Component Tests and General Diagnostics

Before testing the starting system perform a visual inspection of the starting system components and connections.

Cold Cranking Test
Refer to Starting System for the location of complete starting system wiring diagrams. Before performing this test, be certain that the following procedures are accomplished:
- The battery is fully-charged and load tested. Refer to Battery Charging for battery charging procedures. Refer to Battery for battery diagnosis and testing procedures, including battery load test procedures.
- 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 the engine from starting, remove the Automatic ShutDown (ASD) relay The ASD relay is located in the Power Distribution Center (PDC), in the engine compartment. See the fuse and relay layout label affixed to the underside of the PDC cover for ASD relay identification and location.

Fig.1 Volts-Amps Tester Connections - Typical:

1. Connect a suitable volt-ampere tester to the battery terminals (Fig. 1). See the instructions provided by the manufacturer of the volt-ampere tester being used.
2. Rotate and hold the ignition switch in the Start position. Note the cranking voltage and current (amperage) draw readings shown on the volt-ampere tester.
a. If the voltage reads below 9.6 volts, refer to Starter Motor for starter motor diagnosis and testing procedures. If the starter motor tests OK, refer to Engine Diagnosis engine diagnosis and testing procedures. If the starter motor is not OK, replace faulty starter motor.
b. If the voltage reads above 9.6 volts and the current (amperage) draw reads below specifications, refer to the Feed Circuit Testing this section.
c. If the voltage reads 12.5 volts or greater and the starter motor does not turn, refer to the Control Circuit Test in this section.
d. If the voltage reads 12.5 volts or greater and the starter motor turns very slowly, refer to the Feed Circuit Test in this section.

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

Feed Circuit Test
The starter feed circuit test (voltage drop method) will determine if there is excessive resistance in the high-amperage starter feed circuit.

When performing the voltage drop test, it is important to remember that the voltage drop is giving an indication of the resistance between the two points at which the voltmeter probes are attached. EXAMPLE:When testing the resistance of the battery positive cable, touch the voltmeter leads to the battery positive cable terminal clamp and to the battery positive cable eyelet terminal at the starter solenoid B(+) terminal stud. If you probe the battery positive terminal post and the battery positive cable eyelet terminal at the starter solenoid B(+) terminal stud, you are reading the combined voltage drop in the battery positive cable terminal clamp-to-terminal post connection and the battery positive cable.

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. Refer to Battery Charging for battery charging procedures. Refer to Battery for battery diagnosis and testing procedures, including battery load test procedures.
- 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 the engine from starting, remove the Automatic ShutDown (ASD) relay The ASD relay is located in the Power Distribution Center (PDC), in the engine compartment. See the fuse and relay layout label affixed to the underside of the PDC cover for ASD relay identification and location.

Fig.2 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 (Fig. 2). Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If voltage is detected, correct the poor contact between the battery negative cable terminal clamp and the battery negative terminal post.

Fig.3 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 (Fig. 3). 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.

Fig.4 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 (Fig. 4). 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.

Fig.5 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 (Fig. 5). 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.

Fig.6 Test Starter Ground - Typical:

5. Connect the positive lead of the voltmeter to the starter housing. Connect the negative lead of the voltmeter to the battery negative terminal post (Fig. 6). Rotate and hold the ignition switch in the Start position. Observe the voltmeter. If the reading is above 0.2 volt, correct the poor starter to engine block ground contact.

If the resistance tests detect no feed circuit problems, refer to Starter Motor.

Control Circuit Test
The starter control circuit components should be tested in the order in which they are listed, as follows:
Starter Relay
- Refer to Starter Relay.

Starter Solenoid
- Refer to Starter Motor.

Ignition Switch
- Refer to Ignition Switch and Key Lock Cylinder for ignition switch diagnosis and testing procedures.

Clutch Pedal Position Switch
- If the vehicle is equipped with a manual transmission, refer to Clutch Pedal Position Switch for clutch pedal position switch diagnosis and testing procedures.

Park/Neutral Position Switch
- If the vehicle is equipped with an automatic transmission, refer to Park/Neutral Position Switch for park/neutral position switch diagnosis and testing procedures.