diff --git a/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay b/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay
index 344ac9b01ff..24a6de6f370 100644
--- a/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay
+++ b/tests/drivers/lpuart/boards/nrf9160dk_nrf52840.overlay
@@ -18,8 +18,13 @@
 
 	uart1_sleep_alt: uart1_sleep_alt {
 		group1 {
-			psels = <NRF_PSEL(UART_TX, 0, 17)>,
-				<NRF_PSEL(UART_RX, 0, 20)>;
+			psels = <NRF_PSEL(UART_TX, 0, 17)>;
+			low-power-enable;
+			bias-pull-up;
+		};
+
+		group2 {
+			psels = <NRF_PSEL(UART_RX, 0, 20)>;
 			low-power-enable;
 		};
 	};
diff --git a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay
index fcee1764b7d..01f2a2e0ac2 100644
--- a/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay
+++ b/tests/drivers/lpuart/boards/nrf9160dk_nrf9160.overlay
@@ -34,8 +34,13 @@
 
 	uart2_sleep_alt: uart2_sleep_alt {
 		group1 {
-			psels = <NRF_PSEL(UART_RX, 0, 17)>,
-				<NRF_PSEL(UART_TX, 0, 18)>;
+			psels = <NRF_PSEL(UART_TX, 0, 18)>;
+			low-power-enable;
+			bias-pull-up;
+		};
+
+		group2 {
+			psels = <NRF_PSEL(UART_RX, 0, 17)>;
 			low-power-enable;
 		};
 	};
diff --git a/tests/drivers/lpuart/prj.conf b/tests/drivers/lpuart/prj.conf
index 0f701642aab..2584cd606b2 100644
--- a/tests/drivers/lpuart/prj.conf
+++ b/tests/drivers/lpuart/prj.conf
@@ -13,5 +13,6 @@ CONFIG_TEST_LOGGING_DEFAULTS=n
 CONFIG_COUNTER=y
 
 CONFIG_TEST_LPUART_TIMEOUT=10
+CONFIG_PINCTRL_KEEP_SLEEP_STATE=y
 
 CONFIG_ASSERT=y
diff --git a/tests/drivers/lpuart/src/main.c b/tests/drivers/lpuart/src/main.c
index 8c6086b68c4..108aa012cb5 100644
--- a/tests/drivers/lpuart/src/main.c
+++ b/tests/drivers/lpuart/src/main.c
@@ -238,6 +238,8 @@ ZTEST(test_lpuart_stress, test_stress)
 	k_timer_stop(&kill_timer);
 	zassert_equal(err, 0, NULL);
 	zassert_false(test_err, NULL);
+	/* Detect premature kill packet. */
+	zassert_true(rx_cnt > 100);
 	zassert_equal(tx_req_cnt, tx_done_cnt, NULL);
 
 	k_msleep(100);