Automotive 101 – Diagnosing Technology
Following a lengthy hot summer time along with a mild situation of authors block, I will alter the tone a little within my latest publish. It is quite lengthy, somewhat technical, but can serve as a look to some day within the existence of the automotive specialist- business proprietor, the technologies we cope with and also the peculiar problems we face generally.
I lately serviced a 1999 Suzuki Grand Vitara using the customers concern of the inability to pass Delaware Condition inspection. The reason behind the inspection failure was that three of the OBDII computer monitors weren’t set. The monitors which had not occur a passing condition were oxygen sensors, catalytic ripper tools and evaporative system. Delaware Automobile provided the dog owner a printed copy from the “drive cycle” needs to permit the monitors to operate for your specific vehicle. Who owns the automobile attempted 3 more occasions within the length of 2 several weeks while driving as many as 1043 miles in order to get these monitors to create. Each retest created exactly the same failure results.
That will help you comprehend the technology and connected terminology within the previous paragraph and also the following story, I’ll first explain individuals terms in depth
• OBDII- Aboard Diagnostics Generation 2- all vehicles created since 1996 were engineered with this particular technology within the computer to satisfy Federally Mandated Emission standards.
• Monitors- Self tests done by the ability train control module (computer) around the various systems that effect emissions output in the vehicle in addition to control the operation and gratifaction from the vehicle. Whenever a monitor “sets”, it’s passed the exam.
• Drive Cycle- Conditions that has to be met for that various self tests (monitor) to create. A couple of examples could be engine temperature, vehicle speed, engine load, outdoors temperature, gas tank level and internal tank pressure.
I connected our diagnostic scanners (a device that cost $6000 to buy and $2000 yearly to help keep updated) and performed a fast scan from the computer to check on for codes. I additionally verified the monitors which were not set based on the failure records from Department of motor vehicles. There have been no problems kept in either current or pending status and also the 3 monitors formerly pointed out hadn’t run. Overview of current printed manufacturer technical bulletins coupled with canvassing the automotive forum we fit in with, offered no quick solution with this problem.
Using the diagnostic scanner still connected I decided all 4 oxygen sensors to watch their activity. Using the vehicle running, among the sensors was operating in a fixed current instead of different because they should, the studying wasn’t outdoors the parameters to create a fault code to have an apparent deficient sensor. To isolate the reason for this fault, I back probed the sensor to check the current, then tested the current directly in the computer harness connector and lastly bypassed that circuit within the wiring harness having a jumper wire to ensure and compare the different readings through the circuit. Just before these tests, the potential cause would be a faulty oxygen sensor, faulty wiring for your sensor circuit or perhaps an internal fault within the computer. Ultimately I replaced the unsuccessful oxygen sensor.