Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P05E4 Park Brake Sensor/Switch Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

The engine module reads the park brake status, directly or via another module, because strategies depend on it: a parked diesel filter regeneration only runs with the park brake applied (Navistar), idle shutdown and PTO logic use it, and Ford delays an automatic restart while the electric park brake moves. CARB requires such inputs to be monitored. The only documented user of this code family is Volvo Trucks: since OBD 2021 a second park brake sensor (about 0.5 V applied, 3.5 V released) must agree with the old switch; the engine module reports the fault. No passenger car maker uses it verifiably. P05E4 means the signal is below the lower limit: on a three-wire sensor a signal shorted to ground or a missing 5 V supply; on a simple ground switch it looks like a permanently applied brake.

Likely causes

Signal wire shorted to ground (chafed)
Sensor 5 V supply missing or shorted to ground
Sensor faulty internally
Module input faulty

Symptoms

  • Check engine light or OBD warning (heavy-duty)
  • Park brake warning in the cluster
  • Parked regeneration cannot be started
  • Stop-start or idle shutdown not working

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–300
Time0.5–2 h

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

Parts involved

park brake switchpark brake sensorsensor wiring

Related codes

P05E3P05E5P05E6P05E7

References: law.cornell.edu, static.nhtsa.gov, static.nhtsa.gov.