diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
index cb6637e82f32..416b2dd64eae 100644
--- a/drivers/usb/typec/tcpm/fusb302.c
+++ b/drivers/usb/typec/tcpm/fusb302.c
@@ -607,6 +607,8 @@ static int fusb302_set_toggling(struct fusb302_chip *chip,
 			return ret;
 		chip->intr_togdone = false;
 	} else {
+		/* Datasheet says vconn MUST be off when toggling */
+		WARN(chip->vconn_on, "Vconn is on during toggle start");
 		/* unmask TOGDONE interrupt */
 		ret = fusb302_i2c_clear_bits(chip, FUSB_REG_MASKA,
 					     FUSB_REG_MASKA_TOGDONE);