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Checking into Mode $06

Mode 06 is the actual system test data that OBD II looks at when it decides to set a pending code or a current fault code. If the test data is within the limits established by the vehicle manufacturer, the item gets a PASS and no codes are set. But if a value is out of range, OBD II flags it with a FAIL and keeps an eye on the component until the system monitor has run at least twice. Then, if the problem is still there, a DTC is set and the MIL light comes on.

Selling Service for Low-Maintenance Ignition Systems

ition system maintenance as long as it feels like it’s “running good.” In reality, spark plugs eventually develop high electrical resistance because the electrodes wear away. When this happens, the secondary ignition voltage will increase until the ignition coil, ignition cable, spark plug boot or spark plug develops a high-voltage leak. When a high-voltage leak

When it’s Time for a Rebuilt Engine Installation

I noticed the Toyota 4WD truck as soon as I turned into the parking lot on Monday morning. I knew the owner because we’d been servicing his vehicles for a number of years, and I was always impressed by how clean and straight the truck was for its age. It was parked kind of crooked,

Selling Oxygen Sensors

As modern OBD II technology marches on, it’s clear that the zirconia-based oxygen sensor now is being sold more as a basic repair part than as a preventive maintenance part, and it changes the way we diagnose and sell oxygen sensors. To illustrate the difference, let’s remember that an oxygen sensor replacement used to be

A Tutorial in Hyundai Driveability

Diagnosing a driveability problem starts with the customer interview. When you are able to obtain the proper details about the vehicle’s symptoms, you will be able to diagnose the source of the problem more efficiently. Clues provided by the customer, such as “vehicle starts but runs rough until warm; worse when wet,” is invaluable information

How Sensors Provide ‘Good Input’ for Diagnostics

One of the systems that Subaru has perfected through improved reliability over the years has been its distributorless ignition system (DIS) for all of its models. Because of the horizontally opposed design of its engines, the ignition system can be centrally mounted and made simple. In this article, we will touch on some common diagnostic

Subaru Steering & Axle Service

Here in the Northwestern part of the country, Subaru has become one of the top nameplates. The versatility of the all-wheel-drive system makes them the ideal ski team hauler or beachcomber vehicle. The compact station wagon design is the most popular model, due to its ability to haul people, and their equipment, in comfort and

GM Timing Belt & Chain Service

Some overhead cam engines in General Motors vehicles use timing belts to drive the cam (the 2.0L for example), some use chains (2.3L Quad Four, Cadillac’s Northstar dual overhead cam 4.6L V8, the Aurora Northstar 4.0L V8 and Chevy’s Vortec 4200 inline six), and some use a combination of both (Chevrolet’s 3.4L V6). The rest

The Fuel Injector Market and System Configurations

Looking back into automotive history, it’s hard to believe that carburetors were still being installed on import vehicles as late as 1989! But carburetors require all sorts of external vacuum and electronic gimmickry to control the cold-starting, fast idle, hot idle and low-speed cruise functions. Electronic fuel injection has since replaced carburetors in all import

Carburetor Repairs & Recalibrations

As a follow-up to “Dusting Off Fuel System Fossils” in April’s edition of Underhood Service, I will share many driveability concerns and emissions failures that I’ve repaired by rebuilding, and sometimes modifying, certain carb circuits. But before diving into a carburetor rebuild or recalibration, be certain that you understand the system you’re working on, including