Starter Motor - Ground Circuit
WARNING: This page is about a different car, the 2008 Mercury Sable, 2008 Ford Taurus X, and 2008 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
A slow cranking condition can be caused by resistance in the ground or return portion of the cranking circuit. Check the voltage drop in the ground circuit as follows:
- Connect the 73III Automotive Meter positive lead to the starter motor housing (the connection must be clean and free of rust or grease). Connect the negative lead to the negative (-) battery terminal.
- Engage the remote starter switch and crank the engine. Read and record the voltage reading. The reading should be 0.2 volt or less.
- If the voltage drop is more than 0.2 volt, clean the negative cable connections at the battery, the body ground connections and the starter ground connection. Retest.
- If the voltage drop is greater than 0.2 volt, install a new cable. If the voltage reading is less than 0.2 volt and the engine still cranks slowly, install a new starter motor.