P0CBA: Hybrid/EV Battery Temperature Sensor P Circuit High

What it means

The HV battery temperature sensor P reports a circuit high fault. Cell-group temperature monitoring impaired on this channel.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Sensor P reports the temperature of a section of the high-voltage battery to the battery control module. This code sets when the Sensor P signal rises above its permitted range, often because the signal wire is shorted to battery positive or the sensor circuit is open.

Common causes

Most likely first.

1. Signal wire shorted to B+
2. Open sensor
3. Connector pins corroded - high contact resistance

Symptoms

• EV/hybrid system warning light on
• Reduced power output or limp mode
• Charging may fail or be slowed
• Reduced electric range

How to diagnose it

1. Record freeze-frame data and compare Sensor P’s live reading with adjacent battery temperature sensors for an implausibly high or fixed value.
2. Shut the vehicle down using the manufacturer’s high-voltage safety procedure, then inspect Sensor P’s connector and harness for corrosion, loose pins, and insulation damage.
3. Check the Sensor P signal wire for a short to B+ and for an open circuit using the vehicle wiring information.
4. Test terminal contact and circuit continuity, paying attention to corrosion that may interrupt the connection.
5. If the circuit checks out, test Sensor P against the manufacturer’s specification and replace it if open or out of range.

Common fixes

• Reseat Sensor P’s connector and clean or repair corroded terminals.
• Repair the Sensor P signal wire shorted to B+ or the open wiring section.
• Replace Sensor P if it fails the manufacturer’s test.

Can I keep driving?

Charging or electric power may be restricted while Sensor P’s battery section temperature is unavailable. Avoid long trips if the warning or reduced-power mode is active, and stop safely if power drops sharply.