BMW Climate Control Diagnostics: Resolving Any Cooling System Problems First Speeds Repairs
First Speeds Repairs There was a time when the heating and ventilation system on most cars was simple. A three-position switch, a couple of levers and maybe some separate vents that would allow outside air to enter the passenger compartment. Times have changed and today’s car buying public wants to dial in a desired temperature
Diagnostic Solutions: Rediscovering Oxygen Sensors
If you’re like me, you more often than not find a correct diagnostic direction by going back to what trainers are fond of calling “The Basics.” I capitalized “The Basics” because they are the foundation upon which all of us should be building our diagnostic strategies. The Basics were brought to mind recently when I
COP Connection: Investigating Common Coil-on Plug Misfires
For a number of reasons, the trend of modern engine management technology is leaning toward using coil-on-plug (COP) ignition systems. One reason is that COP ignitions are very compact and are very adaptable to individual cylinder tuning. With the exception of a few designs that incorporate a driver or “module” into the COP assembly itself,
Diagnostic Dilemmas: Down to the Wire
Five years ago, I began seeing a very small number of General Motors products come through the door with a variety of trouble codes indicating a “circuit failure” in the intake air temperature (IAT) sensors, mass air flow (MAF) sensors, throttle position (TP) sensors and idle air control (IAC) systems. In all cases, these failures
Electrical System Tools and Equipment
Neutrons, Electrons, Klingons? As today’s cars and systems have gotten more and more complicated, so have the tools and equipment needed to work on those cars. The professional technician is expected to be able to understand electrical theory, electronics, physics, as well as understand and interpret readings from complex electrical test equipment.
Tech Tip: OBD II Engine Diagnostics
Anybody can plug a scan tool into a vehicle and read codes. But do they know what the codes mean, how to diagnose the fault or, most importantly, how to fix the vehicle? The problem with reading OBD II codes is that the code tells you only that a fault has occurred. It does not tell you why the fault occurred, what might be causing the problem, or what needs to be repaired or replaced ….
Getting a Grip on Traction Control
The basic principle of traction control is rather simple. A tire is breaking free and starting to spin so we’re going to place a drag on that wheel so that two things can happen. One is we want that tire to have a chance to regain its grip on the road surface. And two, we
Belt and Hose Inspections
Don’t Lose Potential Profits by Missing Replacement Opportunities
Tech Tip: Finding the Failure Pattern
All diagnostic techs are eventually confronted with a random, no-code failure that occurs only under a very narrow range of circumstances. All too often, solving a random, no-code malfunction is a long-shot proposition for any diagnostic tech because a particular combination of events is required to initiate that particular malfunction. Sure, every once in a while a technician can get lucky with a chance roll of the diagnostic dice, but that’s about it when it comes to ….
Tech Tip: Diagnosing an Engine that Won’t Start
For any engine to start, three things are necessary: fuel, compression and spark. If any of these components is lacking, the engine won’t start. The fuel system must be generating normal fuel pressure, and the air/fuel ratio must be correct for the ambient temperature and engine temperature. If the air/fuel mixture is too lean, it won’t ignite and the engine won’t start. If the air/fuel mixture is too rich, it can flood the engine and also prevent it from starting ….
Tech Tip: Diagnosing Malfunctioning Jeep Instrument Cluster
The same two-wire CCD BUS that Chrysler has been using for years on its cars is now being used on Jeeps and trucks, giving today’s Jeep Wrangler a new level of sophistication. If the instrument cluster doesn’t work, first determine which gauges don’t operate or if the whole cluster is down. I like to start testing with the printed circuit board self test ….
Tech Tip: Engine Knocking Noise Just Above Idle May Be Normal
Engine "knock" may be heard on an applied vehicle just above engine idle speed (800-1,100 rpm) with the engine under a slight load. The noise cannot be detected over 1,100 rpm. The cause may be a normal pulsating noise coming from the EVAP purge solenoid valve and piping (in the engine compartment) transferring into the passenger cabin. However, use the following procedure to reduce the noise ….