Pinpoint Test I: The C-Cm Does Not Communicate With The Scan Tool
WARNING: This page is about a different car, the 2011 Lincoln MKT. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE:
Failure to disconnect the battery when instructed will result in false resistance readings. Refer to
BATTERY, BATTERY MOUNTING & BATTERY CABLES
article.
- I1 CHECK THE C-CM VOLTAGE SUPPLY CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect: C-CM C1582.
- Ignition ON.
- Measure the voltage between the C-CM C1582-1, circuit SBB15 (WH/RD), harness side and ground; and between the C-CM C1582-10, circuit CBB34 (VT/BN), harness side and ground.
- Are the voltages greater than 10 volts?
- Yes : GO to I2.
- No : VERIFY the Battery Junction Box (BJB) fuse 15 (15A) or Smart Junction Box (SJB) fuse 34 (5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the SYSTEM WIRING DIAGRAMS article to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool.
- I2 CHECK THE C-CM GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Measure the resistance between the C-CM C1582-3, circuit GD120 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
- Yes : GO to I3.
- No : REPAIR the circuit. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
- I3 CHECK THE HS-CAN CIRCUITS BETWEEN THE C-CM AND THE DLC FOR AN OPEN
- Measure the resistance between the C-CM C1582-8, circuit VDB04 (WH/BU), harness side and the DLC C251-6, circuit VDB04 (WH/BU), harness side.
- Measure the resistance between the C-CM C1582-7, circuit VDB05 (WH), harness side and the DLC C251-14, circuit VDB05 (WH), harness side.
- Are the resistances less than 5 ohms?
- Yes : CONNECT the negative battery cable. GO to I4.
- No : REPAIR the circuit in question. CONNECT the negative battery cable. CLEAR the DTCs. REPEAT the network test with the scan tool.
- I4 CHECK FOR CORRECT C-CM OPERATION
- Disconnect the C-CM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the C-CM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new C-CM. REFER to CRUISE CONTROL SYSTEM article. REPEAT the network test with the scan tool.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.