What causes a SPN 70 code?

SPN 70 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 70 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 70 active.

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 70

J1939 SPN 70 — Engine parameter

What it means

Inlet Air Heater Driver Circuit - The ECM has detected a fault (open circuit, short to ground, or short to power) in the intake air heater system used for cold starts.