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Charging and system voltage

Battery voltage, alternator and supply rails. Low system voltage cascades: P0562 arrives with a fistful of U-codes because starved modules stop answering.

6 documented codes across 28 real diagnostics.

Ranked by how often we actually see them

Code What it is Diagnostics
P0562 System voltage low 17
P0560 System voltage 6
P0621 Generator lamp or L terminal control circuit 2
P0620 Not individually documented 2
P0627 Fuel pump A control circuit open 1
P2500 Generator lamp or L terminal circuit low —

FAQ

Frequently asked questions

How do I run a diagnosis?

Select the vehicle on Start, click the Diagnostic card and choose New diagnostic. Fill in the description, the error codes and the mileage, then click Analyze.

Learn more: Diagnostic (vehicle-first start), Diagnostic form: description, error codes and mileage

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Do I have to type the codes from my scan tool?

No. Click the camera button next to Error codes and take or choose a photo (JPEG or PNG) of the scan tool's screen; WrenchLane reads the codes and their descriptions into the form. You can also speak them with the microphone.

Learn more: OBD reader photo scan (fault codes from a photo), Voice input for the problem description

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Are the public fault code pages built from my diagnostics?

They are built from anonymised, aggregated diagnostics run in WrenchLane; no workshop, customer or vehicle can be identified. Each fault code page shows how often the code was seen across those diagnostics and in how many separate workshops.

Learn more: Fault code pages on wrenchlane.com (fault-code cluster)

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More questions in the help centre

Work a charging and system voltage fault on a real car

Enter the codes and the symptoms and get ranked probable causes for that specific vehicle, with the checks in the order worth doing them. Free account, no card.

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