DTC P1AC0-00: Hybrid/EV Battery Cell Low Voltage [12/2019 - 11/2023]: Description

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The hybrid vehicle control ECU controls the SOC (state of charge) of the HV battery at a constant level during driving. The HV battery is composed of 40 modules, and each module consists of six 1.2 V cells in series. The battery voltage sensor monitors battery block voltage at 12 locations.

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DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Warning Indicate
P1AC0-00	Hybrid/EV Battery Cell Low Voltage	Voltage difference between battery blocks is larger than the specified value due to an internal malfunction of the HV battery. (2 trip detection logic)	Battery voltage sensor HV battery Hybrid battery terminal block	Comes on	Master Warning: Comes on

RELATED DATA LIST

DTC No.	Data List
P1AC0-00	Hybrid Battery Block 1 to 12 Voltage*1 Hybrid Battery SOC

HINT:

*1: Under normal conditions, the values of Hybrid Battery Block 1, 2, 11 and 12 Voltage will be approximately 16 V and Hybrid Battery Block 3, 4, 5, 6, 7, 8, 9 and 10 Voltage will be approximately 32 V.
If there is a short or open in a battery block voltage detection line, the value of Hybrid Battery Block Voltage for the corresponding battery block will be lower than 8 V.

The following items can be helpful when performing repairs:

Data List

Internal Resistance 1 to 12
Ready Signal
Vehicle Speed
Accelerator Position
Shift Position
Engine Speed
Hybrid Battery Voltage
Hybrid Battery Current
BATT Voltage
Hybrid Battery SOC of Immediately after IG ON
Hybrid Battery Maximum SOC
Hybrid Battery Minimum SOC
Total Distance Traveled
Distance from DTC Cleared
Engine Run Time

Vehicle Control History Data

Hybrid Battery Voltage Low

HINT:

This DTC can be stored after clearing DTCs and driving the vehicle for approximately 10 minutes. (As 2 trip detection logic is used, check for DTCs including pending DTCs.)
DTC P1AC0-00 is stored when a malfunction is detected in the HV battery or battery voltage sensor. If the HV battery is malfunctioning, the malfunction may not be reproduced when the condition of the HV battery changes due to a difference in driving load (amperage), SOC and battery temperature. Therefore, use the Freeze Frame Data when performing a repair.
1. When the HV battery is malfunctioning:
  1. - Voltage of 1 or few battery blocks has dropped. The difference of voltage value between the hybrid battery block 1 and 2, 3 and 4, 4 and 5, 5 and 6, 6 and 7, 7 and 8, 8 and 9, 9 and 10 or 11 and 12 is 1.2 V or more.
  2. - Voltage of all battery blocks is output randomly with no certain pattern.
2. When the battery voltage sensor is malfunctioning:
  1. - Differences in battery block voltages have a certain pattern.
In order to ensure HV battery performance, appropriate cooling performance must be maintained. Perform the following items as necessary. If cooling performance has decreased and "Maintenance Required for Traction Battery Cooling Parts See Owner's Manual" is displayed on the multi-information display, make sure to perform the following items:
- Make sure the air intake port is not blocked.
- Make sure there are no gaps between the connecting parts of the ducts.
- Clean the No. 2 HV battery intake filter (LH side and RH side).
  1. Clear the DTCs to reset the learning values even if no DTCs are stored.