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.
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HOMESERVICE MANUALSMERCURY1991TRACER BASE, 4D SEDAN, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 4 (ENGINE CONTROLS - TESTS W/CODES - EEC-IV)CIRCUIT TESTSCIRCUIT TEST DS - PROGRAMMABLE SPEEDO/ODOMETER MODULE (PSOM)DIAGNOSTIC AIDS
1991 Mercury Tracer Base, 4D Sedan, Automatic
Diagnostic Aids
1991 Mercury Tracer Base, 4D Sedan, AutomaticSECTION Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 1992 Mercury Tracer, 1992 Mercury Topaz, 1992 Mercury Sable, 1992 Mercury Grand Marquis, and 1992 Mercury Cougar. However, it is still accessible from the selected car via links, so may be relevant.
Perform this test when directed by QUICK TEST . This CIRCUIT TEST is intended to diagnose:
- PSOM output to ECA.
- PSOM (+) and PSOM (-) wiring harness circuits.
- ECA.
To prevent replacement of good components, be aware following non-EEC related areas and components may be cause of problem:
- Cruise control system.
- Rear anti-lock brake system.
- Instrumentation system.
RENDER: 1.0x
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.