Diagnostics Archives - UnderhoodService
Auxiliary Water Pump Diagnostics

A car or truck comes into your shop with a complaint of poor heater performance- the issue may be the auxiliary water pump.

Hybrid Vehicle Fluid Maintenance

There are opportunities your shop can’t pass up just because the car or SUV has a hybrid badge on the back.

Ignition Coil Output

To see inductance inside the primary windings, use an amp probe placed around the positive wire for the ignition coil.

Diagnosing Intercooler Boost Trouble Code P0299

The criteria for setting the code is very basic.

Why Alternators Are Subject To Ripple Voltage

The alternator produces an AC current that must be converted into DC current by way of a rectifier.

Diagnosing Misfires

What if there are no codes and a misfire is intermittent? This is where it gets complicated.

Using a Scope

Ignition coil and plug diagnostics.

Scope-diagnostics
Repairing Wiring Harnesses

A guide to probing and poking.

Lifter Deactivation

The area of contact between the lifters and cam lobes is the highest loaded surface inside an engine.

Diagnostic Procedures For Stop/Start Systems

Stop/start technology is more than just a switch wired to the brake pedal and starter.

Alternator Testing For No Charge Conditions

Many alternator problems turn out to be nothing more than a bad connection at the alternator or a bad wiring harness.

Diesel Air Filter Replacement

Here are some diesel air filter replacement tips in order to keep these vehicles running as intended.