P2E90: Battery Charger A Internal Power Supply Performance

What it means

The internal low-voltage power supply of battery charger A does not maintain the expected output. Internal regulator drift or overload.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Battery charger A has an internal low-voltage supply that supports its control electronics. The vehicle monitors charger A's supply performance and sets this code when the supply does not stay within its expected operating range, potentially affecting charging.

Common causes

Most likely first.

1. Internal regulator drifted
2. Internal load increased

Symptoms

• Charge status indicator shows fault
• Charging may not start or interrupts
• Slower-than-expected charge rate

How to diagnose it

1. Read all charging-system codes and freeze-frame data, and note whether the fault appears during a charge attempt or under load.
2. Check the vehicle's charging status and available scan-tool data for evidence that charger A's internal supply fault is repeatable.
3. Inspect charger A's accessible connectors and wiring for poor contact, corrosion, damage, or signs of overheating.
4. Verify the external low-voltage supply and grounds serving charger A against the manufacturer's specification to rule out vehicle-side power problems.
5. If external power, grounds, and connections are sound, test charger A's internal supply performance using the manufacturer's diagnostic procedure.

Common fixes

• Clean and secure charger A's accessible power, ground, and control connectors.
• Repair damaged external power or ground wiring to charger A.
• Repair or replace charger A if its internal supply fails testing after external circuits are verified.

Can I keep driving?

Charging may be unavailable, interrupted, or slower than expected, and the vehicle may limit charging functions. Plan around the available battery charge and avoid depending on charger A until its supply fault is addressed.