Electronic throttle body codes

How its codes differ

• P2111 (stuck open) and P2112 (stuck closed) mean the computer commanded the plate to move and it did not follow. A worn motor, worn internal position sensor or a plate bound by carbon or ice are the usual suspects.
• P2101 and P2119 are performance codes: actual throttle position does not match what the computer asked for. They point at the motor, its gears, the internal sensor or the wiring, and on some models a dirty plate.
• P2135 means the two throttle position signals stopped agreeing with each other. Because those sensors are built into the throttle body on most cars, the fix is often the whole assembly, though wiring and connectors come first.
• P2104 (forced idle) and P2106 (forced limited power) are the computer's fail-safe responses, not faults on their own. Look for the throttle or pedal code stored alongside them and fix that.
• Pedal sensor codes (P2122, P2138) can put the car into the same limp mode, but the fault is at the pedal, not the throttle body.

Codes

• P2101

  The engine computer sees a problem in the throttle actuator motor circuit or the motor's response, so actual throttle position doesn't match what was commanded

  Severity: Inspect soon

• P2104

  The engine computer has forced the engine to idle as a fail-safe because of a throttle control fault

  Severity: Inspect soon

• P2106

  The engine computer has limited engine power as a fail-safe because of a throttle control fault

  Severity: Inspect soon

• P2111

  The engine computer commanded the electronic throttle to close further but saw it stay more open than expected

  Severity: Inspect soon

• P2112

  The engine computer commanded the electronic throttle to open but saw it stay more closed than expected

  Severity: Inspect soon

• P2119

  The electronic throttle body's actual position doesn't match the position the engine computer expects

  Severity: Inspect soon

• P2135

  Two throttle or pedal position sensor signals (A and B) that should agree with each other don't

  Severity: Inspect soon

Signs it's failing

• Check engine light, often with a wrench or reduced-power message
• Limp mode: engine held at idle or at limited speed and power
• Poor or no response to the accelerator pedal
• Rough, high or low idle, or stalling
• No-start on some cars when the throttle is stuck closed

How to test it

1. Read all stored codes with a scan tool. If a forced-idle or limited-power code is stored, find the throttle, pedal or wiring code that caused it. (Low risk)

2. With the engine off, look at the throttle body connector and harness for a loose plug, corrosion or chafed wires. (Low risk)

3. Testing the motor and position sensor circuits, cleaning the throttle body and replacing it are jobs for a shop. After any of these the computer usually needs a throttle relearn. (Best left to a shop)

   Warning: The throttle motor is strong enough to injure fingers. Never put fingers in the throttle bore or push the plate by hand with the ignition on or the battery connected. Do not spray cleaner into the throttle body: it can soak into the electronics.

After the repair

• Make sure the throttle relearn or idle relearn has been done; a new or cleaned throttle body can idle badly until it is.
• Check whether your vehicle has a software update or extended warranty for throttle body faults before paying for a replacement.
• Clear codes only after the repair and confirm the reduced-power warning does not return on a test drive.