Starting System: Testing and Inspection

DIAGNOSIS AND TESTING - STARTING SYSTEM

The performance of the starting system directly depends on the operation of the battery and charging systems. Always verify the battery and charging systems are operating according to specifications before diagnosing starting system faults.





INSPECTION

For complete starter wiring circuit diagrams, refer to Wiring Diagrams. Before removing any unit from starting system for repair or diagnosis, perform the following inspections:

WARNING: ON VEHICLES EQUIPPED WITH AIRBAGS, REFER TO PASSIVE RESTRAINT SYSTEMS, BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

- Battery - Visually inspect battery for indications of physical damage and loose or corroded cable connections. Determine state-of-charge and cranking capacity of battery. Charge or replace battery if required. Refer to Battery in, Battery.
- Ignition Switch - Visually inspect ignition switch for indications of physical damage and loose or corroded wire harness connections. Refer to Ignition Switch and Key Lock Cylinder.
- Park/Neutral Position Switch - Visually inspect park/neutral position switch for indications of physical damage and loose or corroded wire harness connections. Refer to Park/Neutral Position Switch in Transmission.
- Starter Relay - Visually inspect starter relay for indications of physical damage and loose or corroded wire harness connections.
- Starter Motor - Visually inspect starter motor for indications of physical damage and loose or corroded wire harness connections.
- Starter Solenoid - Visually inspect starter solenoid for indications of physical damage and loose or corroded wire harness connections.
- Wiring - Visually inspect wire harnesses for damage or corrosion. Repair or replace any wiring problems as required. Refer to Wiring Diagrams.

TESTING

COLD CRANKING TEST

For complete starter wiring circuit diagrams, refer to Wiring Diagrams. The battery must be fully-charged and load-tested before proceeding.

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




2. Fully engage parking brake.
3. Place gearshift selector lever in Park position.
4. Verify that all lamps and accessories are turned off.
5. To prevent engine from starting, remove Fuel Pump Relay.

WARNING: IF EQUIPPED WITH DIESEL ENGINE, ATTEMPT TO START ENGINE A FEW TIMES BEFORE PROCEEDING WITH FOLLOWING STEP.

6. Rotate and hold ignition switch in Start position. Note cranking voltage and current (amperage) draw readings shown on volt-ampere tester.
a. If voltage reads below 9.6 volts, refer to Starter Motor in Diagnosis and Testing. If starter motor is OK, refer to Engine Diagnosis in 9, Engine for further testing of engine. If starter motor is not OK, replace faulty starter motor.
b. If voltage reads above 9.6 volts and current (amperage) draw reads below specifications, refer to Feed Circuit Test.
c. If voltage reads 12.5 volts or greater and starter motor does not turn, refer to Control Circuit Testing.
d. If voltage reads 12.5 volts or greater and starter motor turns very slowly, refer to Feed Circuit Test.
7. Reinstall the fuel pump relay, and clear any fuel system DTCs that may have set as a result of the fuel pump relay being removed.

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

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, refer 8, Wiring 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 across the 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 engine from starting, remove Fuel Pump Relay. This relay is located in Power Distribution Center (PDC). Refer to label on PDC cover for relay location.
8. 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 voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post.




9. 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 voltmeter. If voltage is detected, correct poor contact between cable clamp and terminal post.




10. Connect voltmeter to measure between battery positive terminal post and starter solenoid battery terminal stud. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is above 0.2 volt, clean and tighten the battery cable connection at solenoid. Repeat test. If reading is still above 0.2 volt, replace the positive battery cable.




11. Connect voltmeter to measure between negative battery terminal post and a good clean ground on engine block. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is above 0.2 volt, clean and tighten negative battery cable attachment on engine block. Repeat test. If reading is still above 0.2 volt, replace faulty negative battery cable.




12. Connect positive lead of voltmeter to starter housing. Connect negative lead of voltmeter to negative battery terminal post. Rotate and hold ignition switch in Start position. Observe voltmeter. If reading is above 0.2 volt, correct poor starter to engine block ground contact.





If resistance tests do not identify high-amperage feed circuit problems, refer to Starter Motor in the Diagnosis and Testing.

CONTROL CIRCUIT TESTING

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

- Starter Relay - If the starter does not crank the engine when the EIS is in the start position, and there are DTCs related to the Starter/Engine Control Relay, refer to the appropriate diagnostics in Engine Electrical Diagnostics.
- Starter Solenoid - Refer to Starter Motor Diagnosis and Testing.
- Ignition Switch - If the starter does not crank the engine when the EIS is in the start position, and there are DTCs related to the EIS or Drive Authorization System (DAS), refer to the EIS diagnostic procedures in 8 Electrical.
- PCM or ECM - If the starter does not crank the engine when the EIS is in the start position, and there are DTCs related to the EIS, Drive Authorization System (DAS), or Starter/Engine Control Relay, refer to the appropriate diagnostics in Engine Electrical Diagnostics.
- Park/Neutral Position Switch - If equipped with automatic transmission and there are DTCs related to the Park/Neutral (P/N) switch, refer to the diagnostic procedures in Transmission/Transaxle.
- Wire harnesses and connections - Refer to the wiring diagrams in Electrical.