ECM/PCM Archives - Page 7 of 10 - UnderhoodService
Tech Tip: Audible Spark Knock, MIL On and DTC P0332 Set on GM Models

Some customers may comment on a mild to severe engine ping (commonly referred to as spark knock), usually worse during acceleration, and/or an illuminated MIL.

Tech Feature: Where Do You Start with Mercedes No-Start Diagnostics?

Hundreds of times a year, repair shops will get cars brought to them to repair a “No Start” fault. This article is going to discuss the process that it takes to make repairs when there are so many variables. Though this article will be focused on Mercedes-Benz, the steps can be used for any make or model.

Tech Tip: MIL On/DTC P2004 on Miata and MazdaSpeed Models

On some vehicles, after sitting overnight and being started, the MIL comes on and DTC P2004 sets into PCM memory. This occurs because vacuum (momentarily) does not flow into the Variable Tumble Control System (VTCS) shutter valve actuator.

Hyundai Tech Tip: No Spark, No Injector Pulse on 2002 Sonata 2.4 L Models

You may get a customer complaint that the vehicle died while in Drive, then wouldn’t start. There is no spark and no injector pulse, and no engine rpm on the scanner while cranking, and it’s setting a Crankshaft Position (CKP) sensor code P0335.

Engine Maintenance: OBD II Diagnostics, Misfire Codes, Fuel Trim Faults, Driveability and More

As automotive electronics diagnostics continues to evolve, so do the tools that are need to diagnose and repair today’s complex engine and electronics systems. This lineup will arm you will some diagnostic tips and give you some invaluable service advantages on Porsche, BMW, Hyundai and Mazda models.

Kia Tech Tip: DTC P0460 Update for Sephia Models

The original logic used for DTC P0460 (fuel level sensor circuit malfunction) in 2000 model year Sephias would illuminate the MIL and store a fault code for circuit-related problems (open or short), and for a fuel level input signal that failed to stay within the “plausibility” test limits stored in the ECM. “Plausibility” or “rationality” checks are frequently built into the ECM software to make sure that test results outside the normal range are detected as possible faults.

Tech Feature: Predicting Failures Through Mode $06

The PCM has several diagnostic modes. Depending on your scan tool and your use of it, you may get to see some or all of these modes. Also, depending on your scan tool, you may be accessing the various modes in the PCM without referring to them as “modes.”

What is Mode $06 and the other OBD II Modes?

OBD II modes are organized into nine categories, each of which is assigned a particular mode number preceded by a $ sign to symbolize the hexadecimal code it represents.

Tech Tip: Hyundai Check Engine Light Diagnostics

There are a couple of ways a Hyundai will find its way into your bay with a check engine light complaint. If a misfire is obvious, you may be tempted to get to work and start switching coils, checking wires or whatever, looking to diagnose the problem. But before you do, check the codes to see if more information is available.

Tech Tip: Volkswagen MIL On/DTC P1603 (18011) Stored

If DTC P1603 (18011) “Control unit faulty” is stored in the DTC memory on an affected vehicle, do not automatically replace ECM for this condition. First perform the following procedure.

Toyota Tech Feature: Diagnosing Today’s Complex Electronics Systems

Find out the latest innovations in scan tool technology, and what your scan tool should be doing for you.

ECMs Rarely Fail By Themselves

CARDONE offers technical advice on the causes of EMC failures.