P1406 Code: EGR Valve Pintle Position Circuit (GM)

What the P1406 code means

P1406 is a manufacturer-specific code: the 1 in the second position means each automaker defines what it means, not the generic SAE standard. That is why the same number means different things depending on the vehicle, as the table shows. This page focuses on the General Motors meaning (Chevrolet, GMC, Buick, Cadillac).

Electric EGR valves on GM vehicles have a sensor that measures the position of the valve pintle to confirm how far it opened.

The computer sets the P1406 code when the pintle position does not match the command or the sensor signal is out of range. Carbon that jams the pintle is the usual cause.

Before you start repairs, confirm the make, model, year and engine. With manufacturer codes, the same number can change even between engines from the same brand.

P1406 code symptoms

• Check engine light on.
• Rough idle if the valve sticks open.
• Hesitation and jerking.

Likely causes of the P1406 code

1. Carbon buildup on the valve. Check it by commanding the valve with the scan tool.
2. Valve position sensor. Confirm it by comparing its reading with the real value.
3. Connector or wiring. Check the lock tab, the pins and any sign of moisture or corrosion.
4. Failed valve. Check it by commanding the valve with the scan tool.

How to diagnose the P1406 code step by step

1. Compare the commanded and actual position on the scan tool.
2. Clean the valve and check that the pintle moves freely.
3. Measure the 5 V reference at the sensor connector.

How to fix the P1406 code

• Clean or replace the EGR valve.
• Repair the wiring.

Technical reference data

• Position signal: roughly 0.5 to 1 V with the valve closed.
• P1xxx codes are manufacturer-specific: confirm the definition with a scan tool that supports your brand.
• Reference values: check the manufacturer data for your vehicle.

Brand-specific notes

On GM vehicles this code is mostly about carbon on the valve, so cleaning comes before replacing.

P1406 on GM

Common on the Chevrolet, Buick, Pontiac and Oldsmobile with the 3.1 and 3.4 V6 engines.

P1406 on Ford

Ford uses the same number for a different fault: the DPFE sensor outlet hose is disconnected or plugged.

If your vehicle is another brand, check the table above for the meaning its manufacturer gives this code and confirm it with a compatible scan tool.

Frequently asked questions about P1406