What causes a P2104 code?

P2104 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 P2104 code?

Drivability depends on the severity. Check the severity rating and verified driver reports on this page before continuing to drive with P2104 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

P2104

Throttle Actuator Control System - Forced Idle

What it means

The Engine Control Module (ECM) has detected a serious fault with the electronic throttle control system and has defaulted to a forced idle state to prevent unintended acceleration.