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.
Automatic Trans: Diagnosis: Description: Notes
Saturn vehicles use a 4-speed, fully automatic, electronically controlled transaxle with shift mode select function and self-diagnostic function.
The transaxle uses 5 electronic valves (line actuators), controlled by the Powertrain Control Module (PCM). The PCM controls all transaxle shifts, shift feel, Torque Converter Clutch (TCC) lock-up and self-diagnostics. PCM is located behind right side of dash. PCM has two 32-pin and one 24-pin connector.
If an electrical circuit problem occurs, SERVICE ENGINE SOON or SHIFT TO D2 light may come on or start flashing. PCM will store trouble codes or information flags in memory. A stored trouble code indicates PCM has detected a fault in engine or transaxle circuits. Information flags help diagnose current or intermittent trouble codes.
PCM is capable of operating in 2 different modes. The differences between the 2 modes are shift points. NORMAL mode or PERFORMANCE mode may be selected using mode switch. Mode switch is located on center console.
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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.