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Home >> Infiniti >> 2003 >> Q45 >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 201 (Engine Control System) >> DTC P1805: Brake Switch >> Diagnostic Procedure >> 4. Check Stop Lamp Switch Input Signal Circuit For Open And Short
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4. Check Stop Lamp Switch Input Signal Circuit For Open And Short

WARNING: This page is about a different car, the 2004 Infiniti Q45. However, it is still accessible from the selected car via links, so may be relevant.
  1. Disconnect ECM harness connector.
  2. Disconnect stop lamp switch harness connector.
  3. Check harness continuity between ECM terminal 106 and stop lamp switch terminal 2.

    Refer to Wiring Diagram.

    1. Continuity should exist. 
  4. Also check harness for short to ground and short to power.

OK or NG 

OK: GO TO 6.

NG: GO TO 5.