ecm-900a
Moderate
Volvo · SUVs
Engine Control Module - High Voltage Supply Error
Quick Answer
Error code ECM-900A on your Volvo SUVs means: Engine Control Module - High Voltage Supply Error. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Check battery voltage with multimeter
2
Test alternator output voltage
3
Inspect battery terminals for corrosion
4
Check main power relay operation
5
Verify ECM ground connections
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
battery
alternator
voltage regulator
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