LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mercury >> 2000 >> Grand Marquis LS >> Repair and Diagnosis >> Accessories & Equipment >> Communication Devices >> Module Communications Network System >> System Tests >> Test J: No Module/Network Communications - SCP Network
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test J: No Module/Network Communications - SCP Network

NOTE: Powertrain Control Module (PCM), Electronic Automatic Temperature Control (EATC) module, Anti-Lock Brake System (ABS) control module, Passive Anti-Theft System (PATS) module and Natural Gas Vehicle Module (NGVM) (if equipped) are connected to bus.
NOTE: Depending on module configuration, with all modules connected and with ignition switch in RUN position or with engine running, 2-3 volts may be present at DLC terminals No. 2 (Tan/Orange wire) and No. 10 (Pink/Light Blue wire). These are the Standard Corporate Protocol (SCP) diagnostic communications network circuits.
  1. Check NGS tester terminals physical damage, bent terminals or corrosion. If problem does not exist, go to next step. If problem exists, repair as necessary and retest system.
  2. Turn ignition switch to LOCK position. Inspect Data Link Connector (DLC) for physical damage, bent terminals or corrosion. See Figure . If problem does not exist, go to next step. If problem exists, repair as necessary and retest system.
  3. Disconnect PCM harness connector C185. See Figure . Measure resistance in Tan/Orange wire between terminal No. 16 at PCM harness connector C185 and terminal No. 2 at DLC. See Figure and Figure . Also, measure resistance in Pink/Light Blue wire between terminal No. 15 at PCM harness connector C185 and terminal No. 10 at DLC. If both measurements are 5 ohms or less and PCM is the only module on bus, go to next step. If both measurements are 5 ohms or less and PCM is not the only module on bus, go to step  10 . If either measurement is greater than 5 ohms and PCM in the only module on bus, perform TEST G: POWERTRAIN CONTROL MODULE DOES NOT RESPOND TO SCAN TOOL  . If either measurement is greater than 5 ohms and PCM in not the only module on bus, repair open in Tan/Orange wire and/or Pink/Light Blue wire between PCM harness connector C185 and in-line harness connector C107. See Figure .
  4. Turn ignition switch to RUN position. Measure voltage at terminal No. 2 (Tan/Orange wire) at DLC. Also, measure voltage at terminal No. 10 (Pink/Light Blue wire) at DLC. If either measurement indicates more than 10 volts, go to step  7 . If both measurements do not indicate more than 10 volts, go to next step.
  5. Turn ignition switch to LOCK position. Disconnect in-line harness connector C103. See Figure . Turn ignition switch to RUN position. Measure voltage at terminal No. 2 (Tan/Orange wire) at DLC. Also, measure voltage at terminal No. 10 (Pink/Light Blue wire) at DLC. If either measurement indicates more than 10 volts, go to next step. If both measurements do not indicate more than 10 volts, repair short to voltage in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C103 and PCM.
  6. Turn ignition switch to LOCK position. Disconnect in-line harness connector C107. See Figure . Turn ignition switch to RUN position. Measure voltage at terminal No. 2 (Tan/Orange wire) at DLC. Also, measure voltage at terminal No. 10 (Pink/Light Blue wire) at DLC. If either measurement indicates more than 10 volts, repair short to voltage in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C107 and DLC. If both measurements do not indicate more than 10 volts, repair short to voltage in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C103 and in-line harness connector C107.
  7. Turn ignition switch to LOCK position. Measure resistance between ground and terminal No. 2 (Tan/Orange wire) at DLC. Also, measure resistance between ground and terminal No. 10 (Pink/Light Blue wire) at DLC. If either measurement is 10 k/ohms or less, go to next step. If both measurements are greater than 10 k/ohms, diagnose engine control system. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  8. Disconnect in-line harness connector C103. See Figure . Measure resistance between ground and terminal No. 2 (Tan/Orange wire) at DLC. Also, measure resistance between ground and terminal No. 10 (Pink/Light Blue wire) at DLC. If both measurements are less than 5 ohms, go to next step. If either measurement is 5 ohms or more, repair short to ground in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C107 and PCM.
  9. Disconnect in-line harness connector C107. See Figure . Measure resistance between ground and terminal No. 2 (Tan/Orange wire) at DLC. Also, measure resistance between ground and terminal No. 10 (Pink/Light Blue wire) at DLC. If both measurements are less than 5 ohms, repair short to ground in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C107 and DLC. If either measurement is 5 ohms or more, repair short to ground in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C103 and in-line harness connector C107.
