Ignition switch "OFF"
Connect VMI to GDS and set up the Oscilloscope.(2 Channel):
Channel A (+) : Pin No. 1 (Signal) terminal (Brake booster vacuum pressure sensor harness connector)
Channel A (-) : Ground
Ignition switch "ON" & Engine "ON"
Inspection condition : Ignition switch "ON" & Engine "ON" & Brake pedal operation.
Specification : Signal voltage decreases when brake pedal is pressed
Fig.1) Section A : Brake booster vacuum pressure sensor signal voltage is decreased when brake pedal is pressed.
Section B : When brake pedal is not pressed, vacuum is built up in the brake booster and sensor signal voltage increases as vacuum is built up.
Is the measured value within specification?
 | ▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure. |
 | ▶ Carefully re-do this troubleshooting guide steps. ▶ If no problems were found with the circuits or connectors, replace the Brake booster vacuum pressure sensor and go to "Verification of Vehicle Repair" procedure. |
When installing component, tighten it within specification
If component is dropped, check for proper operation. The internal damage may be present
