Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Testing
- Ignition/Vehicle - Off
- Verify the following tool contains the latest software: Oscilloscope
- If not the latest software
Download - Latest software
- Go to next step: If the latest software
- If not the latest software
- Apply - Parking Brake
- Install - CH-51450-A Oscilloscope Diagnostic Kit & CH-51450-LEAD-A Oscilloscope Basic Lead Kit
- Channel A Lead: Blue @ Oscilloscope
- Channel A Lead: Blue @ B+ & Ground
- Select: Channel Options - A
- Select: Coupling - DC
- Select: Connect Detect
Verify the following information is correctly displayed: Connected Channels = Green
- If the information is not correctly displayed
Repair the poor connection & Repeat this step
- Go to next step: If the information is correctly displayed
- If the information is not correctly displayed
- Setup - CH-51450-A Oscilloscope Diagnostic Kit
- Select: Guided Tests
- Select: Charging and Starting
- Select: Starting
- Select: Cranking Voltage
- Select: Running - Start Capturing
- Perform the following action:
- Fully Applied - Accelerator Pedal - Wide Open Throttle
- {Automatic Transmission} Apply & Hold - Brake Pedal
{Manual Transmission} Apply & Hold - Clutch Pedal
- Engine - Cranking - For 5 - 10 s
- Select: Stopped - Stop Capturing
Verify the following information is correctly displayed: The waveform valleys are all even. Refer to: Oscilloscope Waveform Library
NOTE:Make sure the component is not obstructed: Accelerator Pedal
- If the information is not correctly displayed
Verify the condition does not exist with the component and repair as necessary:
- Camshaft Lobe(s) - Visible Damage/Worn
- Exhaust Valve or Intake Valve - Stuck Open/Visible Damage
- Exhaust Valve Seat or Intake Valve Seat - Visible Damage
- Piston - Cracked/Visible Damage
- Piston Ring - Seized/Visible Damage/Worn
- Valve Lifter - Visible Damage/Worn
- Valve Rocker Arm - Visible Damage/Worn
- Valve Spring - Visible Damage/Worn
NOTE:The following are examples of what could cause compression issues. Inspect all mechanical components for the applicable cylinder. The list is not all encompassing - Refer to: Symptoms - Engine Mechanical
- Go to next step: If the information is correctly displayed
- All OK.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.