P1405 Explained: DPF EGR Sensor Circuit High Voltage Detected

"I have a 2000 Lincoln LS V8. A few days ago, the check engine light suddenly came on. I checked it with a code reader, and it displayed error code P1405. I can't find any helpful information online, and I just want to get it fixed quickly to prevent further damage. If anyone could explain this error code, I'd be grateful."

If this sounds familiar, you've come to the right place. The sudden illumination of the check engine light with the P1405 code often confuses car owners, but understanding it can help you resolve the issue quickly and avoid more serious problems later. Read on to learn about its causes, symptoms, solutions, and more.

What Does the Ford Code P1405 Mean?

P1405 stands for "DPF EGR Sensor Circuit High Voltage Detected". Simply put, it means your vehicle's computer has detected a problem with the EGR (exhaust gas recirculation) system - specifically, the circuit that monitors EGR flow using the DPFE sensor. The P1405 fault is triggered when the powertrain control module (PCM) detects an abnormally high voltage at this sensor.

Common Symptoms of the P1405 Code

You may experience one or more of the following:

• The Check Engine Light remains on.
• Rough or hesitant idling: The engine may stall when stopped.
• Acceleration problems: Hesitation or stalling when pressing the accelerator.
• Degraded fuel economy: More frequent trips to the gas station.
• Emissions test failure: Failed smog check.
• Related Codes: May also appear with codes such as P0401 ("Insufficient EGR Flow") or P0402 ("Excessive EGR Flow").

No obvious symptoms: Sometimes, especially early on, the only sign is the Check Engine Light. Identifying these symptoms early can make diagnosis and repair easier and less expensive.

What Causes Code P1405?

The most common triggers for P1405 are:

• Disconnected or clogged DPFE sensor hose: EGR gases can cause carbon deposits, which can clog the hose connected to the DPFE sensor.
• DPFE sensor malfunction: Prolonged exposure to exhaust manifold heat can cause internal sensor failure.
• Corroded or broken wires/connectors: After years of vibration and heat, wires and connectors can corrode, break, or lose contact.
• Carbon deposits in the EGR passage: Carbon deposits in the EGR passage can cause blockages, distorting the readings.
• Nearby leaks: Any vacuum leak near the EGR system can affect the sensor readings.
• Rare: PCM malfunction. In rare cases, the PCM (vehicle computer) can malfunction and misinterpret the sensor data.

How to Fix P1405 Code (Step-by-Step Instructions)

You can use this DIY checklist to fix the P1405 Ford code, or consult a mechanic for more complex issues.

Step 1: Inspect the DPFE Sensor Hose

Inspect for damage or detachment: Check for cracked, split, or loose hoses.

Clean or replace: If the hose is clogged with carbon, clean or replace it with compressed air.

Step 2: Test or Replace the DPFE Sensor

Visual inspection: Inspect the DPFE sensor for melted or deformed plastic.

Test voltage: If the hose is fine, use a multimeter to check the sensor itself. With the key on/engine off, the reference voltage should be between 0.45 and 0.55 volts. If the reading is too high, replace the sensor.

Step 3: Clean the EGR Passage

Remove carbon deposits: Use EGR cleaner and a brush to remove carbon deposits from the EGR valve and its passages (paying special attention to the intake manifold port).

Step 4: Check the Wiring and Connectors

Look for corrosion: Clean the contacts and replace any damaged wires.

Check for pinched or cut wires: These can cause intermittent sensor readings.

Step 5: Clear the Code and Retest

Clear the code: Use an OBD-II scanner after the repair, then test drive the car to see if the code returns.

Tip: After completing each step, use an OBD-II scanner to check if the error recurs. This will help narrow down the cause of the error.

Want a Permanent Fix? Consider an EGR Delete Kit

If your vehicle repeatedly experiences EGR-related errors (such as P1405) despite replacing sensors, hoses, or cleaning them, you may want to consider installing an EGR delete kit. This is especially true if your vehicle is used off-road or for show and doesn't need to pass emissions testing.

✅ Benefits of EGR Delete

• Permanently eliminates EGR-related codes like P1405, P0401, and P0402;
• Simplifies engine system and reduces maintenance costs;
• Improves airflow, throttle response, and potentially increases fuel efficiency.

⚠️ Legal Disclaimer

In most jurisdictions, EGR delete kits are only suitable for off-road use. Removing emissions equipment may violate local or federal laws. Always check local regulations before proceeding.

🛒 Recommended EGR Delete Kits

We offer high-quality EGR delete kits compatible with Ford engines.

👉 [Click here to browse our EGR delete kits and exclusive discounts.]

Estimated Repair Costs for a P1405 Code

Here are some common repairs and their prices:

A DIY repair may significantly reduce these costs.

FAQs

Can I still drive a vehicle with a P1405 fault?

Yes, but only temporarily. Long-term driving may increase emissions, reduce fuel efficiency, and trigger more fault codes. It's best to diagnose and resolve the problem quickly.

Which models are most affected by Ford code P1405?

P1405 is most commonly found in:

• Ford F-150
• Ford Ranger
• Ford Expedition
• Ford Explorer
• Ford Taurus (certain years)

It can also affect Mercury and Lincoln models equipped with similar EGR systems.

Why is my P1405 error recurring?

• Damaged wiring: Especially above the sensor harness.
• Improperly cleaned EGR port: Hidden carbon deposits may cause the problem to recur.
• PCM flash required: Some models may require a software update.

What is the relationship between P1405 and P0401?

P1405: Indicates a problem with the DPFE sensor circuit.

P0401 stands for "Insufficient EGR Flow" and is typically caused by a faulty DPFE sensor or a clogged EGR passage. Fixing P1405 code often resolves P0401.

Do P1405 and P0401 always occur together?

Not always, but in approximately 70% of cases, a faulty DPFE sensor triggers both fault codes. Fix P1405 first.

Are aftermarket DPFE sensors reliable?

No, you need to avoid cheap, off-brand sensors.

Conclusion

The P1405 Ford code may be confusing at first, but it's completely fixable with a structured approach. P1405 is associated with a high voltage reading in the DPFE sensor circuit and is often caused by a disconnected hose, a faulty sensor, or EGR deposits. Before considering a PCM issue, start with a low-cost inspection (hoses, sensors, wiring). For recurring issues, an EGR removal kit may provide a long-term solution (if legal).