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DTC codes / P0Axx · Hybrid propulsion / P0A98

P0A98Hybrid/EV Battery Pack Cooling Fan 2 Stuck On

P0A98 indicates that the hybrid or electric vehicle battery pack cooling fan 2 is stuck on, meaning the control module commanded the fan to stop but the fan continued running or the circuit remained energized. The computer detects this by monitoring the fan control circuit and seeing an unexpected continuous current draw or lack of response to the off command.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Cooling fan continues running long after the vehicle is shut off, draining the 12-volt battery
  • Fan runs constantly at full speed, creating noticeable noise even when the battery is cool
  • Hybrid/EV system warning light illuminated on the dashboard
  • Reduced electric range or poor hybrid battery performance due to overcooling
  • Often no symptoms besides the warning light if the fan is only intermittently stuck

Common causes, most likely first

  1. Faulty cooling fan relay that has welded its contacts closed, keeping the fan powered continuously
  2. Short circuit in the fan control wiring harness, causing a constant ground or power feed to the fan motor
  3. Failed cooling fan control module that cannot interrupt power to the fan
  4. Sticking or failed fan motor internal relay or solid-state switch
  5. Corroded or damaged connector pins at the fan motor or control module causing a short
  6. Software glitch in the hybrid/EV control module requiring a reprogramming update

How to diagnose and fix it

  1. Verify the fan actually runs with the vehicle off and key removed, then disconnect the fan connector to see if it stops
  2. Check for stored codes in all modules and review freeze-frame data to confirm the fault conditions
  3. Inspect the cooling fan relay and swap it with an identical known-good relay to see if the problem moves
  4. Perform a voltage drop test on the fan power and ground circuits while the fan is stuck on to locate a short
  5. Disconnect the fan control module and check for continuity to ground on the control circuit that should be open
  6. If the relay and wiring are good, test the fan motor directly with a fused jumper to confirm it runs only when powered
  7. Replace the faulty fan motor, relay, or control module as indicated by the tests, then clear codes and verify the fan shuts off

Don't overlook the simple relay

  • A welded cooling fan relay is the most common cause of this code, yet many technicians replace the entire fan assembly first.
  • The fan may only stick on intermittently, so a visual inspection with the key off after a long drive is more reliable than a quick glance.
  • A shorted fan control wire can be caused by chafing against the battery pack frame, which is often hidden from view.
  • This code does not always mean the fan motor is bad; the control module or a simple relay can be the culprit.
  • On some vehicles, a low 12-volt battery can cause the control module to behave erratically and set this code falsely.

Can I keep driving with P0A98?

You can usually drive the vehicle short distances to a repair shop, but avoid leaving it parked for long periods because the stuck fan can drain the 12-volt battery and leave you stranded. Do not ignore the warning light, as continued operation may over-discharge the battery or cause the hybrid system to disable.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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