P1405 — DPFE Circuit Low Input

P1405 — DPFE Circuit Low Input. A fault in the sensor and actuator circuits. The car is usually drivable while you plan the repair. Typical causes: faulty sensor or actuator of the affected circuit, open or shorted wiring in the circuit, control module driver fault.

For Ford vehicles

differential pressure feedback sensor upstream hose off or plugged

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P1405 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the DPFE for damage, corrosion, chafing or poor contact.
Subsystem check Check for supply voltage at the DPFE connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P1405 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P1405 (parts and labor, USD, independent shop rates): Repair wiring or connectors: $80–$250; Replace the faulty sensor or actuator: $150–$500; Control module repair: $300–$1,000. Overall, fixing P1405 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How much does it cost to fix P1405?

Repair wiring or connectors — $80–$250; Replace the faulty sensor or actuator — $150–$500; Control module repair — $300–$1,000. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

Is it safe to drive with P1405?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How do I diagnose P1405 myself?

Start with a scan: confirm P1405, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the DPFE, and verify the suspect component against live data before buying parts.

What does OBD2 code P1405 mean?

What are the symptoms of P1405?

Drivers most often notice: Check Engine Light on, increased fuel consumption in some cases, possible limp mode depending on the affected component, the affected system operates intermittently or not at all.

When your scan tool pulls a P1405, the engine computer has detected that a specific circuit is running at a voltage level far below where it should be. This particular code falls under the powertrain category and carries the technical label "DPFE Circuit Low Input." The DPFE sensor—short for Differential Pressure Feedback EGR—monitors exhaust gas recirculation system performance, and when its electrical circuit drops toward ground potential, the control module logs this fault.

The "circuit low" designation tells you the problem lives in the wiring or the component itself pulling the signal down. Several scenarios can cause this: a wire with damaged insulation might be shorted to the chassis ground, a connector could be corroded or pushed in partially, the sensor might have failed internally, or power supply to the DPFE could be interrupted. The ECU sets P1405 when sensor readings stay outside the acceptable voltage window over multiple drive cycles, storing a freeze frame snapshot along with it that captures RPM, engine load, coolant temperature, and vehicle speed at the moment of failure.

That freeze frame data matters because it lets you recreate the exact conditions under which the fault appeared. If you duplicate those conditions during testing, you can often trigger the failure consistently and verify your fix actually resolved the underlying issue.

Symptoms of P1405

Check Engine Light illuminates and stays on
Fuel economy drops noticeably in some vehicles
Transmission may shift into limp mode, limiting gears
The EGR system stops working or operates erratically
Engine runs roughly or idles unstable when the fault is active
In rare cases, reduced boost pressure on turbocharged engines

Common Causes of P1405

Internal failure of the DPFE sensor drawing the circuit low
Signal wire grounding out due to chafed insulation or pinched wiring
Broken or corroded connector terminals preventing proper contact
Loss of reference voltage supply to the DPFE circuit
Weak or oxidized ground connection at the sensor
Wiring harness damage from road debris or engine heat
Failed upstream sensor or actuator dragging the shared circuit down

How to Diagnose P1405

Connect your OBD2 scanner, confirm P1405 is stored, and record the freeze frame data—this snapshot tells you engine conditions when the fault triggered.
Look for any related trouble codes. P1406 (DPFE Circuit High Input) often appears alongside P1405 and can point you toward whether the problem is a short, open circuit, or failed component. Check manufacturer TSB databases for known fixes specific to your vehicle.
Inspect the DPFE wiring harness visually. Look for cracked insulation, burned spots, wires rubbing against metal brackets, and any signs of moisture intrusion at connectors. A flashlight and mirror help reach tight spots.
Test for a short to ground at the connector. Back-probe the signal circuit and check resistance to chassis ground with the sensor unplugged—continuity or very low ohms confirms a wiring short.
Verify proper voltage supply and ground at the sensor connector. The DPFE needs 5-volt reference, signal return, and good ground to function correctly. Any missing element explains the low reading.
Perform a wiggle test on the harness while monitoring live data. If the signal drops out when you move certain wires, you've found an intermittent break or poor connection.
Clear the code and complete a drive cycle matching the freeze frame conditions. If P1405 returns, the repair isn't complete.

Repair Options for P1405

Wiring repair or connector replacement: $80–$250. Most cost-effective approach when you find damaged wires or corroded terminals. Use proper weatherproof connectors and dielectric grease to prevent future issues.
DPFE sensor replacement: $150–$500. If the sensor itself has failed internally, replacement restores proper EGR flow monitoring. Some manufacturers require a related solenoid or bracket assembly that pushes the price higher.
Control module diagnosis or repair: $300–$1,000. Rarely the culprit, but if all wiring and sensors check out and the fault persists, the PCM may need reflashing or replacement.

Total Repair Cost for P1405

Your actual spend hinges entirely on which component triggered the fault. Independent shop labor typically runs $75–$125 per hour. Wiring repairs usually take under two hours, sensor replacement one to two hours, and module work three to four hours when necessary. Parts pricing varies by manufacturer—aftermarket DPFE sensors range $40–$120 while OEM units run $150–$300. Expect to pay between $80 and $1,000 total depending on root cause. Always pursue accurate diagnosis before purchasing expensive modules—you'll eliminate the cheap fix as a possibility, but you won't waste money guessing wrong on a $600 computer.

Can You Drive with P1405?

Most vehicles remain drivable when this code is active, though you may notice sluggish acceleration, poor throttle response, or an illuminated limiter light. The EGR system typically disables itself as a failsafe, which doesn't create an immediate safety hazard. That said, prolonged operation with unresolved emissions faults can allow unburned hydrocarbons to damage catalytic converters downstream. If your vehicle exhibits stalling, hard starting, or warning lights beyond the Check Engine indicator, treat it as urgent and address it promptly.