Hi Maidin! ERP was not charged possible due to a defective IU, an expired or improperly inserted stored-value card, or because there was insufficient value in your card, you will receive a notification within a few days after the violation. Check this LTA link for more details: https://onemotoring.lta.gov.sg/content/onemotoring/home/driving/ERP/ERP.html

To avoid violations due to your stored-value card being expired, improperly inserted or having insufficient value, consider using a backend payment service, check here: https://onemotoring.lta.gov.sg/content/onemotoring/home/driving/ERP/ERP.html#backend-payment-services