Powertrain, generic · Fuel and air metering (injector circuit)

P0221 Throttle/Pedal Position Sensor/Switch B Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

With electronic throttle control the throttle body carries two position sensors, A and B, usually with opposite or offset signals, and the engine module compares them (correlation code P2135). GM and Ford give the pedal sensors their own codes (P2120 ff), so B is in practice the second throttle sensor. P0221 is the plausibility fault: the signal of sensor B is electrically valid but does not match sensor A or the throttle position expected from airflow. Bosch ME9 engines (Saab) set it at a deviation of more than 9 %, older Ford systems at more than 7 degrees between the sensors without the warning light; many newer engines report this only as P2135. The module carries on with sensor A, limits throttle opening and power and switches off cruise control.

Likely causes

Worn track of sensor B (signal jumps)
Contact resistance at connector or wiring
Throttle dirty or sticking
Mass airflow sensor fault or false air

Symptoms

  • Check engine light on
  • Limp mode, reduced power
  • Rough idle, jerking
  • Cruise control disabled

Repair estimate

DifficultyMediumDIY possible
Parts and labour€80–600
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

throttle position sensor belectronic throttle bodysensor wiring

Related codes

P0121P0220P0222P0223P2135P0068

References: law.cornell.edu, saabwisonline.com, saabwisonline.com, newtonnet.co.uk.