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.
1986 Mercury Sable L4-153 2.5L HSCFACTORY OEM SERVICE PROCEDURE
System Inputs
The ECA controls various engine operating conditions by monitoring input signal. These inputs include:
1. Air conditioning signals.
2. Air charge temperature (ACT) sensor.
3. Barometric pressure (BP) sensor.
4. Brake ON/OFF (BOO) switch.
5. Clutch engaged switch.
6. EGR valve position (EVP) sensor.
7. Engine coolant temperature (ECT) sensor.
8. Exhaust gas oxygen (EGO) sensor.
9. Heated exhaust gas oxygen (HEGO) sensor.
10. Ignition diagnostic monitor (IDM).
11. Idle tracking switch (ITS).
12. Inferred mileage sensor (IMS).
13. Key power (KEYPWR).
14. Knock sensor (KS).
15. Manifold absolute pressure (MAP) sensor.
16. Neutral drive switch (NDS).
17. Neutral gear switch.
18. Neutral pressure switch (NPS).
19. Octane switch (OS).
20. Pressure feedback EGR (PFE) transducer.
21. Profile ignition pickup (PIP).
22. Power steering pressure switch (PSPS).
23. Self-test input (STI).
24. Speed control command switches (SCCS).
25. Transmission hydraulic switch (THS 4-3/3-2 shift).
26. Throttle position (TP) sensor.
27. Vane airflow (VAF) meter.
28. Vane air temperature (VAT) sensor.
29. Vehicle speed sensor (VSS).
Not all inputs are used on any one vehicle.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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