Possible Causes
WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
A no communication with RCM fault could be caused by damaged wiring, terminals or connectors, a faulty DLC or faulty RCM.
- Check RCM connector & pin for damage
Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect connector C310A. Connect negative battery cable. Inspect both harness side and component side of RCM connector C310A, terminal No. 11 for damage, corrosion or dirt. See Figure . If no problem is found with connector or component, go to next step. If problems are found, repair RCM and/or connector as necessary. Retest communication to RCM. Activate air bag system. See ACTIVATING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. - Check DLC connector & pin for damage
Inspect DLC connector and terminal No. 7 (Light Blue/White wire, circuit No. 70) for damage, corrosion or dirt. See Fig 1 . If no problem is found with connector or terminal, go to next step. If problem is found, repair connector or terminal as necessary. Retest communication to RCM. Activate air bag system. - Check ignition circuit for open
Turn ignition switch to ON position. Measure voltage between ground and harness side of RCM connector C310A, terminal No. 12 (Gray/Yellow wire, circuit No. 1003). If voltage is 9-16 volts, go to next step. If voltage is not 9-16 volts, repair open in White/Yellow wire. See WIRING DIAGRAMS . Retest communication to RCM. Activate air bag system. - Check ground circuit for open
Turn ignition switch to OFF position. Measure resistance between sheet metal ground near RCM and harness side of RCM connector C310A, terminal No. 16 (Black/Orange wire, circuit No. 649). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair Black/Orange wire as necessary. Retest communication to RCM. Activate air bag system. - Check circuit for open
Measure resistance between harness side of RCM connector C310A, terminal No. 11 and DLC connector terminal No. 7 (Light Blue/White wire). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Light Blue/White wire. Retest communication to RCM. Activate air bag system. - Confirm RCM fault
Reconnect RCM connector C310A. Turn ignition switch to ON position. Perform on-demand-self-test. If scan tool can communicate with RCM during on-demand self-test, fault is corrected. Activate air bag system. If scan tool cannot communicate with RCM during on-demand self-test, replace RCM. Retest communication to RCM. Activate air bag system.