ASE PREP: Automotive Starter this page also includes information for the BAR Diagnostic Repair Smog Course:
There will be questions on the Automotive-Starter system on the A6 ASE Test
The starter system includes the battery, ignition switch, safety switch, solenoid, starter motor. Some systems contain relays, fuses or fusible links.
Testing a starter usually requires the engine cranking over, just like any other electrical circuit, current has to be flowing to perform a voltage drop across the starter circuit components. A high voltage drop across a starter connection will cause starter cranking issues.
A neutral safety switch only allows a car owner to start their vehicle in park or neutral only, some switches are adjustable and if adjusted wrong the vehicle back up lights will stay on all of the time.
If the neutral starter switch has an open circuit, there will be no current flowing to the starter circuit. Remember in neutral or park the neutral safety switch should read continuity.
A neutral safety switch should read infinity in reverse or drive.
When one of the ohmmeter leads are placed on one of the switches terminal and the other lead is placed on the transmission housing, the meter should read infinity.
Almost all starting system tests are performed while the starter motor is cranking the engine. So you will need to bypass the ignition switch, to crank the starter over.
Make sure the transmission is out of gear during cranking
Do not crank the starter more than 30 seconds, to allow the starter to cool down between test.
Before removing a starter disconnect the negative battery cable
Some ASE Test questions may ask?
When the customer turns the key to start their vehicle and they hear a clash or grinding noise, what can cause this problem?
Now knowing how a starter works, here are a few items that will cause this problem.
Flywheel teeth chipped or broken
Bad Bendix Gear
Starter Shims missing or install incorrectly
Here are some of the components that can cause this problem.
Resistor/ Transponder in the ignition key
Neutral Safety Switch
Power-Train Control Module (PCM)
Current Draw Test:
This test determines how many amps it takes for the Starter to turn the engine.
The test is usually done with a VAT 40 or charging starter battery tester
Connect the remote starter
Connect the voltmeter in parallel to the battery
connect the inductive ammeter pickup around the positive cable
crank the engine for a few seconds no longer than 30 seconds, and take a reading of your voltage and amperage.
High current readings are caused by a short in the starter circuit or binding engine
Low current readings are the results from high resistance in the starter system circuit or defective battery
High battery voltage and low current readings indicate a bad battery
9.6 volts and an amp draw of 500 amps cranking could indicate a frozen engine or a starter drawing too much current
low volts and low amps cranking could indicate a battery or battery connection problem.
Cranking Voltage Test:
Use a remote starter button
Connect your voltmeter, either to the starter or relay follow the manufacturer procedure, crank the engine while watching the voltmeter.
9.6 volts are more and the amperage is high, the problem is in the motor, ignition timing is too far advance or the engine is binding
9.6 volts are more and amperage is low, the problem is high resistance
9.6 volts or less and the amperage is low. The battery should be tested.
Note: on some old GM alternators there was a ‘D” hole in the back of the alternator to test the regulator voltage. When you insert a pocket screwdriver in the hole the voltage should rise.
Watch this BAR / ASE Repair License Lecture:
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