P2107

P2107 means the ECU has detected a fault in the throttle actuator control module's internal processor — the dedicated microcontroller that manages the closed-loop control of the electronic throttle body has failed an internal self-check, lost communication with the main ECU, or detected a hardware error in its own circuitry. On most modern vehicles the TAC processor is integrated into the main ECU/PCM rather than a standalone module, so P2107 is typically an ECU-internal fault rather than a wiring or sensor issue. The cheapest-first ladder: check ECU power and ground integrity first — voltage drop at the ECU main power feed should be under 0.1V under full load, ground continuity to chassis under 0.3 ohms. A failing ECU ground is the single most common cause of phantom processor codes; pull and clean the engine-to-chassis ground strap and the ECU's dedicated ground points. Scan-tool the battery voltage feed seen by the ECU at idle and at 2,500 RPM — it should track battery voltage within 0.2V; a sagging voltage feed from a tired battery or a corroded fuse box causes the ECU to fail its internal voltage rails check and set P2107. Verify the ECU is at the current calibration level — a missed flash update will set P2107 on some platforms after a battery disconnect, and the fix is a re-flash rather than a module replacement. The expensive-misdiagnosis caveat: don't replace the ECU on a standalone P2107 without first verifying power, ground, and software calibration — a new ECU is $600-$2,000 plus dealer programming, but a $5 wire-brushed ground strap or a free re-flash clears most of these codes; ECU replacement should be the last step after every external cause has been ruled out.

Vehicle-specific patterns: 2007-2014 GM Vortec 5.3/6.0 trucks/SUVs throw P2107 less often than P2104/P2105 but follow the same pattern when the main PCM ground at the cylinder head develops corrosion; a wire-brush and dielectric grease typically clears it. 2010-2014 Ford F-150 3.5 EcoBoost throws P2107 from PCM internal voltage rail faults that almost always trace back to a corroded battery terminal or a failing alternator with high AC ripple; check ripple voltage under 0.1V AC before condemning the PCM. 2008-2014 Chrysler/Dodge 3.6 Pentastar (Town & Country, Journey, Charger) throws P2107 from a documented PCM connector pin-fretting issue at the C1 connector; re-seat and grease the connector pins. 2007-2013 BMW E90/E60 throws P2107 (DME processor faults) from internal DME failures that BMW occasionally covered under emissions warranty. Estimated repair: $0 (clean ground/connector) to $2,000 (PCM replacement + programming).