Some 2021-2023 F-150 and 2022-2023 F-Super Duty/Expedition/Navigator/Maverick vehicles equipped with an integrated trailer module (iTRM) may exhibit a trailer lamp fault message with various related diagnostic trouble codes (DTC). Most trailer emulator testers will not draw enough current to correctly diagnose these concerns. They may be used to diagnose basic functionality of the iTRM, however, some trailer emulator testers may cause false trailer lamp fault messages to appear. The customer's trailer should be used for diagnosis instead of a trailer emulator tester. Refer to Workshop Manual (WSM), Section 417-01 for normal diagnostics.
