Module Communications Network: Diagnosis Ford Focus II

Inspection and Verification

1. Verify the customer concern.
2. Visually inspect for obvious signs of electrical damage. VISUAL INSPECTION CHART Electrical Central junction box (CJB) fuse 48 (10A) Wiring harness Connector(s)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, connect the diagnostic tool to the data link connector (DLC) and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does not communicate with the vehicle: check that the program card is correctly installed. check the connections to the vehicle. check the ignition switch position.
5. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
6. GO to «PINPOINT TEST PC»(ref-255415-S07201827822007053100000) .

PINPOINT TEST PC: RUN THE DATA LINK DIAGNOSTICS TEST

1. PC1 DATA LINK DIAGNOSTICS TEST Carry out the diagnostic tool data link test. Does the system pass the data link test? Yes : The test passed. RETURN to the Symptom Chart of the article for the module in question. No : If ISO circuit faults; all electronic control units no response/not equipped, GO to «PINPOINT TEST E»(ref-255415-S37221152512007053100000) . If CAN circuit faults; all electronic control units no response/not equipped, GO to «PINPOINT TEST F»(ref-255415-S18569076622007053100000) . If no response from the diagnostic tool, GO to «PINPOINT TEST G»(ref-255415-S11791251412007053100000) .

Symptom Chart

SYMPTOM CHART

PINPOINT TEST A: THE ANTI-LOCK BRAKE SYSTEM (ABS) MODULE DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

Scheme 1

Scheme 2

1. A1 CHECK THE CAN CIRCUITS BETWEEN THE DLC C251 AND THE ABS MODULE FOR AN OPEN Key in OFF position. Disconnect: ABS Module with stability assist C135 (if equipped). Disconnect: ABS Module C155 (if equipped). For vehicles equipped with stability assist, measure the resistance between the ABS module C135-11, circuit 4-EC9A (GY), harness side and the DLC C251-6, circuit 4-EC7E (GY/RD), harness side; and between the ABS module C135-15, circuit 5-EC9A (BU), harness side and the DLC C251-14, circuit 5-EC7E (BU/RD), harness side. For ABS only equipped vehicles, measure the resistance between the ABS module C155-23, circuit 4-EC9A (GY), harness side and the DLC C251-6, circuit 4-EC7E (GY/RD), harness side; and between the ABS module C155-21, circuit 5-EC9A (BU), harness side and the DLC C251-14, circuit 5-EC7E (BU/RD), harness side. Are the resistances less than 5 ohms? Yes : GO to A2 . No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2. A2 CHECK FOR CORRECT ABS MODULE OPERATION Disconnect all the ABS module connectors. Check for: corrosion pushed-out pins Connect all the ABS control module connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new ABS module. REFER to «VEHICLE DYNAMIC SYSTEMS»(ref-255409) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

PINPOINT TEST B: THE POWERTRAIN CONTROL MODULE (PCM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

Scheme 3

1. B1 CHECK THE CAN CIRCUITS BETWEEN THE DLC AND THE PCM FOR AN OPEN Key in OFF position. Disconnect: PCM C175b. Measure the resistance between the PCM C175b-11, circuit 4-EC7 (GY/RD), harness side and the DLC C251-66, circuit 4-EC7E (GY/RD), harness side; and between the PCM C175b-23, circuit 5-EC7 (BU/RD), harness side and the DLC C251-14, circuit 5-EC7E (BU/RD), harness side. Are the resistances less than 5 ohms? Yes : GO to B2 . No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2. B2 CHECK FOR CORRECT PCM OPERATION Disconnect all PCM connectors. Check for: corrosion pushed-out pins Connect all PCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-255389) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

PINPOINT TEST C: THE INSTRUMENT CLUSTER DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

Scheme 4

1. C1 CHECK THE CAN CIRCUITS BETWEEN THE DLC AND THE INSTRUMENT CLUSTER FOR AN OPEN Key in OFF position. Disconnect: Instrument Cluster C2220. Measure the resistance between the instrument cluster C2220-31, circuit 4-EC7B (GY/RD), harness side and the DLC C251-6, circuit 4-EC7E (GY/RD), harness side; and between the instrument cluster C2220-15, circuit 5-EC7B (BU/RD), harness side and the DLC C251-14, circuit 5-EC7E (BU/RD), harness side. Are the resistances less than 5 ohms? Yes : GO to C2 . No : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2. C2 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION Disconnect all instrument cluster connectors. Check for: corrosion pushed-out pins Connect all instrument cluster connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new instrument cluster. REFER to «INSTRUMENT CLUSTER»(ref-255408) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

