SA 16 DTC Explained = OBD / P-Codes
Heavy-duty truck fault codes do share similar results with the OBD automotive standard, but the heavy-duty manufacturers do things a little differently. This is why we recommend using good sources for your information so you have the right information to fix your truck.
Which trucks use OBD Fault codes?
- Volvo Trucks 2014+
- Mack trucks 2014+
- Prevost Bus 2014+
Here is look at some fault code data that you may have seen on your dashboard. The following information is on a 2015 Volvo VNL 670 with a Volvo 500hp D13 engine with I-shift.
Fault #1: SA 16 DTC P113000
[SA] stands for Source Address. In this particular example, the “16” stands for the engine. So this fault code is coming from the Engine ECU. This can also be labeled as "SA 0" as well.
[DTC] stands for Diagnostic Trouble Code
[P] stands for Powertrain
[1130] stands for Aftertreatment Hydrocarbon Air Purge Valve
[00] stands for (stuck closed), this is the failure mode that sets this fault
Fault #2: SA 16 DTC P20EE00
[SA] stands for Source Address. In this particular example, the “16” stands for the engine. So this fault code is coming from the Engine ECU. This can also be labeled as "SA 0" as well.
[DTC] stands for Diagnostic Trouble Code
[P] stands for Powertrain
[20EE] stands for NOx Catalyst - Conversion Efficiency Low
[00] stands for (Below The Threshold), this is the failure mode that sets this fault
This OBD monitor is designed to determine the DEF efficiency as calculated by using the inputs of the commanded DEF and the two NOx sensors located upstream and downstream of the NOx Catalyst.
Take a look at the Inlet / Outlet NOx Sensor location and make sure they are not damaged. Good NOx sensors can eliminate a lot of false positives on the SCR system.
- Inlet NOx Sensor Location: Before your DOC/DPF system
- Outlet NOx Sensor Location: After your SCR system
A defective SCR operation can cause the dreaded "service def vehicle speed limited to 5 mph." If this happens you need to clear the SCR derate with a dealer level tool, or with OTR Diagnostics. The reset will remove the derate message off the instrument cluster and will allow you to drive past 5 mph. You can have NO ACTIVE CODES and still be derated to 5 MPH - keep this in mind if you run into this scenario. There is a special reset that gets rid of this message on your dash once you have fixed the DEF / SCR system.
So now you may be asking yourself, what is a good resource for checking fault codes?
We recommend truckfaults.com. This free software can be used by anyone who has internet service. Once you are on the TruckFaults application you just enter your fault codes in the search bar and then learn in detail about the fault codes you have.
Until next time! 👋
Stay safe, stay healthy & be blessed.
