P0B47

Code

Generic P — Powertrain

Hybrid/EV Battery Voltage Sense C Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 26 EN: 41 RU: 31

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Page language: EN

Causes

Open or shorted wiring in the voltage-sense C circuit
Poor or corroded connector or terminal at the sense harness or battery junction
Faulty battery pack voltage sensor or sensing module (BMS submodule)
Faulty vehicle control module (ECU) input or internal circuitry
Blown fuse or power/ground issue affecting the sensing circuit
Intermittent harness damage (chafing, pinched, water ingress)

Symptoms

Malfunction Indicator Lamp (MIL) or Hybrid System warning illuminated
Hybrid system derate, reduced performance, or driveability limitations
Possible failure to start or inability to go into READY state
Incorrect or no pack voltage reading in scan tool data
Charging or regeneration disabled or limited

What to check

Retrieve freeze frame and live data with a scan tool: confirm sensed pack voltage C value and compare to actual pack voltage
Inspect wiring harness and connectors between battery pack (BMS) and vehicle control module for damage, corrosion, or loose pins
Verify related fuses, service plugs, and power/ground connections are intact
Check for other hybrid/EV codes that may point to BMS or CAN communication faults
Visually inspect battery junctions, voltage taps, and any external sensing modules for water intrusion or physical damage

Signal parameters

Sense circuit is typically a low-voltage signal to the ECU proportional to pack voltage (manufacturer dependent, commonly 0–5 V signal range)
Expected live-data value should track the actual HV battery pack voltage (e.g., if pack ≈200 V, the sense signal will be a scaled representation — consult vehicle service data for scaling)
Low-fault threshold: sensing voltage below manufacturer threshold (commonly
Open-circuit usually shows near 0 V; short-to-ground will also show near 0 V; short-to-Vref or supply will show high

Diagnostic algorithm

Use a compatible scan tool to confirm P0B47 and note any related DTCs or freeze-frame data. Record the sensed voltage C value and actual pack voltage.
With vehicle made safe per manufacturer HV procedures, visually inspect the high-voltage battery area, voltage tap connectors, harness routing, and protective shielding for damage or corrosion.
Check fuses and service disconnects for the BMS/sensor supply and replace if open. Verify proper power and ground at the BMS and ECU ground points.
Back-probe or measure the voltage-sense C signal at the ECU and at the battery-side connector (follow HV isolation rules). Confirm presence and expected voltage level while the system is in the correct state (per service manual).
If the sense line is low at the ECU but correct at the BMS, inspect continuity and resistance of the harness between them; repair any open/high resistance or short to ground.
If the sense line is low at the BMS connector, inspect the BMS sensing hardware, sense tap connections on the battery modules, and any voltage-divider components. Replace or repair BMS components as specified by manufacturer procedures.
Verify CAN/communication is healthy; sometimes the PCM/ECU interprets missing communication as a sensor fault—check for communication errors.
After repairs, clear codes and perform functional tests and drive cycle per service procedure. Monitor live data to ensure the sensed voltage tracks actual pack voltage under various states (idle, charge, load).
If fault persists after wiring and BMS checks, consider ECU input circuit fault and refer to manufacturer guidance for ECU bench testing or replacement.

Likely causes

Disconnected or loose connector at the battery pack voltage-sense C tap
Broken conductor or high-resistance connection between sensing point and ECU
Short to ground on the sense lead pulling the voltage low
Failed/resistor network or measurement circuit in the battery management module (BMS)
Damaged or corroded ground common for the sensing circuit
Fuse related to the BMS/voltage sense supply open

Fault status

⚠️ Status

Hybrid/EV battery pack voltage sense C circuit reports low (below threshold) or open condition; may cause hybrid system derate or disable.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.5-4 hours

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