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.
Circuit Description
Transaxle Pressure Switch Assembly (PSA) consists of 6 pressure switches. One switch is normally-closed and is used to detect TCC release fluid pressure. Other switches are normally-open and are used for determining gear range selection. PSA contains Transaxle Fluid Temperature (TFT) sensor. These components are combined into one unit and mounted on control valve body.
TCM provides battery voltage on each range signal. By grounding one or more switches with fluid pressure from manual shift valve, TCM detects selected gear range. When transaxle electrical connector is disconnected and ignition is on, ground potential for 3 range signals from TCM will be removed, and an illegal gear will be indicated. See PSA LOGIC table. DTC P1810 will set when TCM detects an invalid gear status, a drive range after start-up or an incorrect gear ratio.
| Gear | Signal "A" | Signal "B" | Signal "C" |
|---|---|---|---|
| Park | On | Off | Off |
| Reverse | On | Off | On |
| Neutral | On | Off | Off |
| Drive/OD | On | On | Off |
| D3/3rd | Off | On | Off |
| D2/2nd | Off | On | On |
| D1/Lo | On | On | On |
| Illegal | Off | Off | Off |
| Illegal | Off | Off | On |
NO RELATED
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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.