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

What Does P0221 Mean?

Code P0221 indicates that the secondary throttle position sensor (TPS B) is reporting a signal that is erratic, out of range, or does not correlate with the primary TPS signal. Modern throttle bodies use dual sensors for redundancy and safety. When the signals disagree or TPS B is erratic, the ECM may enter limp mode to protect the engine and drivetrain.

Common Causes

• Faulty throttle position sensor
• Carbon buildup on throttle body affecting sensor readings
• Damaged wiring or connector at throttle body
• Failed electronic throttle body assembly
• Intermittent electrical connection

Symptoms

• Check engine light on
• Reduced engine power or limp mode
• Erratic or surging idle
• Poor throttle response
• Vehicle may not accelerate past a certain speed

Diagnostic Steps

1. 1Read TPS A and TPS B values with scan tool and compare for correlation
2. 2Clean throttle body and re-test sensor readings
3. 3Check TPS wiring for damage, loose connections, or corrosion
4. 4Verify 5V reference and ground signals at the TPS connector
5. 5Monitor TPS signals during slow throttle sweep for dropouts or dead spots
6. 6Replace throttle body assembly if cleaning does not resolve the issue

Estimated Repair Cost

Frequently Asked Questions