Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1993 Toyota Tercel BaseFACTORY OEM SERVICE PROCEDURE
Vacuum Sensor
- Ensure ignition is off. To check vacuum sensor supply voltage, disconnect electrical connector from vacuum sensor. See VACUUM SENSOR LOCATIONS table.NOTE: Vacuum sensor may also be identified using appropriate illustration in THEORY/OPERATION article. Vacuum sensor has a vacuum hose connected to it and may be identified by wire colors. See appropriate wiring diagram in WIRING DIAGRAMS article.VACUUM SENSOR LOCATIONS
Application Location Tercel Center Of Firewall In Engine Compartment - Turn ignition on. Using voltmeter, measure voltage between terminals VCC and E2 of electrical connector on wiring harness. See Fig 1. The VCC and E2 terminals are the 2 outer terminals on all models. Voltage should be within specification. See VACUUM SENSOR SUPPLY VOLTAGE SPECIFICATIONS table.VACUUM SENSOR SUPPLY VOLTAGE SPECIFICATIONS
Application Voltage Tercel 4.00-6.00 - If supply voltage is not within specification, check wiring circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. If supply voltage is correct, turn ignition off. Reinstall electrical connector on vacuum sensor.
- To check vacuum sensor output voltage, turn ignition on. Disconnect vacuum sensor vacuum hose from intake manifold. Connect voltmeter to terminals PIM and E2 of Engine Control Module (ECM). See Fig 2. See ECM LOCATION table.ECM LOCATION
Application Location Tercel Bottom Center Of Dash, In Front Of Console - Measure and record output voltage under ambient atmospheric pressure. Attach vacuum pump to vacuum sensor.
- Apply vacuum in specified increments and measure output voltage drop at each increment. See VACUUM SENSOR OUTPUT VOLTAGE DROP SPECIFICATIONS table. Replace vacuum sensor if output voltage drop is not within specification.
VACUUM SENSOR OUTPUT VOLTAGE DROP SPECIFICATIONS
| Applied Vacuum: In. Hg | Output Voltage Drop |
|---|---|
| 3.94 | .3-.5 |
| 7.87 | .7-.9 |
| 11.81 | 1.1-1.3 |
| 15.75 | 1.5-1.7 |
| 19.69 | 1.9-2.1 |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.