Code Definition

P1803 — Transmission Clutch Interlock Safety Switch Short Circuit To Ground

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

About P1803

P1803 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 P1803 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) 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.

P1803 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 P1803 when it detects a short circuit to ground in the clutch interlock safety switch circuit. This switch ensures the clutch is fully depressed before allowing engine startup in manual transmission vehicles. A short to ground means the circuit is continuously grounded, preventing the PCM from receiving the correct signal.

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