What causes a SPN 4342 code?

SPN 4342 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 4342 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with SPN 4342 active.

How do I fix SPN 4342?

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 4342

Detroit DD13/DD15/DD16 SPN 4342

What it means

Aftertreatment 1 SCR DEF Suction Line Heating - Voltage Below Normal or Shorted Low. Indicates a circuit or performance issue with the DEF suction line heating element.