1. Pressure Transducers
A scope can be used to diagnosis mechanical systems if you have the right scope accessories. A pressure transducer turns pressure changes in air and fluids into signals that can be displayed on a scope. With a pressure transducer connected to the dipstick tube, you can perform a leak-down check without pulling a single spark plug. They can also be used on cooling, transmission and exhaust systems. Kits will vary in price depending on the pressure range of the transducer and the adapters included in the set.

2. Breakout Boxes
One of the best investments you can make is the purchase of breakout boxes. A breakout box can allow you to leave a scan tool connected while still having access the pins of the OBD II connector. This can be very helpful when diagnosing serial data bus problems.

3. Connector Adapters
On some circuits, sticking a pin into the insulation can lead to corrosion problems like in the case of wheel speed sensor circuits. Connector adapters can allow you to make your measurements without damaging the insulation or pins in the connector.

4. Current Clamps
Current clamps can measure the draw of a module to the amount of current needed for a starter. If you need to measure the amount of current in a circuit; you need a current clamp. Be sure to select the right range and features for your diagnostic needs.

5. Test Leads
You can skimp on the scope, but never skimp on the test leads. Better-quality leads have better shielding to prevent random signals from leaking into the wires. Higher-quality leads use higher-quality materials that are temperature resistant and are more ­flexible. They don’t tangle easily and you won’t fight them.

6. Gators and Probes
Your test leads are only as good as what is connected at the other end. High-quality alligator clips can help you by establishing a stable ground to test circuits. Back probe pins can be found in many sizes. These pins can be used to pierce wires and the insulation in connectors to reach the terminal. When buying pin probes, the more money you spend, the smaller the probe.

7. Secondary Ignition Signal Probes/Paddles
These inductive sensors can be placed on ignition coils to capture the secondary ignition waveform. They do not require any back-probing or removal of the coil. Some of the probes and paddles can be used to ­monitor fuel injector cycle times.

8. Case
Any amount of money spent on a protective case for your scope will be recouped when you try to sell your scope. A quality case will protect your scope from chemicals and the occasional drop.

9. Time & Training
The best accessories you can purchase for your scope are time and training. Great scope technicians are not born, they are made. During shop downtime, pull out your scope and start playing with the menus and measure a few vehicles to build a waveform library. Take time with the manual and use any online support.