Module Communications Network: Diagnosis Mercury Villager II

SELF-DIAGNOSTIC SYSTEM

Note. Tests included in this article are written specifically for New Generation Star (NGS) tester functionality. Other OBD II-compatible scan tools may be used, but may not be equipped with equal test function capabilities. Refer to scan tool manufacturer's instructions.

INSPECTION & VERIFICATION

1. Verify customer's original problem by operating system in question. Inspect vehicle for any obvious electrical component, wiring or connector damage. Inspect connectors for loose, damaged or corroded terminals. Check related fuses for system in question.
2. If problem is still present after performing inspection, connect New Generation Star (NGS) tester to appropriate Data Link Connector (DLC). DLC C2018 is for OBDII diagnostics and power to NGS. DLC C252 is for all module diagnostics. DLC C2018 is located below driver's side of instrument panel, to right of steering column. DLC C252 is located below driver's side of instrument panel, to left of steering column above fuse junction panel. Select vehicle to be tested from NGS tester menu. If NGS tester does not communicate with vehicle, ensure program card is properly installed. Check NGS tester cable connections and ensure ignition is on. If NGS tester still does not communicate with vehicle and NGS does not power up, go to «TEST E: NO MODULE/NETWORK COMMUNICATION & NO POWER TO DLC C2018»(ref-8436-S31590826162000082900000) under SYMPTOM TESTS. If NGS tester still does not communicate with vehicle and NGS powers up, go to «TEST D: NO MODULE/NETWORK COMMUNICATION & UNABLE TO COMMUNICATE WITH ANY MODULE»(ref-8436-S05220108332000082900000) under SYMPTOM TESTS. If NGS tester communicates with vehicle, perform system pre-check. See «SYSTEM PRE-CHECK - CHECKING COMMUNICATIONS WITH ALL MODULES»(ref-8436-S33722041692000082900000) .

RETRIEVING DIAGNOSTIC TROUBLE CODES

All Diagnostic Trouble Codes (DTC) for ABS and air bag are retrieved using flash codes. For description of ABS DTCs, see DIAGNOSTIC TROUBLE CODE INDEX (ABS CONTROL MODULE). For diagnosis of air bag restraint system DTCs, see AIR BAG SERVICE & REPAIR MANUAL, DOMESTIC & IMPORTED MODELS. PCM and TCM DTC retrieval and diagnosis is covered in appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE and ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.

SYMPTOM TESTS

Note. Tests included in this article are written specifically for New Generation Star (NGS) tester functionality. Other OBD II-compatible scan tools may be used, but may not be equipped with equal test function capabilities. Refer to scan tool manufacturer's instructions.

Note. Always check module power and ground circuits prior to replacing a control module. See DATA LINK CONNECTORS, GROUND DISTRIBUTION or POWER DISTRIBUTION article in WIRING DIAGRAMS.

SYMPTOM INDEX

TEST A: ANTI-LOCK BRAKE CONTROL MODULE DOES NOT RESPOND TO SCAN TOOL

1. Turn ignition off. Connect New Generation Star (NGS) tester to Data Link Connector (DLC) C252. DLC C252 is located below driver's side of instrument panel, to left of steering column, above fuse junction panel. Disconnect ABS control module connector C249, located behind center of dash. Inspect connector for loose, damaged or corroded terminals. Repair connector as necessary and retest system for normal operation. Measure resistance of Yellow/Red wire between terminal No. 22 at ABS control module connector and terminal No. 1 at DLC C252. (Scheme 1)and (Scheme 2). If resistance is less than 5 ohms, go to step 3. If resistance is 5 ohms or more, go to next step.
2. Measure resistance of Yellow/Red wire between female side of in-line connector C170 terminal No. 51 and DLC C252 terminal No. 1. In-line connector C170 is located behind left side of dash above fuse junction panel. (Scheme 3) If resistance is less than 5 ohms, repair open in Yellow/Red wire between ABS control module connector C249 and in-line connector C170. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Red wire between in-line connector C170 and DLC C252. Retest system.
3. Measure resistance of Yellow/Black wire between terminal No. 11 at ABS control module connector C249 and terminal No. 2 at DLC C252. If resistance is less than 5 ohms, replace ABS control module. Retest system. If resistance is 5 ohms or more, go to next step.
4. Measure resistance of Yellow/Black wire between female side of in-line connector C170 terminal No. 63 and DLC C252 terminal No. 2. In-line connector C170 is located behind left side of dash, above fuse junction panel. (Scheme 3) If resistance is less than 5 ohms, repair open in Yellow/Black wire between ABS control module connector C249 and in-line connector C170. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Black wire between in-line connector C170 and DLC C252. Retest system.

