What it means
The TAC monitor restricts maximum throttle opening as a safety response to a TAC fault. The vehicle can still be driven, but accelerator pedal travel is capped.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The throttle actuator control system can cap throttle opening to limit engine power when it detects a fault. P2106 records this forced limited-power response; it does not by itself identify the underlying fault, which may include implausible accelerator-pedal signals.
Common causes
Most likely first.
- Underlying TAC fault triggers limit
- Pedal position sensor signal implausible
Symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
How to diagnose it
- Record freeze-frame data and scan for companion codes that identify the fault behind the limited-power command.
- Review live accelerator-pedal signals and commanded versus actual throttle position for dropouts or implausible changes.
- Inspect the pedal and throttle-body connectors and wiring for looseness, corrosion, chafing, or damage.
- Test the pedal-position and throttle-actuator circuits indicated by the codes using the wiring diagram and manufacturer's procedure.
- Repair the underlying cause, then confirm that throttle response and power limitation return to normal under the approved test conditions.
Common fixes
- Repair a loose, corroded, or damaged pedal or throttle-body connection.
- Repair wiring faults affecting pedal-position or throttle-actuator signals.
- Replace a pedal sensor, throttle actuator, or throttle body only when testing confirms failure.
- Complete any required relearn after repairs.
Can I keep driving?
The vehicle may have too little power for safe merging, climbing, or keeping pace with traffic; avoid those situations and drive only as needed to reach a safe location. If power loss is severe or unpredictable, stop and arrange recovery.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.