P0621

Symptoms

• The battery light comes on or flashes
• The Check Engine light comes on
• Unstable charging voltage
• Sometimes - normal charging operation if there is a code
• Possible incorrect behavior of the charging control system

Causes

• Burnt out or broken control lamp in terminal L circuit
• Broken wire terminal L between the generator and the instrument panel/ECU
• Short circuit of terminal L wire to ground
• Malfunction of the voltage regulator with terminal L
• Oxidation of the generator connector

How to Fix

1. Check the status of the battery warning lamp on the dashboard
2. Measure the voltage at terminal L of the generator with the engine running.
3. Check wiring from terminal L to instrument panel and ECU
4. Check the generator connector - clean it from oxidation
5. Check generator voltage regulator
6. If the external circuit is working, diagnostics/replacement of the generator

Related codes

Error P0621 by Vehicle Brand