Scheme 1

Scheme 2

Scheme 3

TEST B: POWERTRAIN CONTROL MODULE DOES NOT RESPOND TO SCAN TOOL

Note. If test results indicate PCM is faulty, always check for engine performance-related DTCs prior to replacing PCM. If any DTCs are present, service DTCs as necessary and retest. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

1. Turn ignition off. Remove NGS tester. Disconnect PCM. Connector is located behind glove box. Inspect connector for loose, damaged or corroded terminals. Repair connector as necessary and retest system for normal operation. If connector is okay, measure resistance of Yellow/Red wire between terminal No. 74 at PCM connector and terminal No. 1 at Data Link Connector (DLC) C252. (Scheme 2)and (Scheme 4). If resistance is less than 5 ohms, go to step 3. If resistance is 5 ohms or more, go to next step.
2. Measure resistance of Yellow/Red wire between female side of in-line connector C272 terminal No. 2 and DLC C252 terminal No. 1. In-line connector C272 is located behind center top of dash. (Scheme 5) If resistance is less than 5 ohms, repair open in Yellow/Red wire between PCM connector and in-line connector C272. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Red wire between in-line connector C272 and DLC C252. Retest system.
3. Measure resistance of Yellow/Black wire between terminal No. 75 at PCM connector and terminal No. 2 at DLC C252. If resistance is less than 5 ohms, diagnose engine control system. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE and perform PCM system test. If resistance is 5 ohms or more, go to next step.
4. Measure resistance of Yellow/Black wire between female side of in-line connector C272 terminal No. 5 and DLC C252 terminal No. 2. In-line connector C272 is located behind center top of dash. (Scheme 5) If resistance is less than 5 ohms, repair open in Yellow/Black wire between PCM connector and in-line connector C272. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Black wire between in-line connector C272 and DLC C252. Retest system.

Scheme 4

Scheme 5

TEST C: TRANSMISSION CONTROL MODULE DOES NOT RESPOND TO SCAN TOOL

1. Turn ignition off. Remove NGS tester. Disconnect TCM. Connector is located behind instrument cluster. Inspect connector for loose, damaged or corroded terminals. Repair connector as necessary and retest system for normal operation. If connector is okay, measure resistance of Yellow/Red wire between terminal No. 6 at TCM connector C277B and terminal No. 1 of DLC C252. (Scheme 2)and (Scheme 6). If resistance is less than 5 ohms, go to step 3. If resistance is 5 ohms or more, go to next step.
2. Measure resistance of Yellow/Red wire between male side of in-line connector C255 terminal No. 4 and DLC C252 terminal No. 1. In-line connector C255 is located behind instrument cluster. (Scheme 7) If resistance is less than 5 ohms, repair open in Yellow/Red wire between TCM connector C277B and in-line connector C255. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Red wire between in-line connector C255 and DLC C252. Retest system.
3. Measure resistance of Yellow/Black wire between terminal No. 7 at TCM connector C277B and terminal No. 2 at DLC C252. If resistance is less than 5 ohms, replace TCM. Retest system. If resistance is 5 ohms or more, go to next step.
4. Measure resistance of Yellow/Black wire between male side of in-line connector C255 terminal No. 9 and DLC C252 terminal No. 2. In-line connector C255 is located behind instrument cluster. (Scheme 7) If resistance is less than 5 ohms, repair open in Yellow/Black wire between TCM connector C277B and in-line connector C255. Retest system. If resistance is 5 ohms or more, repair open in Yellow/Black wire between in-line connector C255 and DLC C252. Retest system.

