The throttle motor is not drawing the current the ECU expects. Usually the motor itself or its supply.
P2102 — also written P21O2, P 2102, 2102 — is the OBD-II code for throttle actuator control motor circuit low. Same code, same fix: this page covers every spelling of it.
P2102 is a engine fault code, typically costing £90–£550 to put right in a UK garage.
What causes P2102?
- Failed throttle body motor
- Blown fuse or broken supply wire
- Corroded throttle connector
- Carbon jamming the throttle plate
How P2102 is fixed
- Clean the throttle body and carry out an adaptation reset
- Test the motor's supply and resistance
- Replace the throttle body and code it if required
P2102 repair cost in the UK
Most P2102 repairs land between £90–£550 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Can you drive with P2102?
Expect limp mode with very limited power. Recover if it will not accelerate safely.
Urgency: high.
What P2102 is telling you
The ECU runs continuous plausibility checks against what a good engine should be doing. When a reading strays outside that model for long enough, this code is stored and the light comes on.
On P2102 specifically — throttle actuator control motor circuit low — the stored code records the moment that check failed, not the moment the part gave up. That gap is why two cars with the same code can need completely different repairs.
How P2102 is diagnosed properly
Each of the known causes is ruled in or out in cost order, cheapest and most likely first. On P2102 that means working through them like this:
- Failed throttle body motor — confirmed with live data before any part is bought.
- Blown fuse or broken supply wire — checked with the loom flexed and the engine warm, because a wiring fault that is intermittent when cold shows itself under heat and vibration.
- Corroded throttle connector — opened, inspected for green corrosion and spread pins, and back-probed rather than unplugged, so the reading is taken with the circuit live.
- Carbon jamming the throttle plate — measured as a pressure or flow difference across the component, so a partial restriction is not mistaken for a clear one.
An hour of diagnostic time on P2102 routinely saves more than it costs, because the alternative is buying the most expensive part on that list and hoping.
The repairs that actually clear P2102
- Clean the throttle body and carry out an adaptation reset
- Test the motor's supply and resistance
- Replace the throttle body and code it if required
After the repair the code is cleared and the car is driven until the relevant readiness monitor completes, rather than handed back as soon as the light goes out. A code that has only been erased will come straight back on the next drive cycle.
What happens if P2102 is ignored
Leaving this one is the expensive choice. The protection strategy the ECU falls into is there to limit damage, and every mile driven with the fault active is a mile the engine or gearbox spends outside its designed operating window.
For reference, P2102 typically lands at £90–£550 all-in at an independent garage in the UK — main-dealer quotes for the same job usually sit above that.
Getting P2102 looked at
Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P2102 is showing on your car, bring the scan results with you — we will read the live data ourselves, tell you which of the causes above it actually is, and price the repair before any work starts.