P2621Throttle Position Output Circuit Low
- Generic OBD-II code · Powertrain
- Matters for the ITP
- How the car detects it
- P2621 flags the throttle position output line as shorted to ground or reading below its permitted voltage band. A receiving module such as a transmission controller would then see a value that looks like a fully closed throttle all the time. No carmaker publishes a code-specific description with limits; the CARB requirement for output monitoring and GM's output-driver tests on the crank signal (0.5 ohm toward ground counted as a short, 40 failures in 50 samples) illustrate the usual method, but they are an analogy, not a documented P2621 strategy. Check the wire between the two modules for chafing against body ground and the connectors for corrosion before suspecting either controller. Compared with P2620 (open line) and P2622 (short to supply), the receiver here gets a steady low level.
- What you may notice
- Stored code in the engine module
- Receiver behaves as if the throttle were always closed (late or odd shifts)
- Likely causes
- LikelyOutput wire chafed against body ground
- PossibleCorrosion bridging the output pin to ground
- RareShorted input in the receiving module
- Inspection (ITP)
- Can matter for the ITP: it concerns the emissions system.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.