Powertrain, generic (extended)

P2104 Throttle Actuator Control System - Forced Idle

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2104 is a status code: it does not name a broken part but records that the throttle control has switched into a forced-idle failure mode. In Ford's 2012 summary this happens on second-generation ETC systems when two or three accelerator pedal sensor tracks are lost, so the computer can no longer read driver demand; the engine then holds a raised idle and ignores the pedal, with MIL and wrench lamp. The actual cause is stored alongside it, usually a pedal sensor code such as P2122-P2128 or P2138. CARB counts such default modes as malfunctions whenever they can raise emissions. Repair means fixing the causal code, then clearing P2104. Related states are limited power (P2106), limited rpm (P2110) and shutdown (P2105).

Likely causes

Failure of two or more accelerator pedal sensor tracks
Pedal sensor wiring or shared 5 V reference fault
ECU input or software fault

Symptoms

  • Engine stays at raised idle, pedal has no effect
  • Engine and ETC/wrench warning lamps on
  • Car can only creep to a safe place

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–400
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

throttle actuator controlecm

Related codes

P2105P2106P2110P2122P2127P2138

References: newtonnet.co.uk, law.cornell.edu.