OBD-II Code · Fuel & Air
P2100
Throttle Actuator Control Motor Circuit/Open
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$100–$500
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Drive-by-wire throttle motor circuit open — actuator not responding.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Limp home mode
- Reduced power
- Speed capped 25-30 mph
- Check engine light
Likely causes
- Worn throttle motor brushesMost common
- Corroded throttle-body connector
- Failed ECM H-bridge driver
- Carbon-bound throttle blade
Read the full diagnostic procedureP2100 means the ECM has lost continuity on the throttle actuator control motor circuit — the electric motor that physically opens and closes the thro…
P2100 means the ECM has lost continuity on the throttle actuator control motor circuit — the electric motor that physically opens and closes the throttle blade on a drive-by-wire (ETC) system isn't responding, or its circuit reads as open. This is not a sensor code; this is the actuator itself or its dedicated H-bridge driver in the ECM. The car will be in limp-home mode within seconds of this code setting — typically forced idle around 1,000-1,500 RPM with a hard cap that won't let you above 25-30 mph.
Cheapest-first diagnostic
- pop the throttle body off and look at the blade.
- If it's coated in coffee-ground carbon (the norm past 60k miles), a $100 throttle-body cleaning service often clears it because the motor was binding against deposits and the ECM finally gave up.
- If the blade is clean, inspect the 6-pin connector at the throttle body for backed-out pins, green corrosion, or melted plastic from exhaust-manifold heat soak.
- Then backprobe the two motor-drive wires with a DMM keyed-on — you should see roughly battery voltage on one and ground on the other as the ECM commands the blade open, then they should reverse to spring it closed.
- If both pins read 0V or both read battery, the ECM driver is dead; if one reads battery and the motor doesn't move, the motor winding is open.
Vehicle-specific patterns2005-2010 Ford Five Hundred / Taurus / Mercury Montego with the 3.0L Duratec is the classic P2100 callback — the throttle-body actuator motor brushes…
- 2005-2010Ford Five Hundred / Taurus / Mercury Montego with the 3.0L Duratec is the classic P2100 callback — the throttle-body actuator motor brushes wear out around 90-120k miles and the entire throttle body has to be replaced (Ford doesn't sell the motor separately), running $300-500 in parts plus an hour of labor and the relearn.
- 2003-2007Cadillac CTS / SRX with the 3.6L LY7 throws P2100 from the same wear-out pattern, often with a P2101 companion code.
- 2007-2012Nissan Altima / Maxima VQ35 sees P2100 from a known harness chafe at the throttle-body connector where it routes over the valve cover — repin or replace the pigtail and the code clears.
- 2008-2014Mini Cooper R56 throws P2100 from internal water intrusion into the throttle body when the cowl drains plug; dry it out and reseal the cowl. Critical: NEVER clear a P2100 without running the throttle-relearn procedure (key-on / engine-off / 30-second wait / cycle key) — the ECM stores blade-stop positions in volatile memory and a fresh install with no relearn will throw the code right back in 5 miles.
Look up another code
P2100 — frequently asked
What does a P2100 code mean?
Drive-by-wire throttle motor circuit open — actuator not responding.
What causes a P2100 code?
Common causes: Worn throttle motor brushes; Corroded throttle-body connector; Failed ECM H-bridge driver; Carbon-bound throttle blade.
What are the symptoms of a P2100 code?
Typical symptoms: Limp home mode; Reduced power; Speed capped 25-30 mph; Check engine light.
Is it safe to drive with a P2100 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $100-$500.
How do I diagnose a P2100 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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