2002 Mercury Sable LS PremiumFACTORY OEM SERVICE PROCEDURE

Test G: Powertrain 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.
  1. Turn ignition switch to LOCK position. Disconnect Powertrain Control Module (PCM) 104-pin harness connector C175. See Fig 1. PCM harness connector is located in left rear of engine compartment. 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.
  2. Connect PCM harness connector C175. 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 PCM: NO RESPONSE ON CKT914 (BUS +), go to next step. If WDS or NGS tester does not respond with PCM: NO RESPONSE ON CKT914 (BUS +), go to step  8.
  3. Turn ignition switch to LOCK position. Disconnect WDS or NGS tester. Disconnect PCM harness connector C175. Measure resistance between PCM harness connector C175 terminal No. 16 and DLC terminal No. 2 (Tan/Orange wire). See Figure and Fig 1 . See WIRING DIAGRAMS . If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, test system for normal operation.
  4. Disconnect in-line 16-pin harness connector C145. See Figure. In-line harness connector C145 is located in right rear of engine compartment. 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. After repair, test system for normal operation.
  5. Measure resistance between male half of in-line harness connector C145 terminal No. 1 and DLC terminal No. 2 (Tan/Orange wire). See Figure and Figure . See WIRING DIAGRAMS . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open circuit in Tan/Orange wire between male half of in-line harness connector C145 and DLC. After repair, test system for normal operation.
  6. Connect in-line harness connector C145. Disconnect in-line 12-pin harness connector C1046. See Fig 2. In-line harness connector C1046 is located in left rear of engine compartment. 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.
  7. Measure resistance between female half of in-line harness connector C1046 terminal No. 2 and DLC terminal No. 2 (Tan/Orange wire). See Figure and Fig 2 . See WIRING DIAGRAMS . If resistance is 5 ohms or less, repair open circuit in Tan/Orange wire between male in-line harness connector C1046 and PCM. If resistance is greater than 5 ohms, repair open circuit in Tan/Orange wire between in-line female harness connector C1046 and in-line female harness connector C145. After repair, test system for normal operation.
  8. Turn ignition switch to LOCK position. Disconnect WDS or NGS tester. Disconnect PCM harness connector C175. Measure resistance between PCM harness connector C175 terminal No. 15 and DLC terminal No. 10 (Pink/Light Blue wire). See Figure and Fig 1 . See WIRING DIAGRAMS . If resistance is greater than 5 ohms, go to next step. If resistance is 5 ohms or less, replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. After repair, test system for normal operation.
  9. Disconnect in-line 16-pin in-line harness connector C145. See Figure. In-line harness connector C145 is located in right rear of engine compartment. 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. After repair, test system for normal operation.
  10. Measure resistance between male half of in-line harness connector C145 terminal No. 5 and DLC terminal No. 10 (Pink/Light Blue wire). See Figure and Figure . See WIRING DIAGRAMS . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, repair open circuit in Pink/Light Blue wire between in-line harness connector C145 and DLC. After repair, test system for normal operation.
  11. Connect in-line harness connector C145. Disconnect in-line 12-pin harness connector C1046. See Fig 2. In-line harness connector C1046 is located in left rear of engine compartment. 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.
  12. Measure resistance between female half of in-line harness connector C1046 terminal No. 3 and DLC terminal No. 10 (Pink/Light Blue wire). See Figure and Fig 2 . See WIRING DIAGRAMS . If resistance is 5 ohms or less, repair open circuit in Pink/Light Blue wire between male half of in-line harness connector C1046 and PCM. If resistance is greater than 5 ohms, repair open circuit in Pink/Light Blue wire between female half of in-line harness connector C145 and female half of in-line harness connector C1046. After repair, clear DTCs and test system for normal operation.
Fig 1: Identifying Powertrain Control Module Harness Connector C175 Terminals
G96F31315Courtesy of FORD MOTOR CO.
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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.