Tech Tip: Honda Has MIL On with DTC P1457
The EVAP bypass solenoid valve can fail due to corrosion, caused by water getting inside. If the water contains road salt, the solenoid windings could corrode, causing the valve to fail. In a few rare instances, the corrosion could be severe enough to cause an internal short in the solenoid valve, which could damage the ECM/PCM. If this happens, both the bypass solenoid valve and the ECM/PCM would need to be replaced.
Diagnostic Dilemmas: 8 Simple Rules …
Many of the “Diagnostic Dilemmas” Gary Goms is called upon to solve aren’t really all that complicated – but were caused by basic oversights and incorrect assumptions on the part of the technician. This situation has largely been caused by a lack of training and, in some cases, poor training.
Diagnostic Solutions: The Relationship Between PCMs, Sensors and Actuators
Not that I recommend installing used PCMs, but I occasionally need a rebuildable core to replace a missing or badly damaged powertrain control module (PCM). But lately, I’ve noticed that it’s becoming increasingly difficult to find a used PCM for an older import at a local auto salvage yard. While it’s sheer speculation on my part, this apparent shortage of PCM cores might be caused by too many poorly trained technicians replacing PCMs to solve sensor-based problems. In most of these cases, the problem remains unsolved even as the original and fully functional PCM is casually tossed into the trash when the tech moves on to another job.
Tech Tip: Hyundai Has Check Engine Light On with Fuel System Lean Code
The check engine light is on with a post catalyst fuel system lean code P2096, an oxygen (O2) sensor stuck lean B1/S2 code P2270, and an O2 sensor no activity B1/S2 code P0140.
Tech Tip: Volkswagen MIL is On, with DTCs P0087/P1093 or P2293
The MIL is on, with DTC P0087 (Fuel Rail/System Pressure Too Low), P1093 (Fuel Trim 2, Bank 1 Malfunction) or P2293 (Fuel Pressure Regulator 2 Performance) stored in the ECM’s fault memory. This could be caused by excessive wear of the intake camshaft lobe that drives the high-pressure fuel pump. The wear limits maximum pump piston lift, causing fuel rail pressure fluctuations. The wear on the camshaft lobe can also lead to wear on the base of the high-pressure fuel pump cam follower.
Tech Tip: Nissan MIL On, DTC P0603 – ECM Power Supply
If you have a vehicle with the MIL on that has a DTC P0603 stored in the ECM, perform the diagnostic steps in this bulletin first.
Tech Tip: Tacoma’s MIL Is On with DTC P0705 Set
Some 2005-’09 model year Toyota Tacoma vehicles may exhibit an MIL On condition with DTC P0705 (Transmission Range Sensor Circuit Malfunction [PRNDL Input]) stored.
Tech Tip: Ford Traction Control Light On/No DTC, or DTC P1889
Some 2005-’07 Five Hundred, Freestyle and Montego vehicles equipped with all wheel drive (AWD) may exhibit the traction control warning lamp on.
Diagnostic Dilemmas: The Diagnostic Tail Gunner – Surviving in the Age of Information
One of the first survival skills my professor taught is called “preparatory set,” which is simply the act of preparing to do something. Each of us engages in preparatory set when we open our toolboxes each morning. The very act of opening our toolbox signals to our mind that we’re ready to go to work and deal with the day’s issues.
Tech Tip: Kia Has Intermittent MIL On with No Fault Code Stored
In affected vehicles, an intermittent short to ground in a circuit only intended for testing purposes may cause the MIL to illuminate and a DTC P1330 (Spark Timing Adjust) to be stored. As soon as the fault disappears, the MIL may turn off and the fault code can also be immediately erased by the engine management system, making it hard to diagnose the concern.
Pulling Codes: The Story of U1016
This Pulling Codes article will center on issues involving the powertrain control module (PCM) talking to your scan tool. In many states, this is the controller our scan tool needs to talk to in order to determine if the correct number of monitors has run and passed. It’s interesting to note that there appears to be two modes of failure in terms of communication.
Diagnostic Dilemmas: When Over-Voltages Electrocute PCMs
During the past nine months, I’ve had three instances of powertrain control module (PCM) failures on Jeep Wrangler vehicles that were evidently caused by an over-voltage condition. The first case involved an owner who requested that a local shop replace the fuel pump because his 1998 Wrangler was slow-starting in the morning. The shop found the pump pressure was marginal and replaced the pump. Because the Jeep still had the problem, the owner complained about the fuel pump, first to the shop and then to the local jobber supplying the pump.