P2164: Throttle/Pedal Position Sensor B Maximum Stop Performance

What it means

Throttle/pedal position sensor B does not reach the calibrated maximum-stop value during the wide-open self-test. Sensor wear, mechanical stop misalignment, or a stuck pedal.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

Throttle/pedal position sensor B reports how far the throttle or accelerator pedal has moved as part of the electronic throttle system. The control module compares sensor B's reading with its calibrated endpoint during a wide-open self-test; this code sets when the reading falls short of the expected maximum.

Common causes

Most likely first.

1. Throttle or pedal position sensor B worn or faulty
2. Throttle or pedal mechanism not reaching its calibrated stop
3. Binding throttle or pedal linkage
4. Damaged wiring or connector

Symptoms

• Check engine light on
• Reduced throttle response, possible limp mode
• Hesitation or surging
• Idle too high or too low

How to diagnose it

1. Use a scan tool to save freeze-frame data and compare live sensor B readings with the other throttle or pedal position sensors as the pedal is moved slowly through its range.
2. With the engine off, check that the pedal and throttle mechanism move freely and can reach their intended full-travel stop without obstruction.
3. Inspect sensor B's connector and wiring for loose or backed-out pins, corrosion, chafing, or damage that could interrupt its signal.
4. Check sensor B's signal and reference or ground circuits while moving the pedal, looking for dropouts or a maximum reading that does not agree with the manufacturer's specification.
5. If the wiring and mechanical travel are sound, test sensor B and the throttle or pedal assembly using the manufacturer's procedure to distinguish sensor wear from stop or calibration problems.

Common fixes

• Remove an obstruction or correct binding that prevents full pedal or throttle travel.
• Repair a loose, damaged, or corroded sensor B connector or wire.
• Repair or replace the worn throttle or pedal position sensor B, or its assembly if integrated.
• Correct a misaligned mechanical stop or perform the specified throttle or pedal relearn.

Can I keep driving?

Drive only if throttle response remains predictable, and avoid overtaking or situations that require rapid acceleration. If response becomes erratic or reduced, stop somewhere safe; continued driving can make the vehicle difficult to control in traffic.