2003 Mercury Grand Marquis C1145 Code
 

2003 Merc GM has a C1145 ABS code which is illuminating the ABS light and the Trac Control light immediately upon startup. I have replaced the RF wheel hub assembly, which included a new sensor, with a motorcraft replacement and tried clearing the codes with my scan tool. No results, lights still on upon startup. I have checked all connectors and cleaned them all and have applied dieletric grease to them. I have voltage at the connector which is 11 volts with key in ignition and 13.4 V with the car running. I also have no continuity to ground so i believe the wiring is not at fault but i could be wrong. I know its not a serious issues but I would like to get it resolved. Any ideas on further troubleshooting would be greatly appreciated before i jump into it being the actual ABS module. Thank You!

Hello, Figs, and welcome to the Mercury Forums --
C1145 =
1. Bad Sensor.
2. Harness shorted or open.
3. Connector Faulty.
From your description of the problem, and the steps that you've already taken, it appears that the issue lies within the Speed Sensor itself -- rather than the Sensor Ring that's on the New Hub.
Sometimes the Sensor gets fouled with grease or debris, and just needs cleaning.
Good luck !

I have replaced the whole wheel hub assembly which came with a new motor craft wheel speed sensor. Im assuming it should be good. Any way i can check it out to see if it is working properly? Or check the Ohm value through the sensor itself? Really at a loss as I have made no strides into getting this problem taken care of. Thank you for any input you may have.

I rooted around in the Forums, and found this:
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Error code C1145 (ABS light on) is rather common, Ford has several TSB's out there for that.

Someone just told me that he spend hundreds of dollars in changing parts in order to get it fixed, and the light still comes on.

Here is the likely cause (don't have the complete TSB's yet, will follow up):
ISSUE:

The Anti-Lock Brake System (ABS) Malfunction Indicator Lamp (MIL) may illuminate on some vehicles. Diagnostic Trouble Codes (DTCs) C1145, C1148, C1155, C1158, C1233, and C1234 may be stored in memory.
This may be caused by a short due to water intrusion in the right or left front ABS wheel sensor harness connection(s).
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If all of the corrosion can't be removed from the Harness Connection, you may need to replace the connectors with new parts.
To clear any "stored memory" codes, disconnect BOTH battery terminals for at least ONE (1) Hour.
Keep us posted.