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Home >> Toyota >> 2000 >> RAV4 Base, AWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 21 (Engine Control System Self-Diagnostics) >> Diagnostic Tests >> DTC P1520: Stoplight Switch Signal Circuit (A/T) >> Diagnosis & Repair
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Diagnosis & Repair

WARNING: This page is about a different car, the 2000 Toyota Celica. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check stoplight operation. If stoplights do not operate properly, repair as necessary and retest system. See EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT. If stoplights operate properly, go to next step.
  2. Access ECM in driver's side of engine compartment, next to battery. Turn ignition on. Using DVOM, backprobe ECM harness connector and measure voltage between ground and terminal No. 6 (Green/White wire) at ECM harness connector E3. See Figure. With brake pedal depressed voltage should be 7.5-14.0 volts. With brake pedal released, voltage should be less than 1.5 volts. If voltage is not as specified, go to next step. If voltage is as specified, problem is intermittent. Check component and ECM connections.
  3. Check for short in wiring between ECM and stoplight switch. If problem exists, repair wiring as necessary. If problem does not exist, replace ECM.
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