OBD-II trouble code
P2107: Throttle Actuator Control Module Processor
The processor that runs the electronic throttle failed its own internal self-test. The module is not reporting a fault out in the wiring — it is reporting that it no longer trusts its own calculations, and it takes authority away from the throttle as a result.
Quick facts
- System
- Powertrain
- Category
- Fuel & Air Metering
- Severity
- High severity
- Drivable
- No — stop driving until repaired
- Repair cost range
- $150 – $1,400
- DIY difficulty
- Shop recommended
What does P2107 mean?
Every drive-by-wire vehicle has a section of software and silicon whose only job is to run the throttle. It reads the two accelerator pedal sensors, decides how far the throttle plate should open, drives the actuator motor, then reads the two throttle position sensors to confirm the plate went where it was told. Because an error anywhere in that loop could open a throttle nobody asked to be opened, the design is deliberately paranoid: the processor continuously checks itself, often by running the same calculation twice on separate paths and comparing the answers.
P2107 sets when that self-check fails. This is the important distinction and the reason the code behaves so differently from its neighbors. P2100, P2102 and P2103 are circuit codes — a wire is open or shorted. P2118 is a current code. P2119 is a positioning code. P2107 is none of those: the sensors may be fine, the motor may be fine, the wiring may be fine, and the module has still decided that the part of itself responsible for commanding the throttle produced an answer it cannot verify. When a safety-critical processor cannot confirm its own math, the only acceptable response is to stop acting on it, so the module surrenders throttle authority and the plate falls back to its spring-loaded default position.
On many platforms the throttle actuator control function lives inside the main powertrain control module. On others — a number of General Motors, Ford, Chrysler and European applications among them — it is a separate throttle actuator control module mounted near the throttle body or the fuse box. Which architecture your vehicle uses changes the repair completely, so identifying it in service data is the first real diagnostic step rather than an afterthought.
Before accepting that a processor has genuinely failed, the honest diagnostic path goes through power quality. An internal processor fault is a plausible outcome of marginal voltage, a bad module ground, or electrical noise from a failing alternator with leaky diodes, and all three are far more common and far cheaper than a dead module. A weak battery cranking a modern vehicle can drop system voltage low enough that a module's internal checks legitimately fail — the processor was right to distrust itself, but the cause was the electrical system, not the silicon. Corroded grounds and a charging system with excessive AC ripple do the same thing intermittently, which is exactly the pattern of a code that comes and goes.
Expect the vehicle to be in a reduced-power or forced-idle state, and expect a fail-safe code from the P2104 / P2105 / P2106 / P2110 group stored alongside this one. That companion code tells you what the module chose to do about the fault; P2107 tells you why.
Common causes
- Weak or failing battery allowing system voltage to sag below the module's operating threshold
- Failing alternator producing excessive AC ripple or voltage spikes
- Corroded, loose, or high-resistance module ground
- Corroded or damaged battery terminals and cables
- Water intrusion into the throttle actuator control module or its connector
- Chafed or shorted wiring feeding the module's power or ground circuits
- Genuine internal failure of the throttle actuator control module or of the PCM's throttle control section
- Damaged module connector — backed-out pin, spread terminal, or broken locking tab
- Aftermarket alarm, remote start, or performance tuning wiring spliced into module power, ground, or throttle circuits
- Corrupted or interrupted module software from a failed reflash or a battery disconnect mid-programming
- Jump-start or charging done with reversed polarity or with the vehicle running
- Rodent damage to the harness near the module
Symptoms
- Check engine light on, usually with a reduced-power or wrench warning
- Reduced engine power or limp mode with the throttle capped
- Engine cranks but will not start, or starts and immediately returns to idle only
- Throttle completely unresponsive to the accelerator pedal
- Rough or unstable idle
- Multiple unrelated codes stored at once, which is itself a clue about voltage or grounds
- Symptom appears at cold start or after the vehicle sits, then clears at the next key cycle
- A fail-safe code from the P2104 / P2105 / P2106 / P2110 group stored alongside it
Diagnostic steps
- 1.Scan every module and record all stored and pending codes with freeze frame data. A long list of codes across unrelated systems points hard at power supply or grounds rather than at a failed processor.
- 2.Determine from service data whether your vehicle uses a standalone throttle actuator control module or handles the function inside the PCM. Everything about the repair path depends on this answer.
- 3.Load-test the battery and inspect the terminals and cables. This step comes first because low voltage can legitimately cause a module's internal self-check to fail on otherwise healthy hardware.
- 4.Test the charging system for output voltage and for AC ripple. Excessive ripple from failing alternator diodes produces exactly this kind of intermittent internal fault.
- 5.Perform a voltage-drop test on the module's ground circuits with the engine running. A ground that measures continuity at rest can still be too resistive under load.
- 6.Verify the module's power feeds at the connector with the key on, and check the associated fuses and relays.
- 7.Inspect the module and its connector for water intrusion, corrosion, green residue on the pins, and backed-out or spread terminals.
- 8.Ask whether the vehicle recently had a battery replacement, jump-start, module reflash, alarm installation, remote start, or performance tune. Any of those is a realistic trigger and worth knowing before you condemn hardware.
- 9.Clear the code, run the throttle relearn procedure, and drive the vehicle to see whether P2107 returns as a hard fault or stays away. A code that does not come back after correcting a voltage or ground problem was never a processor failure.
- 10.Only after power, grounds, connectors, and companion codes are all confirmed good should the module be replaced. Nearly all replacements require programming to the vehicle, and many also require a throttle relearn and an immobilizer or key relearn.
Repair cost
$150 – $1,400
The low end covers the outcomes that are not a module at all — a battery, a cleaned and retightened ground, a repaired connector, or a charging system fault, typically $150-$450 with diagnostic time included. A standalone throttle actuator control module runs roughly $250-$700 for the part plus programming, landing near $400-$900 installed. When the throttle control function is inside the powertrain control module, replacing it is the expensive path: $500-$1,400 or more installed, because the module must be programmed to the vehicle and often relearned to the immobilizer as well. Diagnostic time is a larger share of this bill than usual, and that is money well spent — the whole point is to avoid buying a module for a bad ground.
Estimate your repair
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Open the Repair Cost Estimator with control module replacement & programming preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.