Is P2105 saying my engine is damaged?

No. P2105 is a safety decision by the engine control module, not a report of mechanical damage. The module concluded it could not trust the electronic throttle and cut fuel and spark rather than allow an engine it cannot control to keep running. The engine itself is almost always fine. What needs repair is whatever the companion code identifies — a sensor, a motor circuit, wiring, or in many cases something as ordinary as system voltage.

How is P2105 different from P2104 and P2110?

They are three escalating tiers of the same protective strategy. P2110 caps engine speed but leaves the vehicle limpable. P2104 locks the throttle to idle — the engine runs but will not accelerate. P2105 is the top tier: the module shuts the engine down and will not let it run while the fault is present. Which one the module chose is a direct readout of how severe it judged the throttle fault to be, and P2105 means it judged it severe.

My car cranks but will not start with P2105. Where do I begin?

Begin with the battery and the grounds, before anything expensive. Low or unstable system voltage is one of the most common reasons the throttle correlation checks fail, and it is free to test. Then read all stored codes and look at both pedal and both throttle position sensor signals in live data — a single failed sensor among a redundant pair is exactly the kind of fault that triggers the top-tier response. Check for aftermarket alarm or remote-start wiring in those circuits too; it comes up more often than people expect.

Can I clear the code and drive it home?

You should not. Clearing the code does not repair anything, and the module will shut the engine down again as soon as it re-detects the fault — possibly while you are moving, at which point you lose power steering and brake assist at the same moment. Have it towed. This is one of the few codes where the honest advice really is do not drive it, and that advice comes from the consequences of a mid-drive shutdown rather than from any risk to the engine.

OBD-II trouble code

P2105: Throttle Actuator Control System - Forced Engine Shutdown

The engine control module judged a throttle control fault severe enough to shut the engine down rather than let it run. The vehicle will stall or refuse to start while the fault is present. This is the highest tier of the throttle fail-safe strategy and is a safety response, not a failed component.

High severityPowertrainFuel & Air MeteringDo not drive

Quick facts

System: Powertrain
Category: Fuel & Air Metering
Severity: High severity
Drivable: No — stop driving until repaired
Repair cost range: $0 – $1,000
DIY difficulty: Intermediate DIY

What does P2105 mean?

Every drive-by-wire vehicle carries a set of redundant sensors — two in the accelerator pedal, two in the throttle body — for one reason: so the engine control module can cross-check them and detect a fault before the throttle does something the driver did not ask for. When those cross-checks fail, the module has a tiered response. It can cap engine speed (P2110), it can lock the throttle to idle (P2104), or, when it concludes it cannot safely allow the engine to run at all, it can cut fuel and spark and shut the engine down. P2105 is that last option.

Because of that, P2105 is a declaration rather than a diagnosis. It does not name a broken part. It says the module found the throttle system untrustworthy enough that continuing to run the engine posed an unacceptable risk of uncommanded acceleration. The code that names the actual fault will be stored alongside it — commonly a throttle actuator motor circuit code (P2100, P2102, P2103), a throttle position sensor or correlation code (P0122, P0123, P2135), or an accelerator pedal position code (P2138). The repair is whatever that companion code identifies.

The practical experience is unmistakable: the engine dies, often without warning, and either will not restart or starts and immediately stalls again. Some vehicles will crank normally and never fire. Because the shutdown can happen while moving, this code carries real safety weight — power steering assist and vacuum brake assist are lost when the engine stops, which makes an already stressful situation harder to handle. Anyone who experiences this should get the vehicle off the road and towed rather than attempting repeated restarts to limp somewhere.

Two causes deserve early attention because they are common and cheap to rule out. Low system voltage — a failing battery, a corroded terminal, a dying alternator — makes the throttle actuator sluggish and the sensor reference voltages unstable, which is enough to fail the correlation checks and trigger a throttle fault that has nothing to do with the throttle body. And aftermarket wiring, particularly remote starts and alarms spliced into ignition, pedal, or throttle circuits, is a recurring source of exactly this fault. Neither costs anything to check, and both are checked before anyone should be quoting a throttle body.

Common causes

Companion throttle actuator control fault (P2100, P2102, P2103) severe enough to trigger shutdown
Both throttle position sensor signals failing or disagreeing badly
Both accelerator pedal position sensor signals failing or disagreeing badly
Short to power or ground in the throttle actuator motor circuit
Failed throttle actuator control motor or a seized throttle plate
Damaged, chafed, or corroded wiring in the throttle or pedal harness
Low system voltage from a weak battery, corroded terminals, or a failing alternator
Poor engine or module ground shifting sensor reference voltages
Aftermarket alarm, remote start, or accessory wiring spliced into throttle, pedal, or ignition circuits
Water intrusion into the throttle body or pedal connector
Failed engine control module (rare — verify wiring, grounds, and voltage first)

Symptoms

Engine shuts down while running, sometimes without warning
Engine cranks but will not start, or starts and immediately stalls
Check engine light on, typically with a reduced-power or wrench warning
Loss of power steering assist and brake booster vacuum when the engine stops
Companion throttle or pedal codes stored alongside P2105
Fault may clear after a key cycle and recur during the next drive
Dashboard warnings for multiple systems as the engine loses power

Diagnostic steps

1.Get the vehicle to a safe location and have it towed. Repeated restart attempts to limp it somewhere are not worth the risk of another shutdown in traffic.
2.Scan and record every stored and pending code from all modules before clearing anything. P2105 is the response; the companion code is the fault.
3.Load-test the battery and verify charging output and terminal condition. Low or unstable voltage causes throttle faults that no parts replacement will resolve.
4.Inspect the throttle body and pedal connectors for corrosion, water intrusion, backed-out pins, and broken locking tabs.
5.Compare commanded versus actual throttle position in live data during a key-on self-test — most vehicles sweep the throttle briefly at key-on, and watching that sweep is informative.
6.Graph both accelerator pedal position signals together while sweeping the pedal. They should track smoothly across the full range; a flat spot, dropout, or divergence identifies the fault.
7.Graph both throttle position signals the same way, looking for a signal stuck at one value or dropping out.
8.Remove the intake ducting and check whether the throttle plate moves freely against spring pressure with the connector unplugged. A seized plate is a mechanical cause the module reads as a control failure.
9.Check for aftermarket wiring spliced into throttle, pedal, or ignition circuits and disconnect it for testing if found.
10.Voltage-drop test the engine and module grounds under load rather than checking continuity at rest.
11.Repair the confirmed fault, perform the manufacturer's throttle relearn procedure, then verify across a full drive cycle with the codes cleared.

Repair cost

$0 – $1,000

The low end is zero because a loose battery terminal, an unplugged connector, or an aftermarket accessory that needs unhooking are all genuine no-parts fixes. Battery or alternator work typically runs $150-$700. A replacement throttle body commonly runs $250-$700 installed including the required relearn, and an accelerator pedal assembly $150-$400. Wiring repair varies widely with the length of harness affected. Add a tow to any of these, since the vehicle is not driveable. As with every fail-safe code, the real cost is set by the companion fault, not by P2105 itself.

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DIY vs shop

This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.