P05DD: Brake Pedal Position Sensor B Circuit Low

What does P05DD mean?

Brake-by-wire and hybrid systems use a dual-channel pedal travel sensor; channel B runs opposite to A at Toyota (3.6–4.4 V at rest, falling when pressed), so a common fault of both channels shows up. It feeds brake assist and regenerative blending; CARB requires inputs used by other diagnoses to be monitored. A channel fault blocks the A/B correlation P05E0 and usually limits brake assist or regeneration. P05DD means channel B is below its valid range – signal or shared 5 V reference shorted to ground (then sensor A reports as well). Mitsubishi's 2022 Outlander PHEV sets it with the regeneration warning light and the check engine light; for channel A it uses below 0.2 V for 0.5 s.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Brake or regeneration warning light
• Check engine light
• Regeneration or brake assist reduced, pedal feel changed

Common causes

• High Signal line B shorted to ground (harness at the pedal box)
• Medium 5 V reference shorted to ground (also sensor A code)
• Medium Pedal sensor faulty
• Low Brake or hybrid module

Likelihood is a general estimate across vehicles; your make and model may differ.