P0652 — Sensor reference voltage B — electrical input low

The monitor for sensor reference voltage b detects an electrical value below the allowed range; this does not by itself mean that speed, pressure or temperature is physically low. A, B and C label different reference circuits, not fixed lists of sensors across makes. The definition does not mean a traction high-voltage fault.

Affected system: Sensor reference-voltage circuits

Symptoms

• The engine warning light may be accompanied by hesitation or reduced power.
• Other faults may appear if several sensors depend on the same low reference voltage.

Possible causes

• A defective sensor connected to reference circuit B can reduce the shared voltage.
• Damaged or corroded wiring and connectors may cause a low electrical input.

What to check

• Read associated codes and identify the reference B consumers for the vehicle.
• Inspect the shared wiring and connectors, then measure circuit voltage against the service specification.
• Use the approved troubleshooting sequence to identify the affected sensor or branch before replacement.

Also written as: P0652-00, P065200, PO652 (some scan tools add the fault-type byte, e.g. -00).