P04DB The computer believes the crankcase ventilation system has come apart, so crankcase pressure is not behaving as it should

Crankcase ventilation system disconnected

Monitor

The Ford bulletins describe an illuminated check engine light as the complaint and do not describe drivability problems, so you can usually drive while you book a check.

Source: how we rate severity

P04DB in short

P04DB means the computer thinks the crankcase ventilation system has come disconnected. On Ford EcoBoost engines the finds are a partly disconnected crankcase pressure sensor tube, or a software issue that Ford fixes with an update. It usually just lights the check engine light. Have the connection checked.

The crankcase ventilation system routes fumes from the engine back into the intake. On turbocharged engines a sensor watches the pressure in that path, so the computer can tell if a hose has come off or the line has opened.

Ford has issued many bulletins for P04DB on 1.0L, 1.5L, 2.0L and 2.3L turbo engines from 2016 to 2018, built before certain dates. The 2018 Escape bulletin says to inspect the crankcase pressure sensor tube at the rear air intake for a partial disconnect and to check the quick-release coupling O-ring. The 2.3L Explorer bulletin says to reprogram the computer.

Ford noted for the 2018 Escape that engineering was still investigating, so the cause and fix on some vehicles may change.

Most likely causes

  1. Partly disconnected crankcase pressure sensor tube or damaged O-ring

    Supported by vehicle data
    Why it ranks here
    Ford SSM 47238 tells technicians to inspect the crankcase pressure sensor tube at the rear air intake for a partial disconnect and to inspect the quick-release coupling O-ring for damage on 2018 Escape with the 1.5L engine.
    What would change this
    Rises if the tube is not fully seated or the O-ring is damaged. Falls if the tube is tight and the O-ring is good.
    How to test the crankcase ventilation (pcv) valve

  2. Engine computer software (2.3L EcoBoost Explorer)

    Supported by vehicle data
    Why it ranks here
    Ford TSB 18-2007 says to reprogram the computer on 2017-2018 Explorers with the 2.3L EcoBoost built on or before 7 December 2017 that set P04DB.
    What would change this
    Rises on these Explorers if the computer is not at the latest calibration. Falls if it is current.
    How to test the engine control module (ecm / pcm)

  3. A disconnected or damaged crankcase vent hose

    Common general cause
    Why it ranks here
    The code name itself says disconnected; TroubleCodes.net gives "crankcase ventilation system disconnected" as the probable cause. Ford bulletins for the other engines say to follow the service procedure without describing it.
    What would change this
    Rises if a hose is loose, cracked or off. Falls if every hose is attached and intact.
    How to test the crankcase ventilation (pcv) valve

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Ask a dealer whether your VIN is covered by a Ford bulletin for P04DB. Ford has issued bulletins for 2016-2018 Fiesta, Focus, Escape, MKC, Edge, Fusion, MKZ and Explorer.

    Low risk

    • IfA bulletin applies

      It meansFollow its procedure; some call for a computer reprogram and some for a connection check.

      Go to step 2

    • IfNo bulletin applies

      It meansInspect the crankcase vent hoses and sensor tube.

      Go to step 2

  2. With the engine off and cool, check the crankcase vent hoses and the crankcase pressure sensor tube are fully attached, and the quick-release coupling O-ring is intact.

    Use caution

    Warning:The turbo intake can hold hot parts and moving belts. Work only on a cold, stopped engine.

Symptoms

  • Check engine light with no change in how the car drives

How to fix

  1. With the engine off and cool, check that the crankcase vent hoses are fully pushed onto their fittings.

  2. Ask a dealer whether your VIN has an open Ford bulletin for P04DB.

Parts and cost context

  • Crankcase ventilation (PCV) valve:Hoses and O-rings are small parts; a bulletin may call for a software update instead. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

  • 2017–2018 · Escape

    Supported by vehicle data

    Ford issued several bulletins for P04DB on the Escape: 2017-2018 2.0L GTDI (follow the service procedure) and 2018 1.5L EcoBoost (inspect the crankcase pressure sensor tube and coupling O-ring). Whether they are still current is not verified.

