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U0107 Lost Communication With Throttle Actuator A Control Module

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

U0107 targets a stand-alone throttle actuator control (TAC) module, as used before throttle control moved into the engine controller. In GM's 2004 and 2005 truck tables (4.3–6.0 L and 8.1 L) the PCM and TAC module traded data over a dedicated serial link; the PCM declared a gap after 18.75 ms and the TAC module after 25 ms. Each missing or corrupt message added 10 to a counter, each valid one took 1 away, and 500 ms without valid data produced a Type A code with MIL on the first trip. Without this link the electronic throttle is no longer cross-checked, so the engine usually runs with restricted power. U0408 covers invalid TAC data and U0308 a software mismatch.

Likely causes

Open, shorted or chafed serial data lines between PCM and TAC module
TAC module supply or ground faulty
Corroded connector at the TAC module
TAC module internally faulty

Symptoms

  • MIL on
  • Reduced engine power, throttle barely opens
  • Idle unstable or engine stalls

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–700
Time0.5–3 h

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

Parts involved

throttle actuator control modulecan bus wiring

Related codes

U0100U0308U0408

References: gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.