Powertrain, generic · Hybrid propulsion

P0B49 Hybrid/EV Battery Voltage Sense C Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B49 is reserved for a channel C signal that jumps or drops out briefly instead of failing for good. No manufacturer documents this code publicly; GM, which uses the other four channel C codes, has no erratic test for it in its published tables. A technician would start from the freeze frame and log cell voltage C next to its neighbours while flexing the module harness, because a loose crimp or a cracked solder joint on the monitoring board shows up as spikes that a permanent test misses. CARB requires battery voltage sensors of the energy storage system to be monitored like any input and faults to be tied to the smallest replaceable unit. Warnings may come and go.

Likely causes

Loose crimp or connector on the channel C sense line
Cracked solder joint on the cell monitoring board
Electrical noise from the inverter coupling into the sense line

Symptoms

  • Warning light that appears and disappears
  • Occasional short loss of electric drive power

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–6,000
Time0.5–8 h

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

Parts involved

hv battery voltage sense cwiring harnessbms

Related codes

P0B45P0B46P0B47P0B48P0B44P0B4E

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