  • 2017–2018 · Explorer · 2.3L EcoBoost

    Supported by vehicle data

    Ford TSB 18-2007 says to reprogram the powertrain computer for P04DB on 2.3L EcoBoost Explorers built on or before 7 December 2017. Whether it is still current is not verified.

  • 2017–2018 · Fusion · 2.0L GTDI

    Supported by vehicle data

    Ford TSB 16-0120 and TSB 17-2220 cover P04DB on 2.0L GTDI Fusions built before certain 2016 and 2017 dates. The summaries do not describe the procedure. Whether they are still current is not verified.

  • 2016–2017 · Focus · 1.0L GTDI

    Supported by vehicle data

    Ford TSB 17-0010 and SSM 46705 cover P04DB on 1.0L turbo Focus models. Whether they are still current is not verified.

  • TSB 17-0003Status unverified

    MIL with P04DB (1.0L GTDI)

    2016–2017fiesta · NHTSA 10095122

    Follow the service procedure; the NHTSA summary does not describe it. Covers vehicles built on or before 6 January 2017.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 17-0010Status unverified

    MIL with P04DB (1.0L GTDI)

    2016–2017focus · NHTSA 10095144

    Follow the service procedure; the NHTSA summary does not describe it.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 16-0114Status unverified

    MIL with P04DB (2.0L GTDI)

    2017escape · NHTSA 10109032

    Follow the service procedure; the summary does not describe it. The summary also covers the Lincoln MKC.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 16-0120Status unverified

    MIL with P04DB (2.0L GTDI)

    2017fusion · NHTSA 10109038

    Follow the service procedure; the summary does not describe it. The summary also covers the Lincoln MKZ.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB 17-0066Status unverified

    MIL with P04DB (2.0L GTDI)

    2017–2018escape · NHTSA 10119659

    Follow the service procedure; the summary does not describe it. The summary also covers the Lincoln MKC.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • tsb17-2214Status unverified

    MIL with P04DB (2.0L GTDI)

    2017edge · NHTSA 10125069

    Follow the service procedure; the summary does not describe it.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 17-2220Status unverified

    MIL with P04DB (2.0L GTDI)

    2017–2018fusion · NHTSA 10127395

    Follow the service procedure; the summary does not describe it. The summary also covers the Lincoln MKZ.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • SSM 47238Status unverified

    MIL with P04DB (1.5L EcoBoost)

    2018escape · NHTSA 10137135

    Inspect the crankcase pressure sensor tube at the rear air intake connection for a partial disconnect and the O-ring on the quick-release coupling for damage. Ford said engineering was investigating.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • TSB18-2007Status unverified

    MIL with P04DB (2.3L EcoBoost)

    2017–2018explorer · NHTSA 10138486

    Reprogram the powertrain computer with IDS or FJDS release 108.02 or higher on vehicles built on or before 7 December 2017.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

No curated relationships for P04DB yet.

All Fuel trim (air-fuel mixture) codes

P04DB questions

Is it safe to drive with P04DB?

Usually yes. The Ford bulletins describe a lit check engine light and no drivability problem. Have a dealer check the crankcase sensor tube and hoses.

Sources and review

  1. TSB 18-2007 MIL with P04DB, 2017-2018 Explorer 2.3L EcoBoost — Ford Motor Company
  2. SSM 47238 MIL with P04DB, 2018 Escape 1.5L EcoBoost — Ford Motor Company
  3. P04DB trouble code summary — TroubleCodes.net
  4. TSB 16-0114 MIL with P04DB, 2017 Escape and MKC 2.0L GTDI — Ford Motor Company
  5. TSB 17-2220 MIL with P04DB, 2017-2018 Fusion and MKZ 2.0L GTDI — Ford Motor Company
  6. SSM 46705 MIL with P04DB, 2017 Focus 1.0L — Ford Motor Company
Last reviewed
Written by
Saurabh K.
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