What causes a P1684 code?

P1684 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 P1684 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1684 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

OBD-II

P1684

Oil level driver short circuit low

What it means

The ECM has detected the return voltage from the oil level sensor circuit is lower than the commanded or expected range, indicating a short to ground.