P1660 Output Circuit Check Signal High

Category: Powertrain - Computer and Auxiliary Controls
Severity: Check Engine Light
Applies to: F-150, Mustang, Explorer, Ranger

What does P1660 mean on a Ford?

P1660 — Output Circuit Check Signal High. This Ford-enhanced code applies to F-150, Mustang, Explorer, Ranger.

Common causes of P1660

Output circuit shorted to voltage
Failed output driver stuck high
Backfed voltage from a shared circuit
Corroded connector bridging power
PCM fault

How to fix P1660

Identify which output the monitor watches
Check for shorts to power
Isolate shared circuits
Test the output driver
Repair wiring per findings