P05A8

Symptoms

• Check Engine light is on
• Blinds do not work, disabled by security system
• There may be signs of on-board network overcharging (bright headlights, rapid battery discharge)
• Other electrical systems may behave abnormally
• Errors in the BCM or other control modules

Causes

• Alternator voltage regulator malfunction (overcharging)
• Voltage surge in the on-board network when the loads are disconnected
• Incorrect installation of additional equipment with electrical violations
• Malfunction of the protective stabilizer in the power supply circuit of the blinds
• Short to higher voltage circuit (rare)

How to Fix

1. Measure the voltage of the on-board network with the engine running - it should be 13.5–14.5 V
2. If the voltage is above 15 V, check and replace the generator voltage regulator
3. Check the condition of the battery - a faulty battery can cause voltage surges
4. Measure the voltage directly in the power supply circuit of the blinds and compare with the voltage of the on-board network
5. Inspect additional equipment installed in the vehicle's electrical network
6. After normalizing the on-board network voltage, reset the codes and check the operation of the blinds
7. If the code appears again, check the protective elements in the blinds power circuit

Related codes

Error P05A8 by Vehicle Brand