Voltage Drop Test (Motor Feed Circuit & Motor Ground Circuit)
Starter Motor - Motor Feed Circuit Voltage Drop Test1. This test is carried out to determine if slow cranking is caused by high resistance in the starter motor circuit wiring.
2. The voltage drop test can only be carried out with the starter motor on the vehicle.
3. Disconnect the fuel pump electrical connector.
4. Connect the positive lead of the 73 Digital Multimeter to the battery positive (+) post, and the negative lead to the starter solenoid M-terminal.
5. Connect a remote starter switch between the starter solenoid S-terminal and the positive battery terminal post.
6. Press the remote starter switch and record the voltage reading.
7. The voltage reading should be 0.5 volt or less. A reading higher than 0.5 volt indicates high resistance.
8. Repeat the test on the starter solenoid B-terminal.
9. If the readings are higher than 0.5 volt, remove the wiring from the starter solenoid.
10. Clean and inspect each wire connector and the starter solenoid terminal.
11. Install the wires onto the starter solenoid and retest.
12. If the reading at the starter solenoid M-terminal is still higher than 0.5 volt or the reading at the B-terminal is lower, carry out the Starter Solenoid Component Test. If no change is noted, install a new positive battery cable lead. Starter Solenoid
Starter Motor - Motor Ground Circuit Voltage Drop Test
NOTE: A slow cranking condition can also be caused by high resistance in the ground circuit.
1. Disconnect the wiring from the fuel pump electrical connector.
2. Connect the Digital Volt-Ohmmeter positive lead to the starter motor housing.
3. Connect the Digital Volt-Ohmmeter negative lead to the battery negative (-) terminal.
4. Connect a remote starter switch between the starter solenoid S-terminal and the positive battery terminal post.
5. Press the remote starter switch and record the voltage reading.
6. The voltage reading should be 0.2 volt or less. If the voltage reading is higher, remove and clean the negative cable connections at the battery, starter motor and the body.
7. Retest the system. If readings are still higher than 0.2 volt, test each individual negative cable.