What causes a SPN 3629 code?

SPN 3629 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 3629 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 3629 active.

How do I fix SPN 3629?

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 3629

J1939 SPN 3629 — Body/Chassis parameter

What it means

Aftertreatment 1 Diesel Oxidation Catalyst Intake Gas Pressure. Note: While the user provided 'Body/Chassis' context, SPN 3629 in modern J1939 (Cummins/Detroit) typically refers to the DOC Intake Pressure sensor signal.