P05DC: GM brake-pedal B range and PWM performance

GM's cited BSC2 table defines P05DC as brake-pedal position sensor B circuit range/performance. Several monitor branches share this code, so its title does not identify one single electrical failure mode.

Position range and signal format are separate checks

One branch evaluates whether reported travel falls outside the documented physical range, above 47 mm or below −0.5 mm. Another checks the pulse-width-modulated signal's frequency and duty cycle against permitted limits. The source describes a nominal 1 kHz sensor module.

A signal can therefore fail because its decoded position is implausible or because its timing format is unacceptable. Seeing a changing voltage is not proof that either check passes. Conversely, a plausible displayed travel value may not reveal brief communication-format errors.

Confirm the affected channel and branch

This code concerns channel B. The adjacent A-channel procedure and an A/B correlation fault are related but do not establish the same evidence. A scan record showing companion faults and operating state can help determine which diagnostic path the actual service procedure requires.

The source contains a copied reference to sensor A inside its B-channel duty-cycle description; this article follows the P05DC heading and explicit B-signal criteria without transferring that inconsistent label into a pin-level instruction.

Monitoring can occur in running or shutdown software states. Brake-system testing requires appropriate professional methods. After the established repair, verify both credible travel and valid B-channel signaling as applicable, rather than relying on a stationary pedal reading or cleared memory.

Source and applicability

GM 2018 18OBDG02 Hybrid Diagnostics, BSC2 brake-system monitor table; document-level example only, vehicle/calibration fitment not established. The manufacturer service document is hosted by the manufacturer. Its diagnostic instructions take precedence over a general code dictionary.