Starting System Test

Starting System Test

The battery, starting, and charging systems operate in conjunction with one another, and must be tested as a complete system. For correct starting/charging system operation, all of the components involved in these three systems must perform within specifications.






Testing

Cold Cranking Test

• For complete starter wiring circuit diagrams. The battery must be fully-charged and load-tested before proceeding.

- Connect volt-ampere tester to battery terminals.. See instructions provided by manufacturer of volt-ampere tester being used.

- Fully engage parking brake.

- Place gearshift selector lever in Park position.

- Verify that all lamps and accessories are turned off.

- To prevent the engine from starting, remove either the ignition run fuse, or the fuel pump control fuse.


Attempt to start engine a few times before proceeding with following step.

• A cold engine will increase starter current (amperage) draw reading, and reduce battery voltage reading.

- Rotate and hold ignition switch in START position. Note the cranking voltage and current (amperage) draw readings shown on volt-ampere tester.

- If voltage is less than 9.6 volts. If starter motor is OK, refer to => [ Engine Mechanical System Test ] Engine Mechanical System Test for further testing of engine. If starter motor is not OK, replace faulty starter motor.

- If voltage reads more than 9.6 volts and current (amperage) draw reads less than specifications, refer to Feed Circuit Test in this section.

- If voltage reads 12.5 volts or greater and starter motor does not turn, refer to Control Circuit Testing in this section.

- If voltage reads 12.5 volts or greater and starter motor turns very slowly, refer to Feed Circuit Test in this section.

Feed Circuit Test

The starter feed circuit test (voltage drop method) will determine if there is excessive resistance in high-amperage feed circuit. For complete starter wiring circuit diagrams.

When performing these tests, it is important to remember that voltage drop is giving an indication of resistance between two points at which voltmeter probes are attached.

Example: When testing resistance of positive battery cable, touch voltmeter leads to positive battery cable clamp and cable connector at starter solenoid. If you probe positive battery terminal post and cable connector at starter solenoid, you are reading combined voltage drop in positive battery cable clamp-to-terminal post connection and positive battery cable.

The following operation will require a voltmeter accurate to 1/10 (0.10) volt. Before performing tests, be certain that following procedures are accomplished:

• Battery is fully-charged and load-tested.

• Fully engage parking brake.

• Place gearshift selector lever in Park position.

• Verify that all lamps and accessories are turned off.

• To prevent a gasoline engine from starting, remove the automatic shut down relay located in the integrated power module. Refer to label on IPM cover for relay location.

- Connect positive lead of voltmeter to negative battery cable terminal post. Connect negative lead of voltmeter to negative battery cable clamp. Rotate and hold ignition switch in START position. Observe the voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post.






• 1 - Voltmeter.

• 2 - Battery.

- Connect positive lead of voltmeter to positive battery terminal post. Connect negative lead of voltmeter to battery positive cable clamp. Rotate and hold ignition switch in START position. Observe the voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post.

Test Battery Positive Cable Resistance





• 1 - Battery.

• 2 - Voltmeter.

• 3 - Starter motor.

- Connect voltmeter to measure between battery positive terminal post and starter solenoid battery terminal stud. Refer to => [ Test Battery Positive Cable Resistance ]. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is more than 0.2 volt, clean and tighten battery cable connection at solenoid. Repeat test. If reading is still more than 0.2 volt, replace faulty positive battery cable.

Test Ground Circuit Resistance





• 1 - Voltmeter.

• 2 - Battery.

• 3 - Engine ground.

- Connect voltmeter to measure between negative battery terminal post and a good clean ground on engine block. Refer to => [ Test Ground Circuit Resistance ]. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is more than 0.2 volt, clean and tighten negative battery cable attachment on engine block. Repeat test. If reading is still more than 0.2 volt, replace faulty negative battery cable. Note: Certain diesel equipped models use dual batteries. If equipped with dual battery system, this procedure must be performed twice, once for each battery.

Test Starter Ground





• 1 - Starter motor.

• 2 - Battery.

• 3 - Voltmeter.

- Connect positive lead of voltmeter to starter housing. Connect negative lead of voltmeter to negative battery terminal post. Refer to => [ Test Starter Ground ]. Rotate and hold ignition switch in START position. Observe voltmeter. If reading is more than 0.2 volt, correct poor starter to engine block ground contact.

Control Circuit Testing

The starter control circuit components should be tested in the order in which they are listed, as follows:

• Starter relay.

• Starter solenoid.

• Ignition switch.

• Park/neutral position switch.

• Wiring harnesses and connections.