P2E8D: Battery Charger B Charge Sequence Signal 1 Circuit Low

What it means

The charge sequence signal 1 circuit of battery charger B reports voltage below the expected window. Charging handshake compromised.

At a glance

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

How it works

Battery charger B uses charge-sequence signal 1 to take part in the charging handshake. The control module sets this code when the signal falls below its expected range, which can disrupt charger B communication and charging.

Common causes

Most likely first.

1. Signal wire shorted to ground
2. Open in signal wire
3. Connector pins corroded - high contact resistance

Symptoms

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

How to diagnose it

1. Review charger-related codes and freeze-frame data, and note whether the fault coincides with a failed start, interruption, or slow charge.
2. Inspect charger B signal 1 connectors and wiring for corrosion, loose terminals, broken insulation, or a disconnected wire.
3. With the system safely isolated according to the vehicle procedure, check for a short from signal 1 to ground.
4. Measure the signal at the appropriate connector and compare the result with the manufacturer's specification to confirm the low condition.
5. If no short or connector fault is found, check signal 1 continuity end to end and test the charger input using the manufacturer's procedure.

Common fixes

• Clean corroded connector pins and restore a secure connection on signal 1.
• Repair a signal 1 wire shorted to ground.
• Repair an open or damaged signal 1 wire.
• Replace or repair charger B only if its input fails testing with the circuit wiring intact.

Can I keep driving?

A low signal can prevent charging from starting or cause interruptions and reduced charge rate. Keep sufficient battery charge for your needs and avoid relying on charger B until the circuit is repaired.