P0A80 Replace the hybrid battery

DTC P0a80 - OBD-II Data Sheet

Replace the hybrid battery

What does trouble code P0A80 mean?

This Generic Powertrain Diagnostic Trouble Code (DTC) is commonly applied to many OBD-II hybrid EVs. This may include but is not limited to Toyota vehicles (Prius, Camry), Lexus, Fisker, Ford, Hyundai, GM, etc.

A P0A80 code stored means the powertrain control module has detected a malfunction in the hybrid vehicle battery management system (HVBMS). This code indicates a weak cell failure has occurred in the hybrid battery.

Hybrid vehicles (which do not require external charging) use NiMH batteries. Battery packs are actually battery packs (modules) that are connected together using busbar or cable sections. A typical high voltage battery consists of eight cells connected in series (1.2 V). Twenty-eight modules make up a typical HV battery pack.

HVBMS regulates the charge level of the battery and monitors its condition. Cell resistance, battery voltage, and battery temperature are all factors that HVBMS and PCM take into account when determining battery health and desired charge level.

Multiple ammeter and temperature sensors are located at key points in the HV battery. In most cases, each cell is equipped with an ammeter / temperature sensor. These sensors provide HVBMS data from each cell. The HVBMS compares the individual voltage signals to determine if there are discrepancies and reacts accordingly. The HVBMS also provides the PCM via the Controller Area Network (CAN) with the battery charge level and battery pack status.

When the HVBMS provides the PCM with an input signal that reflects a battery or cell temperature and / or voltage (resistance) mismatch, a P0A80 code will be stored and the malfunction indicator light may illuminate.

An example of the location of the hybrid battery pack in a Toyota Prius:

What is the severity of this DTC?

The P0A80 code indicates a serious malfunction in a main component of the hybrid vehicle. This must be urgently resolved.

What are some symptoms of a P0A80 code?

Symptoms of a P0A80 trouble code may include:

• Reduced fuel efficiency
• Decreased overall performance
• Other codes related to high voltage battery
• Disconnection of the electric motor installation

What are some of the common causes for the code?

P0A80 will be present when the BMS (Battery Monitoring System) detects a voltage difference of 20% or more between battery packs. Typically, the presence of a code P0A80 means that one of the 28 modules has failed, and others will soon fail if the battery is not replaced or repaired properly. Some companies will only replace the failed module and send you on your way, but within a month or so there will be another failure. Simply replacing one faulty module is a temporary fix for what will be a constant headache, costing more time and money than simply replacing the entire battery. In this situation, all cells should be replaced with others that have been properly looped, tested, and have similar performance.

Why did my battery fail?

Aging NiMH batteries are subject to the so-called "memory effect". A memory effect can occur if a battery is charged repeatedly before all of its stored energy is used up. Hybrid vehicles are prone to shallow cycling because they typically stay between 40-80% charge levels. This surface cycle will eventually lead to the formation of dendrites. Dendrites are tiny crystal-like structures that grow on dividing plates inside cells and eventually block the flow of electrons. In addition to the memory effect, an aging battery can also develop internal resistance, causing the battery to overheat and cause abnormal voltage drops under load.

Reasons for this code may include:

• Defective high voltage battery, cell or battery pack
• HVBMS sensor malfunction
• Individual cell resistance is excessive
• Differences in voltage or temperature of elements
• HV Battery Fans Not Working Properly
• Loose, broken or corroded busbar connectors or cables

What are the P0A80 troubleshooting steps?

NOTE. The HV battery should only be serviced by qualified personnel.

If the HV in question has more than 100,000 miles on the odometer, suspect a defective HV battery.

If the vehicle has driven less than 100 miles, a loose or corroded connection is likely the cause of the failure. Repair or refurbishment of the HV battery pack is possible, but either option may not be reliable. The safest method of troubleshooting a HV battery pack is to replace the factory part. If it's prohibitively expensive for the situation, consider a used HV battery pack.

To diagnose the P0A80 code, you will need a diagnostic scanner, a digital volt / ohmmeter (DVOM), and a high voltage battery diagnostic source. Use the scanner to monitor HV battery charging data after obtaining test procedures and specifications from HV motor information source. Component layouts, wiring diagrams, connector faces, and connector pinouts will aid in accurate diagnosis.

Visually inspect the HV battery and all circuits for corrosion or open circuits. Remove corrosion and repair defective components if necessary.

After retrieving all stored codes and the corresponding freeze frame data (connect the scanner to the vehicle's diagnostic port), clear the codes and test drive the vehicle to see if P0A80 is reset. Test drive the vehicle until the PCM enters readiness mode or the code is cleared. If the code is cleared, use the scanner to identify which HV battery cells are mismatched. Write down the cells and continue with the diagnosis.

Using freeze frame data (from the scanner), determine if the condition that caused the P0A80 persist is an open circuit, high cell / circuit resistance, or a HV battery pack temperature mismatch. Verify the appropriate HVBMS (temperature and voltage) sensors following the manufacturer's specifications and test procedures. Replace sensors that do not meet manufacturer's specifications.

You can test individual cells for resistance using the DVOM. If individual cells show an acceptable degree of resistance, use the DVOM to test resistance in bus connectors and cables. Individual cells and batteries can be replaced, but a complete HV battery replacement may be the most reliable solution.

• A stored P0A80 code does not automatically deactivate the HV battery charging system, but the conditions that caused the code to be stored may disable it.

P0A80 Replace Hybrid Battery Pack Causes and Solutions Explained in Urdu Hindi

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NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.