P0E74

Hybrid/EV Battery Voltage Internal Isolation Fault

Severity

🚨 Critical

Can you drive?

Do not drive — repair immediately

Approx. repair cost

$167–2778 (est.)

Symptoms

Check Engine light comes on
Reduced vehicle power
The car goes into emergency mode
High voltage system fault warning
Hybrid system start failure

Causes

Damage to battery cell insulation
Moisture gets into the battery compartment
Mechanical damage to the battery
Battery manufacturing defect
Corrosion of high voltage system contacts

How to Fix

High voltage battery diagnostics
Insulation resistance test
Replacing damaged battery cells
Repair or replacement of high-voltage battery
Checking the battery compartment for leaks

Related codes

P0E75 P0E76 P0AFA