What does P1418 mean on a Chevy?

P1418. Secondary Air Injection System Relay A Control Circuit High. Applies to Silverado, Sierra, Tahoe, Yukon, Corvette.

What causes P1418 on a Chevy?

Failed AIR pump relay with welded contacts in the underhood fuse block Short to voltage on the relay control circuit from the PCM Corroded relay socket terminals in the underhood electrical center Faulty PCM driver holding the relay control circuit high

How do I fix P1418 on a Chevy?

Swap the AIR relay with a known-good identical relay and retest before buying parts Test the relay control circuit for a short to voltage with a multimeter Inspect the underhood fuse block for green corrosion on the relay pins Verify PCM command with a Tech2/GDS2 scan tool before condemning the module

Code

P1418

Secondary Air Injection System Relay A Control Circuit High

Category: Powertrain - Auxiliary Emissions Controls
Severity: Check Engine Light
Applies to: Silverado, Sierra, Tahoe, Yukon, Corvette
Related: No single generic twin. See OBD Codes List

What it means

P1418. Secondary Air Injection System Relay A Control Circuit High. This Chevy-enhanced code applies to Silverado, Sierra, Tahoe, Yukon, Corvette.

Findings, check these first

Failed AIR pump relay with welded contacts in the underhood fuse block
Short to voltage on the relay control circuit from the PCM
Corroded relay socket terminals in the underhood electrical center
Faulty PCM driver holding the relay control circuit high

Standard procedure

Swap the AIR relay with a known-good identical relay and retest before buying parts
Test the relay control circuit for a short to voltage with a multimeter
Inspect the underhood fuse block for green corrosion on the relay pins
Verify PCM command with a Tech2/GDS2 scan tool before condemning the module

Look up another code

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Sources and review

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Last updated 2026-09-13.

Report a correction for P1418. Include your vehicle, the issue and a source if you have one.