P2108
Throttle Actuator Control Module Performance
Self-tests within the TAC module fail their performance criteria — for example RAM/ROM checks or analog reference voltages drift. Indicates an aging ECU rather than a wiring fault.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Common causes
Ordered by how often each turns out to be the cause.
- ECU internal performance faultCommon
- ECU connector pins corrodedLess likely
- Module software outdated, reflash may resolveLess likely
Parts involved
- ECM
P2108 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.