P0DAD: Hybrid/EV Battery Cell Balancing Circuit A Stuck On

P0DAD means balancing circuit A keeps draining its cells although the controller has not asked for it: the bleed switch is stuck closed and the resistor keeps pulling those cells down. Ford uses the code in the BECM of its hybrids; the 2019 OBD summary gives each of 14 circuits six cells and, at key-on with the contactors still open, rates a circuit faulty when one of its cells departs from the mean for 0.1 s by over 75 mV. Toshiba's patent US20130026994A1 detects such a shorted balancing switch with a comparator. Left alone, the affected cells sink below the rest, particularly while the car is parked, and the usable pack window shrinks. Which cells form group A is up to the maker.

Symptoms

• Hybrid or EV battery warning with the MIL
• Cells of one group noticeably lower after the car has been parked
• Range or electric assistance decreasing over days

Most likely causes

• Balancing transistor of circuit A shorted (fails closed)
• Monitoring chip or its drive output keeps the switch enabled
• Controller software leaving a balancing request active

What to check, in order

Start with the simplest. You can tick off each step.

1. Read the codes with a hybrid-compatible scanner and write down the freeze frame data
2. Use the scanner to command the movement and compare the actual position with the requested one.
3. Make sure the battery cooling air intake is clean
4. Check the 12 V auxiliary battery, which can also trigger warnings
5. Leave any high-voltage measurements to a specialized repair shop

Good to know

• It can trigger limp mode.
• It affects emissions.

What each character of P0DAD means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• D: Subsystem depends on the code range
• AD: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0DAD?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code P0DAD?

The most common causes are: balancing transistor of circuit A shorted (fails closed); monitoring chip or its drive output keeps the switch enabled; controller software leaving a balancing request active.

Related codes

• P0DABHybrid/EV Battery Cell Balancing Performance
• P0DACHybrid/EV Battery Cell Balancing Circuit A
• P0DAEHybrid/EV Battery Cell Balancing Circuit A Stuck Off
• P0DAFHybrid/EV Battery Cell Balancing Circuit A Range/Performance
• P0DB1Hybrid/EV Battery Cell Balancing Circuit B Stuck On

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 13OBDG05C Hybrid Diagnostics
• patents.google.com: en
• fordservicecontent.com: OBDSM1901 HEV

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.