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 13 (ENGINE CONTROLS - TESTS W/CODES - EEC 1.8L)
1991 Mercury Tracer Base, 4D Sedan, Automatic
Section 13 (Engine Controls - Tests W/Codes - EEC 1.8L)
1991 Mercury Tracer Base, 4D Sedan, AutomaticSECTION Section 13 (Engine Controls - Tests W/Codes - EEC 1.8L)
WARNING: This page is about a different car, the 1994 Mercury Tracer and 1994 Ford Escort. However, it is still accessible from the selected car via links, so may be relevant.
- Introduction
- Self-Diagnostic System
- Circuit Tests
- Notes
- How To Use Circuit Tests
- Test Equipment
- Circuit Test BARO - Barometric Pressure Sensor
- Circuit Test CID - Cylinder Identification Sensor
- Circuit Test CKP - Crankshaft Position Sensor
- Circuit Test ECT - Engine Coolant Temperature Sensor
- Circuit Test IAT - Intake Air Temperature Sensor
- Circuit Test IDM - Ignition Diagnostic Monitor (IDM)
- Circuit Test Mil - Malfunction Indicator Light
- Circuit Test O2S - Oxygen Sensor
- Circuit Test PGC - Power & Ground Check
- Circuit Test Roc - Relay Output Check
- Circuit Test SCG - Solenoid Controlled By Ground
- Circuit Test SML - Switch Monitor Light
- Circuit Test STG - Switch To Ground
- Circuit Test STI - Self-Test Input
- Circuit Test STO - Self-Test Output
- Circuit Test STP - Switch To Power
- Circuit Test TP - Throttle Position Sensor (A/T)
- Circuit Test VAF - Volume Airflow Sensor
- Circuit Test VPWR - Vehicle Power
- Circuit Test VREF - Reference Voltage
- Summary
- Wiring Diagrams
RENDER: 1.0x
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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.