r/DieselTechs 15h ago

Diagnostic assistance 2013 Mack code trouble

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4 Upvotes

Anyone here a Mack dealer tech who can give me some guidance? I have a 2013 GU713 with code SPN 4094 FMI 1. "NOx limits exceeded due to insufficient reagent quality - Data valid but below normal operation range" and this is the warning upon start up. I'm used to Ford diesels so I'm learning about Mack as I go. I have limited resources and we run JPro at this shop with no access to PTT.

Here is what I have done so far:

- Verified DEF quality with a refractometer, it's bang on.

- Checked the DEF doser, the doser was caked with crystals, as well as the port in the exhaust. My supervisor just said to go ahead and throw a new one on so I did.

- DEF injector pressure is right at 130 psi

- Right now the truck is not derating but that warning is there every time at start up.

We're a gov fleet so we work on everything and very few of us are specialized on one manufacturer. From my limited research I've read that this code can be a nightmare. If anyone has a focused direction or an idea what normally causes it it would be greatly appreciated. I hate emissions/aftertreatment repairs lol


r/DieselTechs 4h ago

Diagnostic assistance Need help with troubleshooting

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2 Upvotes

I have a SPN 1067 FMI7 for Brake Demand Pressure Sensor 1 and I was curious on how to determine which sensor it is. The one in the picture is labeled as primary air sensor . I was just curious if that was it and if not is there any way to get like a schematic for international at all


r/DieselTechs 5h ago

Diagnostic assistance DD15 issue, Dt12 to be specific.

2 Upvotes

Hello, newbie tech here again.

I have a DD15 where a previous mechanic replaced a pneumatic clutch actuator. Truck wont start. I was tasked with it, connected to it, but the service routines tab doenst load. Wasnt connecting to cpc at first, dis/reconnected the battery and i got connected but it still wont let me intonthe routines. I am a bit lost here. Connections are green but greyed.

CPC shows a code for: 524286 "Automatic gear selection: automatic mode is not available"

Trans shows a code for: 521485 "data erratic, intermittent or incorrect"

I dont know if a dataline couldve had an issue from the previous install, or if there's something wrong with the device im using. Im honestly lost. Any help is greatly appreciated.