ECM/PCM Archives - Page 8 of 10 - UnderhoodService
Tech Feature: Mass Airflow Sensors Are Critical In Today’s Engine Management Systems

In addition to providing an exact measurement of airflow into the engine, airflow sensor inputs can be used to provide a load-sensing input to the powertrain control module (PCM) to help control the shift points and shift quality of an automatic transmission.

Alignment Trends: What is the Future of the Alignment Bay?

In the past two years, we have seen more vehicles on the market with stability management and adaptive cruise control. If a vehicle with one of these systems comes into your shop for alignment, be aware that any changes in the steering position sensor’s “zero” position may have drastic consequences for the safety of the vehicle. If the data from a steering position sensor is off after an alignment adjustment, the car could think it is in a turn and try to perform a correction.

Volkswagen: DTCs 00545/00638 Stored

If DTCs 00545/00638 are stored on a 2003 Passat Sedan 4Motion, the problem may be caused by: • Incorrect Engine Control Module (ECM) coding (codeable ECM only); • Wiring harness and/or connections between the Transmission Control Module (TCM) and ECM; • Malfunctioning ECM; • Intermittent continuity in the engine harness. • Poor engine compartment ground

Tech Feature: Mazda Driveability Diagnostics and Check Engine Light Complaints

From a torn air intake hose to ignition system concerns, Bob Dowie tackles driveability issues as well as some of the more common ailments that will bring Mazda vehicles into your bays with a check engine lamp complaint.

Mercedes ‘CAN’ Diagnostics — Uncovering Faults Speeds The Repair Process

Dealing with frustrating error messages on your scanner? Import Specialist Contributor Larry Bailly covers some of the more common faults when dealing with Mercedes CAN wiring, what it takes to plan and achieve diagnostic success, and the places to look for the cause of faults.

Tech Feature: ‘Exploring’ Ford 4.0/4.6L SUV Engines

Since 2002, the Ford Explorer and Mecury Mountaineer have undergone a number of noticeable engine changes. Glen Beanard reveals which engines offer newer features and offers tips on how to handle service and repair challenges with these vehicles.

Reprogramming ABS Controllers

Reflashing undercar controllers is possible at your shop!

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,

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

Finding the Failure Pattern

but that’s about it when it comes to diagnosing random, no-code malfunctions. Lucky or not, the chances of locating the cause of a random, no-code malfunction can be increased by determining the sequence of events needed to trigger the malfunction. Determining this sequence of events is what I call, “Finding the Failure Pattern.” From the

Diagnosing a Car’s Intermittent Stalling Issues

Causes, Solutions, and Diagnostic Steps to Troubleshoot Engine Stalling Issues.

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Downloading Repairs

Have you looked at technical service bulletins lately? Especially ones for vehicles built since 2004? The fixes have changed drastically. I remember a time, not too long ago when the fix in a typical TSB was to install an updated part. From where I stand now in a Ford dealership, it seems like the hardware