P0B70

Code

Generic P — Powertrain

Hybrid/EV Battery Voltage Sense K Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 31 EN: 35 RU: 26

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Page language: EN

Causes

Open or short in the battery voltage sense K wiring harness
Corroded, loose, or damaged connector at the HV battery or control module
Failed voltage divider or sensing resistor network (in battery pack or module)
Faulty Battery Management System (BMS) / hybrid control module input
Short to battery positive (HV) on the sense lead
Poor ground or reference voltage problem

Symptoms

Malfunction Indicator Lamp (MIL) or hybrid warning lamp illuminated
Reduced engine/drive performance or limp mode
Charging or regenerative braking disabled or limited
Inaccurate state-of-charge or battery pack voltage readings on scan tool
Vehicle may refuse to enter ready/drive, or charging may be inhibited

What to check

Read DTC and freeze frame data with a capable scan tool; record stored/active codes and conditions
Review manufacturer service data for the voltage sense K circuit location and expected thresholds
Visually inspect HV battery pack area, connectors and wiring for damage, corrosion, or water ingress (adhere to HV safety procedures)
Confirm connector pins are fully seated and locking tangs intact at battery and control module
Using HV‑rated test equipment and with the HV system made safe per procedures, measure the voltage at the battery pack sense K terminal and at the control module sense pin
Check continuity and resistance of the sense circuit (with HV isolated) to detect opens/shorts to pack positive or ground

Signal parameters

Depends on vehicle — high voltage battery pack nominally hundreds of volts; sense circuit is usually stepped down to a low‑voltage ADC input (typical: 0–5.0 V)
Expected ADC/sense voltage: within manufacturer tolerance, commonly 0–4.9 V; a 'High' DTC typically triggers when sense > threshold (example: >4.9 V)
Open‑circuit behavior: ADC may float to a rail or pull‑up, appearing as an over‑range (near Vref rail)
Recommended instruments: HV‑rated digital multimeter for DC volts, and an oscilloscope for transient checks; use insulated leads and PPE

Diagnostic algorithm

Record DTC(s), freeze frame, and active/inactive status with a compatible scan tool. Check for related hybrid/BMS codes.
Follow vehicle manufacturer HV safety procedure: de‑energize/high‑voltage isolate the HV system before touching harness or connectors.
Perform a careful visual inspection of the sense K wiring harness, routing, insulation, and all connectors for heat damage, corrosion, water ingress or mechanical damage.
With HV isolated, check continuity and resistance between the sense K pin at the control module and the corresponding pin at the battery pack. Expect low resistance through the sense wiring; an open indicates broken wiring or connector.
Check for unintended shorts: measure resistance from the sense line to HV+ and to chassis ground. A short to HV+ will show very low resistance; a short to ground likewise.
Re‑energize HV (only if manufacturer allows and after safety checks). Backprobe the control module’s sense K pin and measure the voltage relative to module ground with an HV‑rated DMM. Compare to the manufacturer specified voltage and to the battery pack sense voltage (at the pack sense connector).
If the sense line reads near the supply rail or above specified threshold, trace wiring for a short to battery positive or a failed pull‑up resistor. If the pack side reads normal but module side is high, suspect harness/connector or module input fault.
If wiring and connectors are good but voltages remain out of range, test or replace the pack sensing module/voltage divider assembly per service manual. If pack sensor OK, suspect control module input circuitry and consult OEM guidance for module testing/repair.
After repairs, clear codes, perform functional tests and a road/charge cycle to verify the fault does not return.
If intermittent, inspect for conditions that change with temperature or vibration; use wiggle test and monitoring with live data while cycling conditions.

Likely causes

Damaged insulation allowing contact with HV+ conductor near sense lead
Connector pin pushed out or corroded at battery pack sense connector
Internal failure of the pack’s voltage sensing board (open or changed resistor values)
Shorted sense line to a high potential through damaged wiring
Failed hybrid/inverter control module ADC input circuitry

Fault status

⚠️ Status

Hybrid/EV battery voltage sense K circuit — detected voltage higher than expected (sense input over‑range). Possible open/short or failed sensing component.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours