P0D18 code meaning
Battery Charging System A High Voltage Interlock Circuit High
Powertrain system Generic code P0Dxx codes Check engine light
What P0D18 means
P0D18 flags a charging HVIL signal that sits too high. On the Chevrolet Volt and Cadillac ELR GM tests the loop in two states: with the 5 V source off, a sensed level above 24 % of reference (5 of 6 samples in 2011, 5 of 8 for 2014 and ELR), and with it on, a level above 44 % (4 of 6), set the code as Type A, MIL after one trip. A high value may point to a break or added resistance in the loop or a short to a voltage. Polestar stores P0D1800 in the BECM of the 2021–2023 Polestar 2 with a propulsion warning and resolves it with BECM software 2.10 (TJ 36713). Kia lists P0D1812 for the 2023 Niro EV among the codes that lead to ICCU replacement (bulletin 298). The low case is P0D17, the open loop P0D15.
P0D18 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0D18
- Malfunction indicator lamp (GM Type A)
- Propulsion or high-voltage warning in the cluster
- Slow or no AC charging
Common causes of P0D18
- PossibleHigh resistance or partial break in the interlock loop
- PossibleBattery module software needing an update (Polestar 2)
- PossibleFaulty integrated charging unit (Kia Niro EV ICCU)
- Less likelyInterlock wire shorted to a voltage source
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Bcs a hv interlockWiring harnessOn board chargerHybrid control module
What each part of P0D18 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 18 | The exact fault in that area. |
What to do next
- Note P0D18 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0D18
What does P0D18 mean?
P0D18 means "Battery Charging System A High Voltage Interlock Circuit High". P0D18 flags a charging HVIL signal that sits too high. It is a generic code, so it means the same on every make.
Is it safe to drive with P0D18?
Drive gently and only to a workshop. With P0D18 the car can go into limp mode (reduced power) to protect itself.
Will P0D18 fail an emissions test?
P0D18 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P0D18 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 5 hours of work. This is a job for a workshop.
Will P0D18 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.