Trace 12V Circuit Faults with a Display-Equipped Test Pen
The CMTOOL P50 is a probe-style circuit tester for 12V vehicle systems. It shows live voltage, identifies polarity and helps check fuses, batteries, sensors and wiring faults.
- 12V Systems
- Digital Voltage Readout
- 3 Working Modes
- 5W Replaceable Bulb
- Hall Sensor Testing
Key Features
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Live Voltage and Polarity
A digital display on the pen body shows voltage in real time and indicates whether the probed point is positive or negative.
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Three Working Modes
Press the button on the body to cycle between display and bulb together, display only, or bulb only.
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Fuse, Battery and Short-Circuit Checks
Check fuses, battery performance and short-circuit faults, and help tell solid power from virtual power, series connections and poor grounds.
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Sensor and Network Circuits
Test Hall sensor performance and LAN circuits, and probe idle, ignition, fuel injection, vehicle speed sensor and ABS circuits.
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Signal Frequency Estimate
On pulsing signals such as fuel injector, spark plug and crankshaft sensor circuits, display bars give a rough indication of the signal’s frequency range.
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Built-In Light
The replaceable bulb at the end of the pen doubles as a torch for dark engine bays.
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Probe and Clip Lead
A pointed steel probe tip on the pen, plus a lead fitted with an alligator clip and a second probe.
Good to Know
Caution
- Designed for 12V vehicle electrical systems. Do not use it on household mains power.
- Avoid probing airbag/SRS circuits and sensitive module signal lines with a powered tester; check the vehicle’s service information first.
Care
- Attach the clip to a known-good ground or battery terminal before probing.
- Replace the bulb with one of the same rating and keep the probe tip clean.
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