Network, generic (extended)

U3502 Control Module Input Power A Circuit High

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

U3502 means supply A rises above its allowed limit. In GM's 2016–2019 hybrid OBD tables the electric brake booster checks its CAN supply voltage and sets U3502 above 16 V lasting 0.09 s while its software runs; this is Type B, so the MIL comes on after two failing trips, and the test passes after 30 s with ignition on. Unlike low voltage, which a module can often ride out, overvoltage endangers electronics and power stages, which explains the short reaction time. Common causes are a regulator fault in the generator or DC/DC converter, jump-starting from a 24 V source or a wrongly set charger, and a load dump when a battery cable comes loose while charging. If several modules report high voltage at the same moment, the charging system is at fault, not the module.

Likely causes

Generator regulator or DC/DC converter overcharging
Jump start or external charger with excessive voltage
Loose battery terminal causing voltage spikes
Faulty voltage measurement inside the module

Symptoms

  • MIL after repeated trips
  • Several modules logging overvoltage at once
  • Flickering lights or battery warning

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–700
Time0.3–2.5 h

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

Parts involved

module power acharging system

Related codes

U3501U3500U3503U3506U350A

References: gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.