Cummins ISB CM550 (1990-94) Fault Code: 243 PID: 121 SPN: 513 FMI: 4 Exhaust Brake Supply Circuit

Circuit Description
The electronic control module (ECM) enables the exhaust brake by sending a signal to the
relay that controls the exhaust brake under certain conditions.

Component Location
Refer to the original equipment manufacturer’s (OEM) diagram for the location of the engine brake.

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