NOX Sensor TesterFault CodesNOX Sensor Fault CodesCommon fault codes related to NOX sensors and SCR aftertreatment systems.Coming soon.Software UpdatesKeep your NOX Sensor Tester firmware and app up to date for the latest vehicle coverage.NOX Sensor Fault Codes ExplainedDiagnose upstream and downstream NOX sensor faults including SPN 3216, 3226, 3242, and 3246.