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giovani 6/21/2011
2007 Isuzu i-290 LS 4Cyl2.9L - Engine
reduced power lights is on
2 Answers
  • Spoon Sports
    Spoon Sports 6/21/2011
    Good day, i have heard this isuue a lot of times with this specific model, now there are several solutions here is the thing, would like to check all those solutions? I dont think thats a good idea, i saw one guy came up with 6 codes.

    My suggestion is to get it scanned then get back to me

    Please do not reply by clicking "Reply". reply by clicking "Answer Question" so it will reflect in my INBOX so i can get back to you if something comes up
  • Spoon Sports
    Spoon Sports 6/21/2011
    Here is what my friend Rhick has to say

    After replacing the TPS (Throtle position sensor) with a new one and getting the same codes as before I assumed that I must have a wiring problem. It stands to reason that if the computer is sending out the same error codes before and after part replacement then there must be an information block. I started with the grounding issues because good grounding is essential. Earlier I found a broken bolt in the intake manifold that held a ground. It obviously looked secure but wasn't. I moved the ground to a secure bolt and for a short while the problem did resolve. Later the problem came back. This again seemed to point me in the direction of a wiring problem because there was an intermittent issuing going on. I cleaned and checked every other ground wire, added new grounding from the battery to the engine, and replaced the battery cables but that didn't help this time. I moved next to the computer. I wanted to check that every wire was secure in the socket and that it wasn't broken. Because there are so many wires it is a daunting task. I removed both the blue and red sockets running to the computer. I pulled both directions on every wire on the blue socket and all the wires were secure. I moved next to the red socket.

    When I was about half way through that group of wires I pulled on one that seemed much less tight. I pulled a little harder and it slid right out of the harness. EUREKA! Now I had to find the other end of the break. I could by examining the end of the broken wire that it was shorted and as I dug through the bundle I found the other end. It was fused to another wire which was also partially if not completely shorted as well and the two had melted together somewhat. