Code Definition

P1801 — Transmission Clutch Interlock Safety Switch Open Circuit

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Generic

About P1801

P1801 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1801 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1801 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The powertrain control module (PCM) sets P1801 when it detects an open circuit in the clutch interlock safety switch circuit. This switch ensures the clutch is fully depressed before allowing engine startup in manual transmission vehicles. If the PCM does not receive the expected voltage signal when the clutch is engaged, it registers this fault.

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