Powertrain, generic · Hybrid propulsion

P0B36 High Voltage Service Disconnect Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B36 sets when the service disconnect detection signal stays above its upper limit. With a pulled-up input this usually means a short to a voltage source or a missing coding element in the plug; on some designs an open loop also reads high, so manufacturers separate it with P0B37 only where they can tell the cases apart. Patents from Ford and Lear show the detection loop as a low-voltage circuit that closes through the plug and is read by a battery or vehicle controller. No manufacturer documents P0B36 publicly. CARB requires such hybrid inputs to be monitored for out-of-range values. Low and performance faults are P0B35 and P0B34. The high-voltage system normally stays switched off.

Likely causes

Detection loop wire shorted to a supply voltage
Open loop or missing contact read as high signal
Wrong or damaged service disconnect plug without proper coding
Battery controller input stage fault

Symptoms

  • Vehicle not ready to drive
  • MIL and high-voltage warning on
  • Charging blocked

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–1,500
Time0.5–4 h

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

Parts involved

hv service disconnect switchwiring harnessbms

Related codes

P0B33P0B34P0B35P0B37P0A0D

References: law.cornell.edu, patents.google.com, patents.google.com.