When the CEL does not turn on, it could be a fault with the wiring circuit, a bad bulb or a faulty ECM.
When scan tool cannot communicate with the ECM, it coudl be a faulty ECM, wiring fault, missing power supply or the scan tool is not compatible.
Remove the instrument cluster to check the CEL bulb. Test for continuity of wire between the Check Connector and TCCS ECU terminal B4, Green/Red wire.
Saturday, January 8th, 2011 AT 5:01 PM