P1406 Code: Meaning, Symptoms, Causes & Fix

Overview

Symptoms

• rough idle under load
• failed emissions test readiness
• increased fuel consumption

Common causes

• Mechanical restriction affecting response affecting exhaust gas recirculation (egr) position sensor performance
• Sensor drift or delayed actuation
• Connector pin damage/corrosion or harness stress near related components

How to diagnose P1406

1. Confirm P1406 and capture freeze-frame data with a professional scan tool.
2. Inspect wiring, connectors, and grounds related to exhaust gas recirculation (egr) position sensor performance for obvious defects.
3. Compare commanded vs actual values in live data under the same operating condition.
4. Check for related DTCs to identify the root-cause chain before replacing parts.
5. After repair, clear codes and confirm readiness monitors complete without recurrence.

Severity of code P1406

Moderate: This code is moderate severity: the vehicle may still operate, but fault progression can increase repair cost over time.

Can you drive with P1406?

Most vehicles can be driven short-term with P1406, but postpone heavy load/highway driving until repaired.

If the warning lamp is flashing or drivability/safety is affected, avoid driving and diagnose immediately.

How to fix it (step-by-step)

1. Repair obvious wiring/connector faults first to prevent repeat parts replacement.
2. Address the root fault mode (performance) in the exhaust gas recirculation (egr) position sensor performance circuit/system.
3. Apply the required relearn/adaptation procedure if specified by service information.
4. Road-test and verify P1406 remains cleared under the conditions that originally set the code.

Fix options

• Test component operation against service specs.
• Clean/repair mechanical restriction where applicable.
• Clear DTCs and verify with live data and completed drive cycle.

Typical repair cost

$180-$900

Common mistakes when diagnosing P1406

• Replacing parts without verifying voltage, ground, and signal integrity first.
• Ignoring related stored/pending codes that indicate upstream faults.
• Skipping post-repair verification drive cycle and readiness checks.

P1406 in common vehicles

P1406 appears across makes such as Ford, Toyota, Honda, Chevrolet. Failure patterns differ by platform: wiring routes, software calibration, and component supplier revisions can change root cause.

Frequently asked questions

What causes P1406?

P1406 is commonly set by performance faults affecting exhaust gas recirculation (egr) position sensor performance.

How much does it cost to fix P1406?

For P1406, repair costs are typically $180-$900 depending on exact root cause, labor rates, and part quality.

Can I clear P1406 without repair?

You can clear P1406 temporarily, but the code usually returns until the underlying fault is corrected.

Helpful tools

• Estimate repair cost
• Decode your VIN
• Calculate fuel cost