P0D1A: Hybrid/EV Battery Pack Coolant Control Valve B Control Circuit/Open

P0D1A flags an open or otherwise faulty drive circuit of coolant control valve B, a second actuator in the coolant loop of the hybrid or EV battery. Which physical valve gets the letter B, and what it switches, is up to the vehicle maker. No manufacturer documents P0D1A in a public bulletin or OBD table. The best documented analogue is valve A: Mercedes battery management reports its actuation as faulty or interrupted (LI83.30-P-061224), and CARB requires every electronic output used for battery heating or cooling to be checked for circuit faults. A broken wire, a corroded plug or an open valve coil are the usual findings. With the valve unusable the pack may run too warm or too cold, so charging and power can be limited. Shorts to ground or voltage are P0D1D and P0D1E.

High severity. Can I keep driving?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.

Symptoms

Hybrid or EV system warning and MIL
Reduced charging or drive power because battery temperature cannot be managed

Most likely causes

Broken wire or corroded connector in the valve B drive circuit
Open coil or motor winding inside valve B
Faulty output stage in the controlling module

What to check, in order

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

Read the codes with a hybrid-compatible scanner and write down the freeze frame data
Check the continuity of the wire between the component and the control module.
Make sure the battery cooling air intake is clean
Check the 12 V auxiliary battery, which can also trigger warnings
Leave any high-voltage measurements to a specialized repair shop

Good to know

Repair difficulty: hard
It can trigger limp mode.
It affects emissions.

What each character of P0D1A means

P: Powertrain: engine and transmission
0: Generic code: same on every make
D: Subsystem depends on the code range
1A: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0D1A?

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 P0D1A?

The most common causes are: broken wire or corroded connector in the valve B drive circuit; open coil or motor winding inside valve B; faulty output stage in the controlling module.

Related codes

Sources

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.