Ford Expedition without tach signal
Some 2007 Ford Expedition and Navigator vehicles built before 10/20/2006 may exhibit no tachometer signal, with instrument cluster lights on and engine running. After engine shutdown, this can be followed by a n-crank/no-start, with no communication from the powertrain control module (PCM). Diagnostic trouble code P1260 may also be present in the PCM memory (theft detected/vehicle immobilized).
Pinpoint which connector is the most likely source of the problem. Use a service tool to run a network test or any other link-based function (retrieving DTCs( to attempt communication with each of the standard HS-CAN modules (IC, restraint control module/RCM, anti-lock brake system/ABS, transmission control module/TCM and the PCM. If you are able to communicate with IC but fail with RCM, ABS, TCM and PCM modules, check both sides of C238 pins 62 and 63, HS-CAN circuits VDB04 (WH-BU) and VDB05 (WH) for loose or damaged terminals.
If you are able to communicate with IC and RCM but fail with ABS, TCM and PCM modules, check both sides of C212 pins 12 and 13.
If you are able to communicate with IC, RCM and ABS but fail with TCM and PCM modules, check both sides of C146, pins 20 and 21.
If you are able to communicate with IC, RCM, ABS and TCM but fail with the PCM module, check both sides of C146, pins 13 and 14.
If you are unable to communicate with any module, refer to the service manual for further diagnostics. If you are able to communicate with all modules, the problem may be intermittent, requiring inspection of all connectors.