P1661
Output Circuit Check Signal Low
Findings, check these first
- Output circuit shorted to ground
- Open output driver
- Blown output fuse
- Damaged harness
- PCM fault
Standard procedure
- Check related fuses
- Test for shorts to ground
- Verify output continuity
- Inspect harness routing
- Repair the circuit
Code lookup
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Sources and review
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- OBDII.pro: P1661 Ford definition
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Supports: Ford-family meaning for P1661: Output Circuit Check Signal Low
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Last updated 2026-09-06.
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