  10. Turn ignition switch to RUN position. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 4 (Black wire) at DLC. Measure voltage between terminals No. 10 (Pink/Light Blue wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Pink/Light Blue wire) at DLC. If any measurement indicates zero voltage, go to next step. If all readings indicate voltage, diagnose engine control system. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  11. Turn ignition switch to LOCK position. Disconnect in-line harness connector C103. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 4 (Black wire) at DLC. Measure voltage between terminals No. 10 (Pink/Light Blue wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Pink/Light Blue wire) at DLC. If any measurement indicates zero voltage, go to next step. If all measurements indicate voltage, repair short to ground or voltage in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C103 and PCM.
  12. If vehicle is equipped with CNG fuel system, go to next step. If vehicle is not equipped with CNG fuel system, go to step  14 .
  13. Turn ignition switch to LOCK position. Disconnect Natural Gas Vehicle Module (NGVM) harness connector C124. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 4 (Black wire) at DLC. Measure voltage between terminals No. 10 (Pink/Light Blue wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Pink/Light Blue wire) at DLC. If any measurement indicates zero voltage, go to next step. If all measurements indicate voltage, diagnose engine control system. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
  14. If vehicle is equipped with anti-lock brakes, go to next step. If vehicle is not equipped with anti-lock brakes, go to step  16 .
  15. Turn ignition switch to LOCK position. Disconnect Anti-Lock Brake System (ABS) control module harness connector C162. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 4 (Black wire) at DLC. Measure voltage between terminals No. 10 (Pink/Light Blue wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Pink/Light Blue wire) at DLC. If any measurement indicates zero voltage, go to next step. If all measurements indicate voltage, replace ABS control module.
  16. If vehicle is equipped with passive anti-theft system, go to next step. If vehicle is not equipped with passive anti-theft system, go to step  18 .
  17. Turn ignition switch to LOCK position. Disconnect Passive Anti-Theft System (PATS) module harness connector C229. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 4 (Black wire) at DLC. Measure voltage between terminals No. 10 (Pink/Light Blue wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Pink/Light Blue wire) at DLC. If any measurement indicates zero voltage, go to next step. If all measurements indicate voltage, replace PATS module.
  18. If vehicle is equipped with electronic climate control, go to next step. If vehicle is not equipped with electronic climate control, go to step  20 .
  19. Turn ignition switch to LOCK position. Disconnect Electronic Automatic Temperature Control (EATC) module harness connector C227. See Figure . Turn ignition switch to RUN position. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 2 (Tan/Orange wire) and No. 4 (Black wire) at DLC. Measure voltage between terminals No. 10 (Pink/Light Blue wire) and No. 16 (Yellow/Black wire) at DLC. Measure voltage between terminals No. 4 (Black wire) and No. 10 (Pink/Light Blue wire) at DLC. If any measurement indicates zero voltage, go to next step. If all measurements indicate voltage, replace EATC module.
  20. Turn ignition switch to LOCK position. Disconnect in-line harness connector C103. See Figure . Turn ignition switch to RUN position. Measure voltage between ground and terminal No. 2 (Tan/Orange wire) at DLC. Measure voltage between ground and terminal No. 10 (Pink/Light Blue wire) at DLC. If either measurement is greater than 10 volts, go to next step. If both measurements are 10 volts or less, go to step  22 .
  21. Turn ignition switch to LOCK position. Disconnect in-line harness connector C107. See Figure . Turn ignition switch to RUN position. Measure voltage between ground and terminal No. 2 (Tan/Orange wire) at DLC. Measure voltage between ground and terminal No. 10 (Pink/Light Blue wire) at DLC. If either measurement indicates more than 10 volts, repair short to voltage in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C107, EATC module (if equipped), PATS module (if equipped) and DLC. If both measurements are not greater than 10 volts, repair short to voltage in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C103, NGVM (if equipped), ABS control module (if equipped), EVAC module (if equipped) and in-line harness connector C107.
  22. Turn ignition switch to LOCK position. Disconnect in-line harness connector C107. See Figure . Turn ignition switch to RUN position. Measure voltage between ground and terminal No. 2 (Tan/Orange wire) at DLC. Measure voltage between ground and terminal No. 10 (Pink/Light Blue wire) at DLC. If either measurement is less than 5 ohms, repair short to ground in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C107, EATC module (if equipped), PATS module (if equipped) and DLC. If both measurements are not less than 5 ohms, repair short to ground in Tan/Orange wire and/or Pink/Light Blue wire between in-line harness connector C103, NGVM (if equipped), ABS control module (if equipped), EVAC and fill connector (if equipped) and in-line harness connector C107.
scientia non olet · About LEMON Manuals