Voltage Drop Test
VOLTAGE DROP TESTWARNING: MODELS EQUIPPED WITH THE DIESEL ENGINE OPTION ALSO HAVE AN AUTOMATIC SHUTDOWN (ASD) RELAY LOCATED IN THE POWER DISTRIBUTION CENTER (PDC), IN THE ENGINE COMPARTMENT. HOWEVER, REMOVAL OF THE ASD RELAY MAY NOT PREVENT THE DIESEL ENGINE FROM STARTING. BE CERTAIN TO ALSO DISCONNECT THE FUEL SHUTDOWN SOLENOID WIRE HARNESS CONNECTOR ON MODELS WITH A DIESEL ENGINE. FAILURE TO DO SO MAY RESULT IN PERSONAL INJURY.
The following operation will require a voltmeter accurate to 1/10 (0.10) volt. Before performing this test, be certain that the following procedures are accomplished:
- The battery is fully-charged and load tested
- Fully engage the parking brake
If the vehicle is equipped with an automatic transmission, place the gearshift selector lever in the Park position. If the vehicle is equipped with a manual transmission, place the gearshift selector lever in the Neutral position and block the clutch pedal in the fully depressed position.
Verify that all lamps and accessories are turned OFF.
To prevent a gasoline engine from starting, remove the Automatic ShutDown (ASD) relay. The ASD relay is located in the Integrated Power Module (IPM), in the engine compartment. See the fuse and relay layout label affixed to the underside of the IPM cover for ASD relay identification and location.
Fuel Shutdown Solenoid Connector - Diesel Engine:
To prevent a diesel engine from starting, disconnect the fuel shutdown solenoid wire harness connector.
Test Battery Negative Connection Resistance - Typical:
1. Connect the positive lead of the voltmeter to the battery negative terminal post. Connect the negative lead of the voltmeter to the battery negative cable terminal clamp. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If voltage is detected, correct the poor connection between the battery negative cable terminal clamp and the battery negative terminal post.
NOTE: If the vehicle is equipped with a dual battery system, Step I must be performed twice, once for each battery.
Test Battery Positive Connection Resistance - Typical:
2. Connect the positive lead of the voltmeter to the battery positive terminal post. Connect the negative lead of the voltmeter to the battery positive cable terminal clamp. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If voltage is detected, correct the poor connection between the battery positive cable terminal clamp and the battery positive terminal post.
NOTE: If the vehicle is equipped with a dual battery system, Step 2 must be performed twice, once for each battery.
Test Battery Positive Cable Resistance - Typical:
3. Connect the voltmeter to measure between the battery positive cable terminal clamp and the starter solenoid B(+) terminal stud. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If the reading is above 0.2 volt, clean and tighten the battery positive cable eyelet terminal connection at the starter solenoid B(+) terminal stud. Repeat the test. If the reading is still above 0.2 volt, replace the faulty battery positive cable.
NOTE: If the vehicle is equipped with a dual battery system, Step 3 must be performed on the driver side battery only.
Test Ground Circuit Resistance - Typical:
4. Connect the voltmeter to measure between the battery negative cable terminal clamp and a good clean ground on the engine block. Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If the reading is above 0.2 volt, clean and tighten the battery negative cable eyelet terminal connection to the engine block. Repeat the test. If the reading is still above 0.2 volt, replace the faulty battery negative cable.
NOTE: If the vehicle is equipped with a dual battery system, Step 4 must be performed twice, once for each battery.