Powertrain, generic (extended)

P2AD5 Intermediate System Voltage High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2AD5 is the high counterpart: the intermediate voltage level, in current vehicles mostly a 48 V mild-hybrid network, rises above its permitted maximum. Overvoltage typically arises when the starter-generator regenerates harder than the battery can accept, for example with a full or cold 48 V battery, a battery that has disconnected itself internally, or a faulty regulator in the generator or DC/DC converter. No manufacturer publishes P2AD5 or its threshold, so the details are maker specific; the assignment to 48 V follows from the term and the spread of such networks since 2018. Connected modules may switch off to protect themselves, so recuperation, electric boost and start-stop drop out and the 12 V side may show warnings. Diagnosis starts with the battery management data and the charge command of the generator.

Likely causes

Starter-generator regulating the voltage too high
48 V battery disconnected internally or unable to accept charge
Faulty DC/DC converter feeding back into the network

Symptoms

  • Warning message about the electrical system
  • Recuperation, electric boost and start-stop unavailable

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–2,500
Time1–6 h

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

Parts involved

starter generatordc dc converterwiring harness

Related codes

P2AD4P0563P0A94

References: law.cornell.edu, en.wikipedia.org.