LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2002 >> RAV4 Base, AWD, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics >> Diagnostic Tests >> DTC P1520: Stoplight Switch Signal Circuit >> Diagnosis & Repair
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis & Repair

  1. If Toyota hand-held tester is available, go to next step. If Toyota hand-held tester is not available, go to step  6.
  2. Check stoplight operation. If stoplights operate properly, go to next step. If stoplights do not operate properly, repair as necessary and retest system. See EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT.
  3. Connect hand-held tester to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. See Figure. Turn ignition on and then turn hand-held tester on.
  4. Monitor STP signal on hand-held tester while depressing and releasing brake pedal. STP signal should indicate ON with brake pedal depressed and OFF with brake pedal released. If STP signal is not as specified, go to next step. If STP signal is as specified, problem is intermittent. Check for defective connections or intermittent problem in wiring between stoplight switch and ECM. See WIRING DIAGRAMS article. Stoplight switch is located near top of brake pedal. ECM is located behind passenger's side kick panel, just below instrument panel. See Figure.
  5. Check wiring harness and electrical connectors between stoplight switch and ECM. See WIRING DIAGRAMS article. Stoplight switch is located near top of brake pedal. ECM is located behind passenger's side kick panel, just below instrument panel. See Figure. If wiring harness and electrical connectors are okay, replace ECM. If wiring harness or electrical connectors are defective, repair as necessary.
  6. Check stoplight operation. If stoplights operate properly, go to next step. If stoplights do not operate properly, repair as necessary and retest system. See EXTERIOR LIGHTS article in ACCESSORIES & EQUIPMENT.
  7. Remove glove box and passenger's side kick panel (if necessary) for access to ECM with electrical connectors still installed on ECM. See Figure.
  8. Turn ignition on. Using voltmeter, check voltage between body ground and terminal No. 15 (Green/White or White wire) at ECM electrical connector E8 while depressing and releasing brake pedal. See Figure. This is the STP terminal on ECM. There are 2 different wiring harnesses used and wire color varies according to wiring harness used.
  9. 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 within specification, go to next step. If voltage is within specification, problem is intermittent. Check for defective connections or intermittent problem in wiring harness and electrical connectors between stoplight switch and ECM and for intermittent problem with stoplight switch. See WIRING DIAGRAMS article. Stoplight switch is located near top of brake pedal.
  10. Check wiring harness and electrical connectors between stoplight switch and ECM. See WIRING DIAGRAMS article. Stoplight switch is located near top of brake pedal. If wiring harness and electrical connectors are okay, replace ECM. If wiring harness or electrical connectors are defective, repair as necessary.
scientia non olet · About LEMON Manuals