Scheme 6

Scheme 7

TEST D: NO MODULE/NETWORK COMMUNICATION - UNABLE TO COMMUNICATE WITH ANY MODULE

1. Turn ignition off. Remove NGS tester. Inspect NGS tester connector for loose, damaged or corroded terminals. Repair connector as necessary and retest system for normal operation. If connector is okay, go to next step.
2. Inspect Data Link Connector (DLC) C252 for physical damage, bent terminals or corrosion. C252 is located below driver's side of instrument panel, to left of steering column above fuse junction panel. Repair connector as necessary and retest system for normal operation. If connector is okay, go to next step.
3. Disconnect TCM. Connector is located behind instrument cluster. Inspect connector for loose, damaged or corroded terminals. Repair connector as necessary and retest system for normal operation. If connector is okay, measure resistance of Yellow/Red wire between terminal No. 6 at TCM connector C277B and terminal No. 1 of DLC C252. (Scheme 2)and (Scheme 6). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Yellow/Red wire.
4. Measure resistance of Yellow/Black wire between terminal No. 7 at TCM connector C277B and terminal No. 2 at DLC C252. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Yellow/Black wire.
5. Connect NGS tester to Data Link Connector (DLC) C252. Turn ignition on. Run DIAGNOSTIC TEST MODE RESULTS for PCM. If the results are LINK COMMUNICATION ERROR, MODULE NOT RESPONDING, CHECK IGNITION STATUS, or CHECK CABLE (DDL ADAPTER) CONNECTIONS, go to next step. If results are not as listed, replace TCM. Retest system.
6. Turn ignition off. Disconnect ABS control module connector C249, located behind center of dash. Turn ignition on. Run DIAGNOSTIC TEST MODE RESULTS for PCM. If the results are LINK COMMUNICATION ERROR, MODULE NOT RESPONDING, CHECK IGNITION STATUS, or CHECK CABLE (DDL ADAPTER) CONNECTIONS, go to next step. If results are not as listed, replace ABS control module. Retest system.
7. Turn ignition off. Deactivate air bag system. See AIR BAG RESTRAINT SYSTEMS - VILLAGER article. Disconnect air bag diagnostic monitor. Air bag diagnostic monitor is located in bottom of center console. Turn ignition on. Run DIAGNOSTIC TEST MODE RESULTS for PCM. If the results are LINK COMMUNICATION ERROR, MODULE NOT RESPONDING, CHECK IGNITION STATUS, or CHECK CABLE (DDL ADAPTER) CONNECTIONS, go to next step. If results are not as listed, replace air bag diagnostic monitor. Retest system.
8. Turn ignition off. Disconnect PCM connector. PCM is located behind glove box. Turn ignition on. Measure voltage between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If voltage is present, go to step 24. If no voltage is present, go to next step.
9. Measure voltage between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If voltage is present, go to step 20. If no voltage is present, go to next step.
10. Turn ignition off. Measure resistance between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If resistance is greater than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, go to step 16.
11. Measure resistance between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If resistance is greater than 10 k/ohms, diagnose engine control system. See appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE. If resistance is 10 k/ohms or less, go to next step.
12. Disconnect in-line 84-pin connector C170. In-line connector C170 is located behind left side of dash above fuse junction panel. Measure resistance between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Black wire between in-line connector C170 and ABS control module. ABS control module is located behind center of dash. If resistance is 10 k/ohms or less, go to next step.
13. Disconnect in-line 16-pin connector C255. In-line connector C255 is located behind instrument cluster. Measure resistance between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Black wire between in-line connector C255 and TCM. TCM is located behind instrument cluster. If resistance is 10 k/ohms or less, go to next step.
14. Disconnect in-line 12-pin connector C2021. In-line connector C2021 is located behind center top of dash. Measure resistance between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Black wire between in-line connector C2021 and air bag diagnostic monitor. Air bag diagnostic monitor is located in bottom of center console. If resistance is 10 k/ohms or less, go to next step.
15. Disconnect in-line 6-pin connector C272. In-line connector C272 is located behind center top of dash. Measure resistance between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Black wire between in-line connector C272 and PCM. PCM is located behind glove box. If resistance is 10 k/ohms or less, repair short to ground in Yellow/Black wire between in-line connector C272, in-line connector C2021, in-line connector C255, in-line connector C170 and DLC C252.
16. Disconnect in-line 84-pin connector C170. In-line connector C170 is located behind left side of dash above fuse junction panel. Measure resistance between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Red wire between in-line connector C170 and ABS control module. ABS control module is located behind center of dash. If resistance is 10 k/ohms or less, go to next step.
17. Disconnect in-line 16-pin connector C255. In-line connector C255 is located behind instrument cluster. Measure resistance between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Red wire between in-line connector C255 and TCM. TCM is located behind instrument cluster. If resistance is 10 k/ohms or less, go to next step.
