DTC codes / Ford codes / P1357
P1357 on Ford vehicles means the powertrain control module (PCM) is receiving an ignition diagnostic monitor (IDM) signal whose pulsewidth falls outside the range the PCM can interpret, so it cannot determine a valid dwell or spark event timing. The PCM monitors the IDM feedback circuit from the ignition control module or coil drivers and flags this code when the pulsewidth is missing, erratic, or electrically undefined rather than a clean square wave.
Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.
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