Re: Any Ford techs here
Maybe this should help
DIAGNOSTIC TROUBLE CODE 42: LH RADIATOR PRIMARY CRASH SENSOR FEED/RETURN CIRCUIT OPEN
NOTE:
Use Rotunda 73 Digital Multimeter 105-00051 or equivalent to perform electrical pinpoint tests.
Normal Operation
The voltage at Pin 15 and Circuit 619 (PK/W) is set by the air bag diagnostic monitor to be slightly less than battery voltage. Circuit 619 is connected to Circuit 625 (Y/LG) inside the LH radiator front air bag sensor and bracket. Therefore, the voltage at Circuit 625 and air bag diagnostic monitor Pin 23 should be the same as the voltage at air bag diagnostic monitor Pin 15.
The air bag diagnostic monitor periodically pulls the voltage at Pin 15 low to verify the connection to Pin 23. If the voltage at Pin 23 does not pull low as a result of this test, air bag diagnostic monitor will store in memory and flash out on the air bag indicator a DTC 42. If the connection between Pins 15 and 23 is later serviced, the next ignition switch cycle will produce a DTC 82 (or a higher priority DTC if one exists).
Possible Causes
Failure to get low voltage at Pin 23 during the test can be caused by:
l An open circuit in the wiring harness in either Circuit 619 (PK/W) or Circuit 625 (Y/LG).
l An open circuit inside left radiator front air bag sensor and bracket across Circuit 619 (PK/W) or Circuit 625 (Y/LG).
l A short to battery or ignition voltage in any of the Circuits 617 (PK/O), 619 (PK/W), 624 (Y/W), 625 (Y/LG).
