P0A84 Low Hybrid Battery Pack 1 Cooling Fan Control Circuit

P0A84 Possible Causes

  • Faulty battery cooling fan assembly
  • Open or short circuit in battery cooling fan assembly wiring harness
  • Poor electrical connection in battery cooling fan assembly circuit
  • Faulty relay
  • Faulty battery control unit
  • Powertrain control module (PCM)

What Does It Mean?

How to Fix Code P0A84

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0A84 Possible Symptoms

Check engine light illuminated (or service engine soon warning light)
P0A84 Meaning
Cooling air flows into the intake on the right side of the rear seat and moves through an intake duct to the battery blower on the right surface of the luggage compartment. Additionally, cooling air passes through an intake duct (which connects the battery blower assembly to the upper right surface of the HV battery assembly) and flows toward the HV battery assembly.
Cooling air flows from top to bottom between the HV battery modules. Once it has cooled the modules, it is discharged from the lower right surface of the HV battery assembly.
The discharged air passes through an exhaust duct on the right surface of the luggage compartment and is vented into the cabin as well as outside the vehicle.
The battery computer uses battery temperature sensors to detect the temperature of the HV battery assembly. Based on the results of this detection, the battery ECU controls the battery fan assembly. (Thus, the battery blower assembly starts when the HV battery temperature reaches a predetermined level.)

The speed of the battery cooling fan assembly is controlled by the powertrain control module. Power to the battery cooling fan assembly is supplied when the FCTL terminal of the powertrain control module activates the battery fan relay. The powertrain control module sends control signals (SI) to the battery cooling fan assembly to achieve the fan speed corresponding to the HV battery temperature. Information about the voltage applied to the battery cooling fan assembly (VM) is sent to the powertrain control module as a monitor signal using serial communication via the
OBDII Code P0A84 – Hybrid Battery Pack Cooling Fan 1 Control Circuit Low

P0A85 High Value of Hybrid Battery Pack Cooling Fan 1 Control Circuit

P0A85 Possible Causes

  • Faulty battery cooling fan assembly
  • Open or short circuit in battery cooling fan assembly wiring harness
  • Poor electrical connection in battery cooling fan assembly circuit
  • Faulty relay
  • Faulty battery intelligent unit
  • Faulty power management control ECU

What Does It Mean?

How to Fix Code P0A85

Check the “Possible Causes” listed above. Visually inspect the wiring harness and related connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0A85 Possible Symptoms

Check engine light illuminated (or service engine soon warning light)

P0A85 Meaning

Cooling air flows into the intake at the right side of the rear seat and moves through an intake duct to the battery blower on the right surface of the luggage compartment. Additionally, cooling air passes through an intake duct (which connects the battery blower assembly to the upper right surface of the HV battery assembly) and flows toward the HV battery assembly.
Cooling air circulates from top to bottom between the HV battery modules. Once it has cooled the modules, it is discharged from the lower right surface of the HV battery assembly.
The exhausted air passes through an exhaust duct on the right surface of the luggage compartment and is discharged into the cabin as well as outside the vehicle.

The battery computer uses battery temperature sensors to detect the temperature of the HV battery assembly. Based on the results of this detection, the battery ECU controls the battery fan assembly. (Thus, the battery blower assembly starts when the HV battery temperature reaches a predetermined level.)

The speed of the battery cooling fan assembly is controlled by the power management control ECU. Power to the battery cooling fan assembly is supplied when the FCTL terminal of the power management control ECU activates the battery fan relay. The power management control ECU sends control signals (SI) to the battery cooling fan assembly to achieve the fan speed corresponding to the HV battery temperature. Information about the voltage applied to the battery cooling fan assembly (VM) is sent to the power management control ECU as a monitor signal using serial communication via OBDII Code P0A85 – Hybrid Battery Pack Cooling Fan Control Circuit High

14 Volt Power Supply Module Current Sensor Circuit

P0A86 Possible Causes

Faulty 14-volt power module current sensor
14-volt power module current sensor harness is open or shorted
Poor electrical connection in 14-volt power module current sensor circuit

What Does It Mean?

How to Fix Code P0A86

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0A86

Symptoms

Possible

Check Engine Light illuminated (or Service Engine Soon warning light)

P0A86 Meaning

The Engine Control Module (ECM) monitors the 14-volt power module current sensor. The ECM sets the OBDII code when the 14-volt power module current sensor does not meet factory specifications.
OBDII Code P0A86 – 14-Volt Power Module Current Sensor Circuit

P0A87 14 Volt Power Supply Module Current Sensor Circuit Range / Performance

P0A87 Possible Causes

  • Faulty 14-volt power module current sensor
  • 14-volt power module current sensor harness is open or shorted
  • Poor electrical connection in 14-volt power module current sensor circuit

What Does It Mean?

How to Fix Code P0A87

Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, ejected, or corroded connector pins.

P0A87 Possible Symptoms

Engine light on (or service engine soon warning light)

P0A87 Meaning

The engine control module (ECM) monitors the 14-volt power module current sensor. The ECM sets the OBDII code when the 14-volt power module current sensor does not meet factory specifications.
OBDII Code P0A87 – 14-volt power module current sensor circuit range/performance

P0A88 Low Voltage 14 Volt Power Supply Module Current Sensor Circuit

P0A88 Possible Causes

  • Faulty 14-volt power module current sensor
  • 14-volt power module current sensor harness is open or shorted
  • Poor electrical connection in the 14-volt power module current sensor circuit

What Does It Mean?

