Also confirm a steady 5 V reference and a good ground at the connector.

    Tools: Multimeter

  4. Remove and inspect the valve

    Take off the EGR valve (usually two or three bolts) and look at the pintle and seat. Hard carbon flakes caught under the pintle or crusted around the seat are the typical finding.

    Tools: Screwdriver, Flashlight

  5. Clean the valve and passage

    Scrape and spray the carbon from the pintle, seat and the intake port with a carbon or throttle body cleaner, without soaking the electrical part of the valve. Refit with a new gasket.

    Tools: Soft brush, Gloves

  6. Relearn and verify

    Clear the codes and cycle the ignition so the PCM relearns the closed position, then idle and drive. If P1404 returns with a clean valve, replace the EGR valve assembly.

    Tools: OBD-II scanner

Where the parts are

Air intake and fuel metering – P140412345678
Air intake and fuel metering
  1. 1MAF sensor
  2. 2Turbocharger
  3. 3Throttle body
  4. 4Intake manifold
  5. 5Fuel injector
  6. 6EGR valve
  7. 7Fuel pump
  8. 8Thermostat

Repair options & costs

RepairDIY?Estimated cost
Clean EGR valve and port Yes $10–$150
Replace EGR valve (DIY) Yes $90–$250
Replace EGR valve (shop) No $200–$450
Repair EGR sensor wiring or connector No $80–$220

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Emissions / smog test impact

Will fail

With P1404 stored the check engine light is lit, so the vehicle fails a US OBD emissions test until the EGR valve is fixed and the EGR monitor has run again.

Frequently asked questions

Can I just clean the EGR valve?

Often yes. If the pintle is simply held open by carbon, cleaning the valve and its port fixes P1404. If the position sensor inside the valve is worn, only a new valve helps.

Why does my Chevy stall at stoplights with P1404?

A valve that stays open lets exhaust gas into the intake at idle, which dilutes the mixture. At higher rpm the engine tolerates it, but at idle it can run rough or stall.

What's the difference between P1404 and P0404?

P0404 is the generic EGR position range/performance code. P1404 is GM's more specific version: it flags that the valve isn't closing fully when commanded shut.

Do I need to relearn the EGR valve after replacing it?

The PCM learns the closed position by itself at key-on. Clear the codes after the repair and let the engine idle so the new value is stored.

Sources