Automotive Service Excellence (ASE) A6 Electrical/Electronic SystemsStarting System Diagnosis and RepairMedium
A technician is diagnosing a vehicle that experiences a 'click, no-crank' condition. The battery is fully charged and passes a load test. When the key is turned to 'START', a single loud click is heard from the starter solenoid, but the engine does not crank. What is the most probable cause?
- AAn open in the starter motor's field windings
- BA faulty neutral safety switch
- CLow voltage at the starter solenoid S-terminal
- DA corroded battery terminal connection
Show answer & explanationAnswer & explanation
Correct answer: A. An open in the starter motor's field windings
A 'click, no-crank' with a good battery and a single loud click from the solenoid indicates the solenoid is engaging and closing the main contacts, but the starter motor itself is not turning. An open in the field windings would prevent the motor from spinning, even with power applied.
Why the other options are wrong
- B. A faulty neutral safety switch would result in a 'no-crank, no-click' condition.
- C. Low voltage at the S-terminal would likely result in a 'no-click' or a weak, multiple-click sound.
- D. A corroded battery terminal would cause a significant voltage drop, leading to either a 'no-crank, no-click' or a 'slow crank' condition, or multiple rapid clicks if the solenoid chatters due to insufficient current.
Click, No-Crank Diagnosis
A diagnostic scenario where the starter solenoid audibly clicks once, but the engine does not turn over, typically indicating a problem with the starter motor itself or severe resistance in the main power circuit.
- Solenoid is engaging, meaning control circuit is likely good.
- Battery and main cables should be checked for high resistance.
- Common causes include internal starter motor failure (open windings, seized bearings), or a mechanically locked engine.
Memory trick: Click means power, no crank means the motor's a blank.