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.
1990 BMW 325is AutomaticFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Self-Diagnostic System
- Entering Self-Diagnostics
- Retrieving Codes (Approved Method)
- Retrieving Codes (Alternate Method)
- Trouble Code Diagnosis
- Testing
- * Please Read First Before Testing *
- Main Relay Control
- Voltage Supply To Control Unit
- Main Grounds
- Throttle Switches
- Fuel Pump Relay Control
- Fuel Injector Control (Injectors 1, 3 And 5)
- Fuel Injector Control (Injectors 2, 4 And 6)
- Starter Input (Terminal 50)
- Reference Sensor
- Coolant Temperature Sensor
- Idle Air Stabilizer Valve
- Air Flow Sensor
- Evaporative Emissions Purge Valve
- Cylinder Identification Sensor
- Air Conditioning On Signal
- Automatic Transmission Park/Neutral Signal
- Summary
Factory Service Tools
Use the Manual With the Right Hardware
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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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