PINPOINT TEST D: THE RESTRAINT CONTROL MODULE (RCM) DOES NOT RESPOND TO THE DIAGNOSTIC TOOL

Scheme 5

1. D1 CHECK THE CAN CIRCUITS BETWEEN THE RCM AND THE DLC FOR AN OPEN Key in OFF position. Depower the air bag system. Refer to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . Disconnect: RCM C2041b. Measure the resistance between the RCM C2041b-19, circuit 4-EC18 (GY/BK), harness side and the DLC C251-6, circuit 4-EC7E (GY/RD), harness side; and between the RCM C2041b-20, circuit 5-EC18 (BU/BK), harness side and the DLC C251-14, circuit 5-EC7E (BU/RD), harness side. Are the resistances less than 5 ohms? Yes : GO to D2 . No : REPAIR the circuit in question. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2. D2 CHECK FOR CORRECT RCM OPERATION Disconnect all the RCM connectors. Check for: corrosion pushed-out pins Connect all the RCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new RCM. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

PINPOINT TEST E: NO INTERNATIONAL STANDARDS ORGANIZATION (ISO) 9141 NETWORK COMMUNICATION

Scheme 6

Scheme 7

Scheme 8

1. E1 CHECK THE ISO 9141 CIRCUIT BETWEEN THE GEM AND THE DLC FOR AN OPEN Key in OFF position. Disconnect: GEM C201d. Measure the resistance between the GEM C201d-16, circuit 8-EE9 (WH/GN), harness side and the DLC C251-7, circuit 8-EE9 (WH/GN), harness side. Is the resistance less than 5 ohms? Yes : GO to E2 . No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2. E2 CHECK THE ISO 9141 NETWORK FOR A SHORT TO GROUND Measure the resistance between the DLC C251-7, circuit 8-EE9 (WH/GN), harness side and ground. Is the resistance greater than 10,000 ohms? Yes : GO to E3 . No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
3. E3 CHECK THE ISO CIRCUIT FOR A SHORT TO VOLTAGE Key in ON position. Measure the voltage between the DLC C251-7, circuit 8-EE9 (WH/GN), harness side and ground. Is any voltage indicated? Yes : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : GO to E4 .
4. E4 CHECK FOR CORRECT GEM OPERATION Disconnect all GEM connectors. Check for: corrosion pushed-out pins Connect all GEM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new GEM. REFER to «MULTIFUNCTION ELECTRONIC MODULES»(ref-255417) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

