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.
2002 Mercury Sable LS PremiumFACTORY OEM SERVICE PROCEDURE
Test E: Electronic Automatic Temperature Control Module Does Not Respond To Scan Tool
WARNING: This page is about a different car, the 2002 Mercury Grand Marquis and 2002 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Perform all voltage and resistance tests using a Digital Volt-Ohm Meter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
- Turn ignition switch to LOCK position. Disconnect Electronic Automatic Temperature Control (EATC) module 20-pin harness connector C228a. See Fig 1. EATC harness connector is located behind center of dash panel. See Figure. Inspect harness connector for loose, damaged or corroded terminals. If connector and terminals are okay, go to next step. If connector and terminals are faulty, repair or replace as necessary. After repair, test system for normal operation.
- Connect EATC module harness connector C228a. Connect Worldwide Diagnostic System (WDS) tester or New Generation Star (NGS) tester to Data Link Connector (DLC). DLC is located under instrument panel between steering column and radio. See Figure. Turn ignition switch to RUN position. Perform data link diagnostic procedure. See DATA LINK DIAGNOSTIC TEST under SELF-DIAGNOSTIC SYSTEM. If WDS or NGS tester responds with EATC: NO RESPONSE ON CKT914 (BUS +), go to next step. If WDS or NGS tester does not respond with EATC: NO RESPONSE ON CKT914 (BUS +), go to step 4.
- Turn ignition switch to LOCK position. Disconnect WDS or NGS tester. Disconnect EATC module harness connector C228a. Measure resistance between EATC module harness connector C228a terminal No. 15 and DLC terminal No. 2 (Tan/Orange wire). See Figure and Fig 1 . See WIRING DIAGRAMS . If resistance is 5 ohms or less, replace EATC module. See ELECTRONIC AUTOMATIC TEMPERATURE CONTROL MODULE under REMOVAL & INSTALLATION. If resistance is greater than 5 ohms, repair open circuit in Tan/Orange wire between EATC module and DLC. After repair, test system for normal operation.
- Turn ignition switch to LOCK position. Disconnect WDS or NGS tester. Disconnect EATC module harness connector C228a. Measure resistance between EATC module harness connector C228a terminal No. 1 and DLC terminal No. 10 (Pink/Light Blue wire). See Figure and Fig 1 . See WIRING DIAGRAMS . If resistance is 5 ohms or less, replace EATC module. See ELECTRONIC AUTOMATIC TEMPERATURE CONTROL MODULE under REMOVAL & INSTALLATION. If resistance is greater than 5 ohms, repair open circuit in Pink/Light Blue wire between EATC module and DLC. After repair, clear DTCs and test system for normal operation.
Factory Service Tools
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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.