Computerized Powertrain Controls Diagnosis (Including OBD II)

Electronic engine control systems have been standard equipment on most cars and light trucks since the early 1980s. While these systems improve both driveability and fuel economy, their primary purpose is emission control. From a service standpoint, many of the early systems were difficult to diagnose due to their limited self-diagnostic capability. However, serviceability improved in 1988 with the implementation… Read More

Mode 06 Diagnosis

One of the keys to understanding Mode $06, or getting the most out of your scan tool, is to understand what the different modes are and how they are used. How many modes are there? There are 9 modes of scan tool operation. Many technicians have been using 4 or 5 modes for 20 years. Each of the 9 modes… Read More

Ford F-150 Misfire Mode $06 Diagnosis

This article will explain one of the most practical applications of Mode $06. The vehicle has a misfire but the MIL is not ON. It is a used car trade in with 120,332 miles and the repair history is unknown. The first obvious step is to scan it for codes. using a Generic scan tool to check the PCM and… Read More

Fuel And Air Induction Systems Diagnosis

Electronic Fuel Injection (EFI) was introduced to the automotive world in the late fifties, when Chrysler offered the ‘Electroinjector’ system as an option on its Hemi V8. Shortly after its debut, reliability problems forced Chrysler to recall the few sys­ tems that were sold. Ironically, re­ called vehicles were retrofitted with dual four-barrel carburetors. Three decades later the tide would… Read More

Diagnosing Computer Controlled HVAC Systems

Computer Controlled HVAC Pre OBD II Vehicles built prior to the advent of OBD II typically used electronic control modules only to operate their automatic temperature control systems. On these models, the control module was typically contained in the HVAC control head in the same unit housing the driver’s system control switches. Warning indicators may or may not be included on… Read More

A/C System Performance Testing Part 2

A/C Performance Testing A performance test can determine whether the A/C system is functioning properly and if it is not can indicate what is wrong so the system can be repaired.Different vehicle manufacturers specify different methods to conduct system performance checks, but as a guideline, the following procedure may be used.Connect a manifold gauge set as previously described. Hang the… Read More

A/C System Performance Testing Part 1

Automotive Refrigerants The refrigerant used in automotive air conditioning systems from their inception until the early 1990s was a chemical compound called dichlorodiflouoromethane, more commonly known as Freon or R12. R12 is a member of the chemical family known as chlorofluorocarbons(CFCs). Although R12 works extremely well as a heat transfer medium in an automotive air conditioning system, CFCs have been… Read More

Volkswagen Instrument Cluster Failure

Over the years of working on VW’s I have encountered enough instrument cluster failures that I would consider it a common problem. There are a few things you should be aware of before attempting to repair this unit. Don’t Buy Used VW Cluster I have tried this route already and have been burned multiple times. The bad part about it… Read More

Variable Valve Timing Systems

Why Use Variable Valve Timing? Increased Volumetric Efficiency Reduction of Pumping Losses Lower Parts Count More efficient Variable Valve Timing or VVT is common on most engines and is responsible for the elimination of many EGR valves as well as increased performance and fuel economy on many engines. Most systems are lube oil activated and use a control solenoid as… Read More

Honda Automatic Transmission Failure

Honda AT transmissions are common to have failure and I have rebuilt many of these over the years. Most transmissions have a pan you can remove and service the filter, which is a common service at around 30K to maybe 60K depending on the manufacturer and type of fluid ran in the transmission. Honda automatic transmissions have a closed case… Read More