ABYC Diesel Practice Exam

What might lower than normal amp clamp readings indicate when testing a starter motor circuit?

1. A defective starter

2. Loose or corroded cabling

3. Low battery voltage

4. A malfunctioning alternator

The correct answer is: Loose or corroded cabling

Lower than normal amp clamp readings when testing a starter motor circuit can indicate issues with the cabling, such as loose connections or corrosion. The starter motor requires a specific amount of current to operate effectively, and if the cables leading to the starter are compromised, it will limit the current flow. Loose connections can create resistance in the circuit, and corrosion can also impede electrical conductivity, both of which can result in insufficient current being delivered to the starter motor. While a defective starter or low battery voltage can also contribute to suboptimal performance, these issues would not specifically correlate with lower amp clamp readings as directly as issues relating to cabling would. The amperage measurement is particularly sensitive to the quality of connections in the circuit, making the condition of the cabling a critical factor in accurately diagnosing starter motor performance.