18. Disconnect in-line 12-pin connector C2021. In-line connector C2021 is located behind center top of dash. Measure resistance between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Red wire between in-line connector C2021 and air bag diagnostic monitor. Air bag diagnostic monitor is located in bottom of center console. If resistance is 10 k/ohms or less, go to next step.
19. Disconnect in-line 6-pin connector C272. In-line connector C272 is located behind center top of dash. Measure resistance between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If resistance is greater than 10 k/ohms, repair short to ground in Yellow/Red wire between in-line connector C272 and PCM. PCM is located behind glove box. If resistance is 10 k/ohms or less, repair short to ground in Yellow/Red wire between in-line connector C272, in-line connector C2021, in-line connector C255, in-line connector C170 and DLC C252.
20. Disconnect in-line 84-pin connector C170. In-line connector C170 is located behind left side of dash, above fuse junction panel. Measure voltage between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If voltage is zero volts, repair short to voltage in Yellow/Black wire between in-line connector C170 and ABS control module. ABS control module is located behind center of dash. If voltage is present, go to next step.
21. Disconnect in-line 16-pin connector C255. In-line connector C255 is located behind instrument cluster. Measure voltage between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If voltage is zero volts, repair short to voltage in Yellow/Black wire between in-line connector C255 and TCM. TCM is located behind instrument cluster. If voltage is present, go to next step.
22. Disconnect in-line 12-pin connector C2021. In-line connector C2021 is located behind center top of dash. Measure voltage between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If voltage is zero volts, repair short to voltage in Yellow/Black wire between in-line connector C2021 and air bag diagnostic monitor. Air bag diagnostic monitor is located in bottom of center console. If voltage is present, go to next step.
23. Disconnect in-line 6-pin connector C272. In-line connector C272 is located behind center top of dash. Measure voltage between ground and DLC C252 terminal No. 2 (Yellow/Black wire). If voltage is zero volts, repair short to voltage in Yellow/Black wire between in-line connector C272 and PCM. PCM is located behind glove box. If voltage is present, repair short to voltage in Yellow/Black wire between in-line connector C272, in-line connector C2021, in-line connector C255, in-line connector C170 and DLC C252.
24. Disconnect in-line 84-pin connector C170. In-line connector C170 is located behind left side of dash, above fuse junction panel. Measure voltage between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If voltage is zero volts, repair short to voltage in Yellow/Red wire between in-line connector C170 and ABS control module. ABS control module is located behind center of dash. If voltage is present, go to next step.
25. Disconnect in-line 16-pin connector C255. In-line connector C255 is located behind instrument cluster. Measure voltage between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If voltage is zero volts, repair short to voltage in Yellow/Red wire between in-line connector C255 and TCM. TCM is located behind instrument cluster. If voltage is present, go to next step.
26. Disconnect in-line 12-pin connector C2021. In-line connector C2021 is located behind center top of dash. Measure voltage between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If voltage is zero volts, repair short to voltage in Yellow/Red wire between in-line connector C2021 and air bag diagnostic monitor. Air bag diagnostic monitor is located in bottom of center console. If voltage is present, go to next step.
27. Disconnect in-line 6-pin connector C272. In-line connector C272 is located behind center top of dash. Measure voltage between ground and DLC C252 terminal No. 1 (Yellow/Red wire). If voltage is zero volts, repair short to voltage in Yellow/Red wire between in-line connector C272 and PCM. If voltage is present, repair short to voltage in Yellow/Red wire between in-line connector C272, in-line connector C2021, in-line connector C255, in-line connector C170 and DLC C252.

TEST E: NO MODULE/NETWORK COMMUNICATION - NO POWER TO DLC C2018

1. Inspect NGS tester connector for loose, damaged or corroded terminals. Repair connector as necessary and retest system for normal operation. If connector is okay, go to next step.
2. Turn ignition off. Inspect Data Link Connector (DLC) C2018 for physical damage, bent terminals or corrosion. DLC C2018 is located below driver's side of instrument panel, to right of steering column. Repair as necessary and retest system for normal operation. If connector is okay, go to next step.
3. Measure voltage between ground and terminal No. 16 (Red wire) at DLC. (Scheme 8) If voltage is greater than 10 volts, go to next step. If voltage is 10 volts or less, repair Red wire between instrument panel fuse block and DLC C2018. Retest system for normal operation.
4. Measure resistance between ground and terminals No. 4 (Black wire) and No. 5 (Black/Red wire) at DLC. If both resistance readings are less than 5 ohms, repair or replace NGS tester. Retest system for normal operation. If any resistance reading is 5 ohms or more, repair open in Black wire or Black/Red wire between ground and DLC C2018. Retest system for normal operation.

Scheme 8

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE INDEX (ABS CONTROL MODULE)