International SA 33 SPN 520840 FMI 13: Unexpected switch in 12-pack (MID 5) bottom row position 1 from left (Switch 7 of 12)

SA 33 SPN 520840 FMI 13 on International / Navistar trucks means: Unexpected switch in 12-pack (MID 5) bottom row position 1 from left (Switch 7 of 12). The failure mode (FMI 13) is “out of calibration”.

Code details

Manufacturer: International (Navistar)
Applies to: International / Navistar body controller (ESC) and multiplexed modules
Fault code: SA 33 SPN 520840 FMI 13
J1939 SPN: 520840
FMI: 13 — Out of calibration
Reporting module: Body Controller (source address 33)
Component / signal: Switch 12-Pack Location 7
Truck models in source: 3200, 4100, 4300, 4400, 7300, 7400, 7500, 7600, 7700, 8500, 8600, BE 200, CE Bus, CXT, DuraStar, LoneStar, MXT, ProStar, RXT, TranStar, WorkStar
Logical signal: P_J1708IN_5_254_164_2_1 _1

Cause and when it sets

Cause: Switch actuator installed or bad microswitch in location configured as empty

What to do next

Read active and inactive codes with the OEM service tool (Diamond Logic Builder can clear previously active codes) and note the occurrence count.
FMI 13 tells the shop the type of failure to test for: out of calibration.
Have a heavy-duty diesel technician confirm the fault against the engine or chassis service manual before replacing parts.