A Closer Look: Ignition Coils
OE coils are known for their high failure rates. Engine misfires, rough idle, a decrease in power under acceleration, poor fuel economy, and a check engine light are all signs of an ignition coil that has failed. Read along for more technical information on how to diagnose a failed coil, and why the original equipment
ECM and PCM Calibration Numbers
Finding out if the vehicle has the latest version or calibration on a module is a required step.
Nissan PCM Computer-Control Issues
The American writer Irene Peter said it best: “Just because everything is different doesn’t mean anything has changed.” By 2018, I thought everything had changed since the days of On-Board Diagnostics I (OBD I). Since OBD I evolved into OBD II in 1996, many things did indeed appear to be different. But, once in a great while, engineers design a vehicle that is slightly ahead of its time. For me, it was a 1995 Nissan pickup equipped with the 3.0-liter V6 engine and manual transmission. Surely being an oddity, it would start and run with the distributor disconnected.
The No-Code Conundrum: The Art Of Diagnosing What The PCM Can’t See
Doing mobile diagnostics, I obviously get more than my share of no-code driveability problems. Case in point, I was asked by a client shop to “take a quick look” at a stalling complaint on a 2003 Ford Explorer with a cable-operated throttle.
The Art of Diagnosing What the PCM Can’t See
The difficulties of diagnosing no-code drivability problems are best summed up by one of Yogi Berra’s famous quotes, “When you come to a fork in the road, take it.”
Throttle-By-Wire Codes: P1512 On 2002 GMC Envoy
The PCM continuously monitors the commanded and actual throttle positions. The commanded throttle position is compared to the actual throttle position based on accelerator pedal position and possibly other limiting factors, and both values should be within a calibrated range of the other.
Diagnostic Dilemmas: Pinball Effect: Sorting Through Multiple Codes and Problems
“My dash lights up like a pinball machine, the engine loses power for a few seconds, and then seems to run OK.” Although I’d actually been chasing this Diagnostic Dilemma for the better part of a year, this four-wheel drive 2001 Blazer equipped with the 4.3L Vortec engine and manual transmission otherwise appeared to be
Diagnostic Dilemma: The Case of the Missing Code
When doing mobile diagnostic work, no-code stalling complaints are a major part of your agenda. In most cases, the client shop is simply too busy to duplicate the failure or, in some cases, a long test drive will yield nothing in the way of useful scan tool data. With many no-code stalls, all you’re going
‘5 Checks’ Recommendation Simplifies Emissions System Diagnosis, Repair
Tenneco’s Walker Emissions Control brand is helping automotive service providers simplify emissions control diagnosis and repair through a variety of new educational tools, including a recommended set of five checks to perform before installing a replacement catalytic converter. These diagnostic checks are covered in a free technical video available through the “TennecoInc” channel at YouTube.com.
Random No-code Failures: Jeep Cherokee, Ford Crown Victoria
Random no-code failures can be the most frustrating problems to diagnose because the condition usually cant be duplicated in the shop and the “fix” often cannot be verified by test-driving. In this instance, I use the word “random” to describe a condition that might occur only once in two weeks. Sometimes I’ll find something suspicious
Case Study: 1996 GMC 1500 with no temperature control
• No A/C, no vent control, no temperature control • A/C and recirculation buttons will not light up • All new components, including compressor and control head Cars with a little age on them can be temperamental when diagnosing what might seem at first to be an easy problem. This 1996 GMC had already gone
The Case of the Missing Starter
I was called last fall by a client who owns a heavy-duty diesel shop to diagnose a no-cranking condition on his father-in-law’s 2006 Chevrolet Tahoe. Because his work is mainly with heavy-duty trucks, my client knew he was lacking both in tooling and technical background when he didn’t hear the familiar click of a starter
