What causes a P1558 code?

P1558 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 P1558 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1558 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

P1558

Coolant level sensor under range two

What it means

P1558 indicates that the Engine Control Module detected the coolant level sensor signal voltage is below the 'under range' threshold (typically below 0.5V), suggesting a short circuit or sensor failure.