Volvo D13 derate with SPN 1046 FMI 2 - EGR Mixer Temp Sensor

Question

My 2017 VNL is throwing a code for the EGR mixer temperature sensor and the truck is stuck in a 5 mph derate. I’m seeing erratic temperature readings on my laptop ranging from 40 degrees to 400 degrees while iding. The dash keeps saying high soot load but I just had the DPF cleaned last month.

wrenchqueen · Accepted Answer

The issue was a combination of a failed sensor and a frayed pigtail connector. I replaced the EGR Mixer Temperature Sensor (Part #21534115, roughly $115) and spliced in a new Bosch-style two-pin pigtail kit. After clearing the codes and performing a 'learned data' reset for the aftertreatment system using Tech Tool, the derate cleared and the truck has been running 1,200 miles since without an issue.

Jordan Lee · Answer

You need to verify the actual Ohm reading on that sensor. If the resistance doesn't match the temperature chart in Premium Tech Tool, the sensor internal thermistor has failed. Cleaning them rarely works because they fail internally.

Kevin Tran · Answer

Check the wiring harness where it clips to the valve cover. Those D13 harnesses are notorious for rubbing through on the metal brackets, which causes the intermittent FMI 2 signal erratic code.

shoptech_carlos · Answer

Make sure your EGR valve isn't stuck partially open. If the valve is leaking exhaust gas when it should be closed, it can heat that mixer sensor up outside of the expected parameters and trigger the 1046 code.

Volvo D13 derate with SPN 1046 FMI 2 - EGR Mixer Temp Sensor

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