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.
1987 Mazda 626 BaseFACTORY OEM SERVICE PROCEDURE
626 Turbo
CONTROL UNIT TESTING (626 TURBO)(1)
| Terminal | Connection | Voltage (When Operating Properly) | ||
|---|---|---|---|---|
| 1A & 1D | Digital Code Tester | Below 1.5V or About 12V Depending on Signal | ||
| 1C | Air By-Pass Solenoid Valve "B" | About 12V | ||
| 1E | Idle Switch (In Throttle Position Sensor) | Below 1.5V at Idle | ||
| 1G | Neutral & Clutch Switch | About 12V (In Neutral), Below 1.5V (In Gear) | ||
| 1H | Coolant Temperature Switch | Below 1.5V | ||
| 1I | Pressure Switch | About 12V | ||
| 1J | Brake Switch | About 12V When Depressing Brake Pedal | ||
| 1L | A/C Clutch Circuit | Below 1.5V When Switch Is "Off" | ||
| 1M | Ignition Coil Negative Terminal | About 12V | ||
| 1S | Turbocharger Indicator Light | About 12V (Below 1.5V @ 2000 RPM or Greater) | ||
| 1U | Knock Control Unit | Below 1.5V | ||
| 1V | Air By-Pass Solenoid Valve "C" | About 12V | ||
| 2A | Atmospheric Pressure Sensor, EGR Position Sensor, Throttle Position Sensor | Between 4.5-5.5V | ||
| 2B | Airflow Meter "Vc" Terminal | Between 6-10V | ||
| 2C | Atmospheric Pressure Sensor, Airflow Meter, Coolant Thermosensor, Throttle Position Sensor, EGR Position Sensor | Below 1.5V | ||
| 2D | Oxygen Sensor | Zero | ||
| 2E | Airflow Meter "Vs" Terminal | Between .7-2.7V | ||
| 2F | EGR Position Sensor | 0-1.5V | ||
| 2G | Throttle Position Sensor | Between .4-.6V | ||
| 2H | Atmospheric Pressure Sensor | About 4V (At Sea Level) | ||
| 2I | Coolant Thermosensor | About .5V | ||
| 2J | Intake Air Temperature Sensor | About 2.3V at 68°F (20°C) | ||
| 2K | Pressure Regulator Control Valve | About 12V (Below 1.5V 2 Minutes After Starting) | ||
| 2M & 2N | Duty Solenoid Valves | About 12V (2M For Vent, 2N For Vacuum) | ||
| 2P | Three-Way Solenoid Valve (Purge Control) | About 12V | ||
| 2R | Engine Ground | Below 1.5V | ||
| 3A & 3G | Engine Ground | Below 1.5V | ||
| 3B | Ignition Switch "START" Position | Below 1.5V | ||
| 3C & 3E | Injectors | About 12V (3C Injectors 2 & 4, 3E Injectors 1 & 3) | ||
| 3J | Main Relay | About 12V | ||
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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.
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