Detroit DD13 EPA10 (2010-13) Fault Code: SPN 520232 FMI 9 (MCM, CPC, ACM) NOx Mass Signal Not Available via Controller Area Network

Posted by PerDiezel Solutions on March 11, 2026

NOTE: Please see the step by step troubleshooting procedures for this specific code.

PROBABLE CAUSES:
1. If any engine ECM has been recently programmed, ensure the parameters are correct.
2. Turn key off, wait 5 minutes, turn back on. If code doesn’t go active, clear code and release truck to customer.
3. Follow 625-9 for troubleshooting.

WARNING!