P0488: Ford throttle open-position learning is outside its limits

Ford's 2015 diesel summary associates P0488 with throttle-valve offset learning. The learned position is for the throttle's open position. The code is set when that learned value falls outside the calibrated limits, even though the generic title refers to EGR throttle control range/performance.

A shutdown learning event

Ford describes the learn occurring when the engine shuts down with coolant typically above 70°C. The diagnostic decision occurs immediately at completion of the offset learn. This differs from an electrical fault monitored continuously while the throttle power stage is on.

The printed internal offset limits are not accompanied by a physical angular unit. They should not be converted into a universal throttle-angle adjustment or external meter specification.

Verify the learning result

Establish that the appropriate shutdown learning event completed and retain any accompanying throttle circuit codes. P02E0, P02E2 and P02E3 address electrical control faults in the same source; P0488 describes the learned offset result. The monitor alone does not prove that cleaning, adjustment, software or valve replacement is the correct remedy. Follow the vehicle-specific throttle diagnostic and learning procedure, keeping clear of an actuator that may move during shutdown.

Source and applicability

Ford 2015 model-year diesel OBD system operation summary, revision December 22, 2014; the cited monitor only, without blanket model or engine applicability. Ford source, physical PDF page 138. The documented monitor explains the fault decision; vehicle-specific service information is still needed for connector identification and a complete repair procedure.