PINPOINT TEST F: NO CONTROLLER AREA NETWORK (CAN) COMMUNICATION

Scheme 9

Scheme 10

Scheme 11

Scheme 12

Scheme 13

1. F1 CHECK THE CAN CIRCUITS BETWEEN THE RCM AND THE DLC FOR AN OPEN Key in OFF position. Depower the air bag system. Refer to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . Disconnect: RCM C2041b. Measure the resistance between the RCM C2041b-19, circuit 4-EC18 (GY/BK), harness side and the DLC C251-6, circuit 4-EC7E (GY/RD), harness side; and between the RCM C2041b-20, circuit 5-EC18 (BU/BK), harness side and the DLC C251-14, circuit 5-EC7E (BU/RD), harness side. Are the resistances less than 5 ohms? Yes : GO to F2 . No : REPAIR the circuit in question. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2. F2 CHECK THE CAN WITH THE RCM DISCONNECTED Key in ON position. Enter the following diagnostic mode on the diagnostic tool: Data Link Diagnostics Test. Does the diagnostic tool indicate system passed? Yes : GO to F13 . No : GO to F3 .
3. F3 CHECK THE CAN WITH THE OCCUPANT CLASSIFICATION SENSOR DISCONNECTED Key in OFF position. Connect: RCM C2041b. Disconnect: Occupant Classification Sensor C3043. Key in ON position. Enter the following diagnostic mode on the diagnostic tool: Data Link Diagnostics Test. Does the diagnostic tool indicate system passed? Yes : GO to F14 . No : GO to F4 .
4. F4 CHECK THE CAN WITH THE ABS MODULE DISCONNECTED Key in OFF position. Connect: Occupant Classification Sensor C3043. Disconnect: ABS Module C135 (with stability assist) (if equipped). Disconnect: ABS Module C155 (ABS only) (if equipped). Key in ON position. Enter the following diagnostic mode on the diagnostic tool: Data Link Diagnostics Test. Does the diagnostic tool indicate system passed? Yes : GO to F12 . No : GO to F5 .
5. F5 CHECK THE CAN CIRCUITS BETWEEN THE DLC AND THE INSTRUMENT CLUSTER FOR AN OPEN Key in OFF position. Connect: ABS Module C135 (with stability assist) (if equipped). Connect: ABS Module C155 (ABS only) (if equipped). Disconnect: Instrument Cluster C2220. Measure the resistance between the DLC C251-6, circuit 4-EC7E (GY/RD), harness side and the instrument cluster C2220-31, circuit 4-EC7B (GY/RD), harness side; and between the DLC C251-14, circuit 5-EC7E (BU/RD), harness side and the instrument cluster C2220-15, circuit 5-EC7B (BU/RD), harness side. Are the resistances less than 5 ohms? Yes : GO to F6 . No : REPAIR the circuit in question. CLEAR the DTCs. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . REPEAT the self-test. CARRY OUT the data link diagnostics test.
6. F6 CHECK THE CAN CIRCUITS BETWEEN THE DLC AND THE PCM FOR AN OPEN Key in OFF position. Disconnect: PCM C175b. Measure the resistance between the PCM C175b-11, circuit 4-EC7 (GY/RD), harness side and the DLC C251-6, circuit 4-EC7E (GY/RD), harness side; and between the PCM C175b-23, circuit 5-EC7 (BU/RD), harness side and the DLC C251-14, circuit 5-EC7E (BU/RD), harness side. Are the resistances less than 5 ohms? Yes : GO to F7 . No : REPAIR the circuit in question. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
7. F7 CHECK THE CAN FOR A SHORT TO VOLTAGE Disconnect: ABS Module C135 (with stability assist) (if equipped). Disconnect: ABS Module C155 (ABS only) (if equipped). Disconnect: Occupant Classification Sensor C3043. Disconnect: RCM C2041b. Key in ON position. Measure the voltage between the DLC C251-6, circuit 4-EC7E (GY/RD), harness side and ground; and between the DLC C251-14, circuit 5-EC7E (BU/RD), harness side and ground. Is any voltage indicated? Yes : REPAIR the circuit in question. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : GO to F8 .
8. F8 CHECK THE CAN FOR A SHORT TO GROUND Key in OFF position. Measure the resistance between the DLC C251-6, circuit 4-EC7E (GY/RD), harness side and ground; and between the DLC C251-14, circuit 5-EC7E (BU/RD), harness side and ground. Are the resistances greater than 10,000 ohms? Yes : GO to F9 . No : REPAIR the circuit in question. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
9. F9 CHECK THE CAN WITH A SUBSTITUTED PCM Connect: Instrument Cluster C2220. Install a known good PCM. Key in ON position. Enter the following diagnostic mode on the diagnostic tool: Data Link Diagnostics Test. Does the diagnostic tool indicate system passed? Yes : GO to F10 . No : REINSTALL the original PCM. GO to F11 .
10. F10 CHECK FOR CORRECT PCM OPERATION Disconnect all PCM connectors. Check for: corrosion pushed-out pins Connect all PCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new PCM. REFER to «ELECTRONIC ENGINE CONTROLS»(ref-255389) . REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
11. F11 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION Disconnect all instrument cluster connectors. Check for: corrosion pushed-out pins Connect all instrument cluster connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new instrument cluster. REFER to «INSTRUMENT CLUSTER»(ref-255408) . REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
12. F12 CHECK FOR CORRECT ABS MODULE OPERATION Disconnect all the ABS module connectors. Check for: corrosion pushed-out pins Connect all the ABS control module connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new ABS module. REFER to «VEHICLE DYNAMIC SYSTEMS»(ref-255409) . REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
13. F13 CHECK FOR CORRECT RCM OPERATION Disconnect all the RCM connectors. Check for: corrosion pushed-out pins Connect all the RCM connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new RCM. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
14. F14 CHECK FOR CORRECT OCCUPANT CLASSIFICATION SENSOR OPERATION Disconnect all the occupant classification sensor connectors. Check for: corrosion pushed-out pins Connect all the occupant classification sensor connectors and make sure they seat correctly. Operate the system and verify the concern is still present. Is the concern still present? Yes : INSTALL a new occupant classification sensor. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test. No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. REPOWER the air bag system. REFER to «SUPPLEMENTAL RESTRAINT SYSTEM»(ref-255419) . CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.