Possible Causes
WARNING: This page is about a different car, the 2004 Ford Econoline. 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, faulty RCM or low battery voltage.
- Check RCM connector C310A & pin for damage
Turn ignition switch to OFF position. Disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Access and disconnect RCM connector C310A. See RESTRAINTS CONTROL MODULE (RCM) under REMOVAL & INSTALLATION. Inspect both harness side and component side of RCM connector C310A, terminal No. 11 for damage, corrosion or dirt. See Figure & Figure . If no problems are found with connector or component, go to next step. If problems are found, replace/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) 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 (Red/White wire, circuit No. 937). If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair open in Red/White wire. Retest communication to RCM. Activate air bag system. - Check ground circuit for open
Turn ignition switch to OFF position. Measure resistance between ground and harness side of RCM connector C310A, terminal No. 16 (Black/Light Blue wire, circuit No. 1203). If resistance is less than 5 ohms, go to next step. If resistance is more than 5 ohms, repair open in Black/Light Blue wire. 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.NOTE: Ensure all air bag system simulators, sensor electrical connectors and RCM electrical connectors are connected prior to carrying out on-demand self-test, or erroneous faults may be set. - 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.