diff --git a/arch/arm/src/stm32l4/stm32l4_hsi48.c b/arch/arm/src/stm32l4/stm32l4_hsi48.c
index 28fa3aa7c03..11234c1fd47 100644
--- a/arch/arm/src/stm32l4/stm32l4_hsi48.c
+++ b/arch/arm/src/stm32l4/stm32l4_hsi48.c
@@ -136,11 +136,12 @@ void stm32l4_enable_hsi48(enum syncsrc_e syncsrc)
 
   /* Set the AUTOTRIMEN bit the CRS_CR register to enables the automatic
    * hardware adjustment of TRIM bits according to the measured frequency
-   * error between the selected SYNC event.
+   * error between the selected SYNC event. Also enable CEN bit to enable
+   * frequency error counter and SYNC events.
    */
 
   regval  = getreg32(STM32L4_CRS_CR);
-  regval |= CRS_CR_AUTOTRIMEN;
+  regval |= CRS_CR_AUTOTRIMEN | CRS_CR_CEN;
   putreg32(regval, STM32L4_CRS_CR);
 }