How to Fix Code P0A88

Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0A88 Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P0A88 Meaning

The engine control module (ECM) monitors the 14-volt power module current sensor. The ECM sets the OBDII code when the 14-volt power module current sensor does not meet factory specifications.
OBDII Code P0A88 – 14-volt Power Module Current Sensor Circuit Low

P0A89 High 14 Volt Power Module Current Sensor Circuit

P0A89 Possible Causes

  • Faulty 14-volt power module current sensor
  • 14-volt power module current sensor harness is open or shorted
  • Poor electrical connection in 14-volt power module current sensor circuit

What Does It Mean?

How to Fix Code P0A89

Check the “possible causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, ejected, or corroded connector pins.

P0A89 Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P0A89 Meaning

The engine control module (ECM) monitors the 14-volt power module current sensor. The ECM sets the OBDII code when the 14-volt power module current sensor does not meet factory specifications.
OBDII Code P0A89 – 14-volt Power Module Current Sensor Circuit High

P0A8A 14 Volt Power Module Current Sensor Circuit Intermittent

P0A8A Possible Causes

  • Faulty 14-volt power module current sensor
  • 14-volt power module current sensor harness is open or shorted
  • Poor electrical connection in 14-volt power module current sensor circuit

What Does It Mean?

How to Fix Code P0A8A

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, ejected, or corroded connector pins.

P0A8A Possible Symptoms

Engine light on (or service engine soon warning light)

P0A8A Meaning

The Engine Control Module (ECM) monitors the 14-volt power module current sensor. The ECM sets the OBDII code when the 14-volt power module current sensor does not meet factory specifications.

P0A8B 14-Volt Power Module System Voltage

P0A8B Possible Causes

  • Faulty 14-volt power module
  • 14-volt power module harness is open or shorted
  • Poor electrical connection in 14-volt power module circuit

What Does It Mean?

How to Fix Code P0A8B

Check the “possible causes” listed above. Visually inspect the related cable harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

P0A8B Possible Symptoms

Engine light on (or service engine soon warning light)

P0A8B Meaning

The Engine Control Module (ECM) monitors the 14-volt power module. The ECM sets the OBDII code when the 14-volt power module does not meet factory specifications.

P0A8C 14 Volt Power Supply Module System Voltage Unstable

P0A8C Possible Causes

  • Faulty 14-volt power supply module
  • 14-volt power supply module harness is open or shorted
  • Poor electrical connection in the 14-volt power supply module circuit

What Does It Mean?

How to Fix Code P0A8C

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

P0A8C Possible Symptoms

Engine light on (or service engine soon warning light)

P0A8C Meaning

The Engine Control Module (ECM) monitors the 14-volt power supply module. The ECM sets the OBDII code when the 14-volt power supply module does not meet factory specifications.
OBDII Code P0A8C – 14-volt Power Supply Module System Voltage Unstable

P0A8D Low 14 Volt Power Supply System Module Voltage

🔧 Code P0A8D – Low Voltage in the 14-Volt Power Supply System Module

❓ What Does Code P0A8D Mean?

The P0A8D code indicates that the Engine Control Module (ECM) has detected insufficient voltage in the vehicle’s 14-volt power supply system.

This module is often used in hybrid or electrified vehicles, where it powers certain components at 14V (different from the traditional 12V system or the high-voltage system).

⚠️ Possible Symptoms

  • Check Engine or Service Engine Soon light illuminated,

  • No other noticeable symptoms in some cases,

  • In hybrid vehicles: possible partial deactivation of auxiliary electrical systems (air conditioning, power steering, etc.),

  • In severe cases: failure to charge the 12V battery.

🔍 Possible Causes

  • Faulty 14V Power Supply Module,

  • Open or shorted wiring in the 14V power circuit,

  • Loose, corroded, broken, or improperly connected connector,

  • Poor ground or poor contact in the circuit.

🛠️ How to Repair Code P0A8D?

Here are the recommended steps:

1. Visual Inspection

  • Locate the 14V power supply module (refer to the manufacturer’s manual),

  • Check the connectors: look for bent, corroded, or broken pins,

  • Inspect the wires for any damage, cuts, or melting.

2. Check Connections

  • Clean all relevant connectors,

  • Reconnect them securely after inspection.

3. Electrical Testing with a Multimeter (DVOM)

  • Measure the module’s output voltage (it should be close to 14 volts),

  • Check the circuit’s ground and continuity,

  • Ensure the input power is also correct.

4. Clear Codes and Test

  • Clear the code with an OBD-II scanner,

  • Start the vehicle and monitor if the code returns.

5. If the Code Returns…

  • Replace the 14-volt power supply module if confirmed faulty after testing,

  • Also check that the fuse associated with this module is not blown.

📌 Note

The P0A8D code is often specific to Toyota, Lexus, Honda hybrid vehicles, etc. On these models, the 14V module may be integrated into the inverter or the DC-DC converter. Therefore, it is sometimes necessary to consult a manufacturer’s repair manual to accurately identify the component.