Engine Control Modules (VIDEO)
Accurate diagnosis of any suspected ECM-related fault is important. This video is sponsored by The Group Training Academy.
ECM/PCM Communication Issues (VIDEO)
Before you swap out a module that won’t communicate, do a few simple inspections. Sponsored by The Group Training Academy.
Tech IQ: Getting Rid of Code P0315 (VIDEO)
The code might set again when the engine is cranked. This video is sponsored by Auto Value and Bumper to Bumper.
Oxygen Sensors: Pulse Measurement
Watching an oxygen sensor output on an oscilloscope is like watching a sporting event on television. You get to see the action, but can do nothing about it as it happens. Sometimes you miss the action and want an instant replay. It was a bad call. You saw the interference. If the referee didn’t see
Anti-lock Brake Case Study: 2002 Cadillac DeVille
• ABS light on • Traction control light on • Brake Warning light on • Codes C1248 – C1255 • No communication with electronic brake control module (EBCM) I always try to keep the diagnostic side as simple as possible: do the basics, get the codes, do the research and do it all as fast
The Cracked Plate Coincidence: Uncovering An Uncommon Flex Plate Issue Twice In One Week
It never ceases to amaze me when I see certain types of problems in rapid succession of one another and then not see them again for months or even years. This column is dedicated to one such occurrence. Within a week of each other, two different vehicles came into my shop with cracked flex plates. While I have seen flex plates crack throughout my career, it is not a common scenario.
Snap Test: MAF Sensor Diagnostics
You’d think a service light would be the first indicator of a mass air flow (MAF) sensor problem, but there are times a problem develops with the MAF and no service light comes on. Scott “Gonzo” Weaver explains how poor idle, loss of performance, sluggish performance and even stalling are all associated with a failing MAF sensor.
Diagnosing Variable Valve Timing
Fully variable valve timing can be achieved only by using computer-operated solenoids to precisely control the intake and exhaust valve opening and closing events. Although the various combinations of valve timing events are theoretically infinite on an electronically controlled system, their applications are limited due to issues of cost and, in some cases, reliability.
Cold Weather Diagnostics: Modules Go Down With The Temperature
The subject vehicles were 2002-2006 Ford trucks – the first was a 2002 Ford F-150 with a 5.4 liter, second was a 2006 Lincoln Navigator with a 4.6 liter and finally a 2004 Ford F-250 with a 5.4 liter engine. All of the customer complaints with these vehicles were the same: “The vehicle will not crank/start when cold.”
Audi Tech Tip: MIL On With P1545, P0121, P0123, P0221 Or P0222 Stored In ECM
The MIL is on, with a number of incident memory entries with regard to the throttle valve are stored in the ECM. In most cases, the entries are sporadic. This may be the result of contact resistance in the ECM wiring – throttle valve.
Tech Tip: Nissan Xterra Hesitates Upon Acceleration
The technician connected a scan tool and found code P0102 – Mass or Volume Air Flow “A” Circuit Low. He then performed an inspection of the mass airflow (MAF) sensor and related wiring harness, but found no obvious faults.
PCM Diagnostics Case Study: No-Code Misfire Diagnosis On A 1998 Toyota 4Runner
When doing mobile diagnostic work for other shops, contributing writer Gary Goms usually sees more than his share of random no-code engine performance complaints. In the following case study, the customer of a client shop complained about an intermittent rough idle on his well-maintained 1998 Toyota 4Runner, but only when it was driven in hot weather. The client shop couldn’t duplicate the complaint, no matter how long the engine ran. Of course, the lack of DTCs didn’t help the diagnostic process.