P0C24 – Drive Motor “B” Control Module

P0C24 is a hybrid/EV trouble code that usually points to a problem in the high-voltage battery or its monitoring circuit, not a simple 12-volt issue. When this code sets, your car’s control module has seen something out of range in the battery’s internal sensors or wiring. You might notice warning lights, reduced performance, or the car refusing to go into READY mode. In this guide, you’ll learn what P0C24 means in plain language, common symptoms, likely causes, how a mechanic diagnoses it, and what repairs and costs you can expect.

What Does P0C24 Mean?

P0C24 is a generic OBD-II hybrid/EV code that typically translates to a high-voltage battery or battery sensor circuit fault. Exact wording varies by manufacturer, but it usually refers to a problem with one of the battery’s internal voltage or temperature sensing circuits being out of its expected range.

The hybrid/EV control module (sometimes called the battery ECU or HV ECU) constantly monitors individual battery modules. If it sees abnormal voltage, resistance, or temperature data from a specific sensor or section, it stores P0C24 and may limit power to protect the battery pack. This is more than a nuisance light—left alone, it can lead to serious battery damage.

Quick Reference

• Code: P0C24
• Type: Hybrid/EV high-voltage battery or sensor circuit fault
• Urgency: Moderate to high – diagnose soon to prevent battery damage
• Typical Symptoms: Warning lights, reduced power, no READY, poor fuel economy
• Common Culprits: Battery sense wiring, corroded connectors, failing battery module, bad battery ECU

Real-World Example / Field Notes

In the shop, I usually see P0C24 on older hybrids or EVs with some mileage and age on the battery pack. A typical case: a customer complains that the hybrid warning light and check engine light came on, and the car feels sluggish. Scan data shows P0C24 plus a few related high-voltage battery codes. After pulling the battery cover, I’ll often find corroded sense connectors or a weak module in one section of the pack. Cleaning and repairing the harness fixes some cars; others need a module or full pack replacement.

Symptoms of P0C24

• Warning lights – Hybrid system warning, check engine light, or EV system malfunction indicator illuminated.
• Reduced power – Noticeable loss of acceleration, especially under heavy load or at highway speeds.
• No READY mode – In some cases, the vehicle refuses to go into READY or drive mode to protect the battery.
• Engine runs more – On hybrids, the gasoline engine stays on longer and assists more often than normal.
• Poor fuel economy – Drop in MPG as the hybrid system reduces or disables electric assist.
• Battery fan noise – High-voltage battery cooling fan running frequently or at high speed.
• Intermittent behavior – Code and symptoms may come and go with temperature, bumps, or humidity.

Common Causes of P0C24

Most Common Causes

• Corroded or loose battery sense connectors – Moisture or age can corrode the small voltage sense terminals on the battery pack, causing erratic readings.
• Damaged sense wiring harness – Broken, pinched, or shorted wires between the battery modules and the battery ECU.
• Failing high-voltage battery module – One or more modules inside the pack drifting out of spec under load or temperature.
• Battery ECU internal fault – The control module that reads the battery sensors can fail or develop bad internal solder joints.
• Poor ground or power supply – Weak grounds or low reference voltage to the battery ECU causing inaccurate sensor readings.

Less Common Causes

• Previous improper repairs – Incorrectly reassembled battery packs, missing insulators, or non-OEM modules causing imbalance.
• Water intrusion – Leaks into the battery compartment or harness connectors leading to intermittent shorts.
• Connector pin damage – Bent, pushed-out, or spread terminals at the battery ECU or junction blocks.
• Software calibration issues – Rare, but some vehicles require a control module update to correctly interpret battery sensor data.
• Severe overheat events – Past overheating of the battery pack altering sensor characteristics or damaging modules.

Diagnosis: Step-by-Step Guide

You’ll want at least a quality scan tool capable of reading hybrid/EV data, a digital multimeter, basic hand tools, and proper high-voltage safety gear. If you’re not trained on high-voltage systems, it’s best to leave anything beyond basic checks to a professional; the battery pack can be dangerous if mishandled.

1. Confirm the code and check for companions – Use a scan tool to read all stored DTCs. Note any other high-voltage battery or hybrid system codes that appear with P0C24.
2. Check freeze frame and live data – Look at when P0C24 set: temperature, state of charge, speed, and load. Review individual battery block voltages and temperatures to see if one section looks out of line.
3. Inspect 12V system first – Verify the 12-volt battery and charging system are healthy. Low 12V voltage can cause strange hybrid behavior and misleading codes.
4. Visually inspect battery compartment – With the vehicle powered down and made safe, inspect the battery area for water intrusion, corrosion, or obvious damage to harnesses and connectors.
5. Check sense harness and connectors – Carefully inspect the voltage sense wiring and plugs going to the battery ECU. Look for green corrosion, broken insulation, or loose terminals.
6. Measure suspect circuits – Following factory service information, use a multimeter to check continuity, resistance, and, when safe and specified, voltage on the affected sensor circuits.
7. Compare block voltages – Using scan data or manufacturer test procedures, compare each battery block’s voltage. A weak or out-of-range block often points to a failing module.
8. Check Mode $06 and test results – On some vehicles, Mode $06 or special hybrid tests will show which block or sensor is failing its self-test, helping you pinpoint the problem.
9. Evaluate the battery ECU – If wiring and modules check out but readings remain erratic, follow OEM tests to confirm whether the battery ECU is faulty.
10. Clear codes and road test – After repairs, clear P0C24 and perform a controlled road test while monitoring live data to ensure the code does not return.

Pro tip: Always follow the manufacturer’s high-voltage disable procedure before opening or disconnecting anything on the battery pack. Skipping this step can lead to serious injury and expensive damage.

Possible Fixes & Repair Costs

Repairs for P0C24 range from simple connector work to full battery replacement. Cleaning and tightening corroded sense connectors or repairing a damaged harness can be relatively inexpensive, often in the $150–$450 range depending on labor time. Replacing a failing battery module or reconditioning a pack can run $600–$1,500. A complete new high-voltage battery pack can cost $2,000–$5,000+ installed, depending on the vehicle. Factors that affect cost include vehicle make, parts availability, whether you choose new vs. reman battery components, and local labor rates.

Can I Still Drive With P0C24?

In many cases, you can still drive with P0C24, but the vehicle may limit power or rely more heavily on the gasoline engine. Short trips to a repair shop are usually fine if the car still goes into READY mode and drives normally. However, if you notice severe power loss, unusual noises, strong battery fan operation, or additional warning messages like “Stop Safely,” you should avoid driving and have the car towed. Continuing to drive with an active high-voltage battery fault increases the risk of overheating and permanent battery damage.

What Happens If You Ignore P0C24?

Ignoring P0C24 can turn a minor wiring or sensor issue into a major battery failure. The control module may keep stressing a weak module, leading to overheating, further imbalance, and eventually a pack that can’t be repaired with simple module replacement. You could end up needing a full high-voltage battery instead of a much cheaper harness or connector repair.

Last updated: January 22, 2026

Vehicles Commonly Affected by P0C24

P0C24 shows up most often on older hybrids and early EVs as the battery packs age. You’ll commonly see it on Toyota and Lexus hybrids (Prius, Camry Hybrid, Highlander Hybrid, RX), Honda hybrids (Civic Hybrid, Insight, Accord Hybrid), and some Ford and GM hybrid models. Certain Nissan and Mitsubishi EVs and plug-in hybrids can also log this code. Any high-mileage hybrid or EV that has seen heat, heavy use, or water leaks around the battery compartment is more likely to develop P0C24 or related battery sensor codes.