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

Ford P1405 Code: DPFE Sensor Upstream Hose Off or Plugged

Ford's EGR flow sensor isn't getting exhaust pressure on its upstream port: loose, split or clogged hose.

At a glance

Severity: 2/5 – Low2/5

Severity: Low

Meaning
DPFE Sensor Upstream Hose Off or Plugged
System
Emission Controls · Powertrain
Safe to drive?
Yes, short term
Typical repair cost
$0–$400
DIY difficulty
Easy

Ford measures EGR flow with a DPFE (Delta Pressure Feedback EGR) sensor that reads the pressure difference across a small calibrated orifice inside the metal EGR tube. Two short rubber hoses connect the sensor to that tube: the upstream hose taps exhaust pressure on the exhaust-manifold side of the orifice, and the downstream hose taps the EGR-valve side. P1405 sets when the PCM's plausibility check shows that the upstream side isn't seeing exhaust pressure, typically because the sensor signal sits below its own engine-off baseline when it should be at or above it. The code is common on EEC-V era US-market Fords such as the 3.0 Vulcan Taurus and Ranger, Windstar, Explorer 4.0 and the 4.6/5.4 trucks, where the hoses bake hard over the exhaust and split at the ends.

Can I keep driving? Safe to drive for now. With EGR feedback wrong, the PCM may meter EGR poorly, which can bring on spark knock under load and higher NOx, so avoid lugging the engine and fix it before an emissions test.

Try this first – 5-minute fix

  1. Look at the two hoses With the engine cool, find the DPFE sensor near the EGR valve and follow its two hoses to the metal EGR tube. A split end, a hose hanging loose or a hardened hose that crumbles when squeezed is very often the whole problem.
  2. Replace both hoses with the right material Use high-temperature silicone or Ford-spec DPFE hose, not ordinary vacuum line, and replace both while you're there. Route them so neither sags into a low loop where water can collect.
  3. Check port orientation, clear and drive The port marked HI (or the one that faces the exhaust) must go to the tube port nearest the exhaust manifold. Clear the code and drive a mixed city and highway loop so the EGR monitor can run again.

How to read P1405

How to read P1405P11243054
  1. P Powertrain
  2. 1 Manufacturer-specific
  3. 4 Auxiliary emission controls
  4. 05 Specific fault

Symptoms

  • Check engine light on, usually with no change in how the engine runs
  • Light pinging or spark knock when accelerating uphill or towing
  • P0401 (insufficient EGR flow) may be stored at the same time or shortly after
  • Visible cracked or disconnected rubber hose at the DPFE sensor
  • Failed emissions test for high NOx on states that still do a tailpipe test

Possible causes

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

  1. Upstream DPFE hose cracked, split at the end, or slipped off the metal EGR tube nipple 35%
  2. Upstream hose plugged with soot, or blocked by water that condensed in a sagging loop and froze 20%
  3. Hoses swapped between the two sensor ports after a sensor or hose replacement 15%
  4. Upstream pickup port on the metal EGR tube packed with carbon 15%
  5. DPFE sensor with a failed internal diaphragm or port 10%
  6. Poorly calibrated aftermarket DPFE sensor 5%

Diagnosis step by step

Diagnostic flow: P14051Map the hose layout on your engine2Check hose condition and flow3Clear the tube port4Read the baseline voltage5Bench-test the sensor with a vacuumpump6Verify the repair

  1. Map the hose layout on your engine

    Identify which tube nipple is upstream (closest to the exhaust manifold, before the orifice) and which is downstream (next to the EGR valve). Many DPFE sensors mark the ports HI and REF; on a lot of Fords the two hoses also have different inside diameters, which helps you catch a swapped installation.

    Tools: Flashlight

  2. Check hose condition and flow

    Pull the upstream hose off both ends, bend it, and blow through it. It must be soft, crack-free and open; any soot plug, water or ice means replacement and a better route.

    Tools: Pliers

  3. Clear the tube port

    Carbon often closes the small upstream port on the EGR tube itself. With the engine cold, carefully clear it by hand with a small drill bit or pick; don't let debris fall into the tube and don't enlarge the hole.

    Tools: Flashlight

  4. Read the baseline voltage

    Key on, engine off, read the DPFE signal PID or back-probe the signal wire. Aluminum-bodied sensors typically sit near 0.9 to 1.1 V, older ceramic ones near 0.45 V. At warm idle with EGR commanded off it should stay close to that baseline; a signal that drops below the key-on value points at the upstream side.

    Tools: OBD-II scanner, Multimeter

  5. Bench-test the sensor with a vacuum pump

    With the key on and the hoses off, apply vacuum to the downstream (REF) port with a hand pump. The signal should rise smoothly as vacuum increases, toward about 4 V; a dead, jumpy or stuck reading condemns the sensor.

    Tools: Vacuum gauge, Multimeter

  6. Verify the repair

    Clear codes, then drive at steady highway speed with light acceleration so the EGR monitor runs. Recheck for P1405, P1406 and P0401 before going for an emissions test.

    Tools: OBD-II scanner

Where the parts are

Air intake and fuel metering – P140512345678
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
Replace both DPFE hoses (high-temp hose) Yes $15–$90
Clean carbon from EGR tube pickup ports Yes $0–$120
Replace DPFE sensor (quality or Motorcraft unit) Yes $90–$260
Replace corroded EGR tube with orifice No $150–$400
Shop EGR system diagnosis No $100–$180

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

Emissions / smog test impact

Will fail

P1405 turns on the check engine light, so the vehicle fails a US OBD emissions test. After the hose or sensor repair, the EGR monitor has to show ready again before retesting.

Frequently asked questions

Can I just use regular vacuum hose on the DPFE?

Not for long. These hoses carry hot exhaust pressure and sit close to the manifold, so ordinary vacuum hose hardens and cracks quickly and the code comes back. Use high-temperature silicone or the correct Ford DPFE hose.

Will a new DPFE sensor fix P1405?

Only if the sensor is actually bad. Most P1405 cases are hose or port problems; a new sensor installed with the old cracked hoses, or with the hoses swapped, will set the same code again.

What's the difference between P1405 and P1406?

P1405 is the upstream hose, which carries pressure from the exhaust side of the orifice. P1406 is the downstream hose on the EGR-valve side. The symptoms are similar, but the signal moves in opposite directions, which is how the PCM tells them apart.

Why does this code show up in winter?

Exhaust contains water vapor that condenses in the hoses. If a hose sags into a loop, water collects there and can freeze solid on cold mornings, blocking the pressure signal until it thaws.

Sources