What causes a SPN 626 code?

SPN 626 can be triggered by several issues — see the verified probable causes and step-by-step diagnostics shared by mechanics and owners on OBDIY.

Can I drive with a SPN 626 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 626 active.

How do I fix SPN 626?

Follow the step-by-step diagnostic on this page, then read the verified fixes contributed by other Heavy Truck owners — the answer marked "Verified Cause" worked for the original poster.

OBDIY

J1939 SPN

SPN 626

SPN 626 - Intake Air Heater 1 Relay Control Circuit

What it means

Indicates a mechanical or electrical failure in the circuit controlling the intake air heater relay used for cold weather starting.