Chrysler Fault Code P1405: Complete Diagnosis and Solutions

The illuminated check engine light on your Chrysler dashboard is always a cause for concern. When the scanner reveals fault code P1405 Chrysler, it indicates a specific problem with the Exhaust Gas Recirculation (EGR) system. Unlike other generic codes, P1405 is often a manufacturer-specific code, making it particularly relevant for owners of Chrysler, Dodge, and Jeep vehicles. This detailed guide explains everything you need to know about this fault: its origin, symptoms, diagnostic methods, and most importantly, how to fix it to restore optimal performance.

What is Code P1405 on a Chrysler?

The fault code P1405 is stored by the Powertrain Control Module (PCM) when it detects a problem with the circuit or performance of the EGR system’s Differential Pressure Feedback EGR (DPFE) sensor. This crucial sensor’s job is to measure the difference in exhaust gas pressure between the two sides of the EGR system’s metering orifice. This data allows the PCM to verify that the EGR valve is opening correctly and that the flow of recirculated gases matches the expected values. An incorrect or missing signal from this sensor immediately triggers the P1405 code and illuminates the malfunction indicator lamp.

Symptoms of Fault P1405

It is rare for a vehicle to have the P1405 code without any noticeable symptoms. The most common signs include:

• Illuminated Check Engine Light: The most obvious indication.
• Irregular or Rough Idle
• Loss of Power and Poor Acceleration, especially under load.
• Increased Fuel Consumption.
• In some cases, the vehicle may enter Limp Mode to protect the engine.
• Engine Misfires may sometimes occur.

Probable Causes of Chrysler Code P1405

Several components can be the source of this fault. A methodical diagnosis is essential to avoid replacing parts unnecessarily.

• Faulty DPFE Sensor: The most common cause. The sensor itself is faulty and sends inconsistent values to the PCM.
• Clogged or Damaged DPFE Sensor Hoses: The small rubber hoses connecting the sensor to the EGR system can become clogged with soot, crack, or come loose.
• Wiring Problems: A faulty electrical circuit, including broken wires, corroded connectors, or poor contacts, can interrupt communication with the sensor.
• Faulty EGR Valve: Although the code points to the sensor, a stuck or clogged EGR valve can skew the pressure readings.
• Clogged EGR Metering Orifice: The orifice that creates the pressure difference measured by the sensor can be blocked.

Diagnosis and Repair Procedure

Before replacing the sensor, follow these steps to identify the root cause of the Chrysler P1405 problem.

1. Visual Inspection

Start with a thorough visual inspection. Locate the DPFE sensor (usually mounted on the intake manifold or near the EGR valve). Check the condition of the two small rubber hoses connected to it. Make sure they are not punctured, crushed, disconnected, or clogged. Inspect the electrical connector for any signs of corrosion or damage.

2. Testing the Hoses and Orifice

Carefully disconnect the hoses from the sensor and blow through them to check for blockages. Use an appropriate tool to check that the metering orifice in the EGR valve body is not clogged with carbon deposits.

3. Electrical Test of the DPFE Sensor

Using a multimeter, measure the sensor’s supply voltage (5V reference) and ground. With the ignition on but the engine off, probe the signal wire. The voltage should typically be around 0.4-0.6V. At idle, this voltage should increase (e.g., to 1.5-2.0V) when the EGR valve is activated. A value that does not change or is out of specification indicates a faulty sensor.

4. Cleaning or Replacement

If the hoses and wiring are in good condition, the DPFE sensor is most likely the cause. Replacement is often the most effective solution. Remember to clear the code with an OBD2 scanner after the repair to turn off the check engine light and verify that the fault does not return.

Conclusion

Although the Chrysler fault code P1405 may seem technical, it is often resolved with a simple diagnostic procedure. By starting with a visual inspection of the most accessible components (hoses, connectors), you can often identify and fix the problem without a major investment. If the DPFE sensor itself is at fault, its replacement is an affordable operation that will restore your engine’s performance and extinguish that annoying check engine light.