What causes a P1137 code?

P1137 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 P1137 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P1137 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

P1137

WRAF heater supply voltage test fault

What it means

The engine control module (ECM) has detected that the voltage supplied to the Wide-range Air Fuel (O2) sensor heater circuit is outside of the calibrated range. This prevents the sensor from reaching its operating temperature quickly enough for accurate emissions control.