P0D9D: Battery Charger Coupler Temperature Sensor A Circuit Intermittent/Erratic

P0D9D is logged when the signal of temperature sensor A in the charging inlet jumps or drops out for short moments instead of failing for good. The sensor sits beside the power pins so the car can cut back or end charging once contact resistance heats them; TE Connectivity patents US10960781B2 and US11117478B2 name thermistors and resistance thermometers for this job. No manufacturer documents P0D9D publicly. A related smart case shows the pattern: with the 22 kW charger, Mercedes blamed inlet sensor codes on loose low-voltage plugs at the charger and warned that the fault may only show up with warm or cold parts. Typical is a session that stops for no clear reason and works again later. Steady circuit, plausibility, low and high faults are P0D99 to P0D9C.

Symptoms

• Charging stops now and then and resumes on a later attempt
• Charging power reduced for a while without an obvious reason
• Charging fault message that comes and goes

Most likely causes

• Sensor wiring between inlet and charger with a loose or chafed contact
• Low-voltage connector at the on-board charger not fully seated (seen on smart for sibling codes)
• Moisture or corrosion in the inlet harness connector
• Temperature element in the inlet with an internal intermittent break

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. Gently move the wiring with the engine running and watch whether the reading changes.
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

• Repair difficulty: medium

What each character of P0D9D means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• D: Subsystem depends on the code range
• 9D: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0D9D?

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 P0D9D?

The most common causes are: sensor wiring between inlet and charger with a loose or chafed contact; low-voltage connector at the on-board charger not fully seated (seen on smart for sibling codes); moisture or corrosion in the inlet harness connector.

Related codes

• P0D99Battery Charger Coupler Temperature Sensor A Circuit
• P0D9ABattery Charger Coupler Temperature Sensor A Circuit Range/Performance
• P0D9BBattery Charger Coupler Temperature Sensor A Circuit Low
• P0D9CBattery Charger Coupler Temperature Sensor A Circuit High
• P0E5FBattery Charger Coupler Temperature A Too High

Sources

• patents.google.com: en
• patents.google.com: en
• static.nhtsa.gov: MC 10144078 9999
• law.cornell.edu: 13 CCR 1968.2

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.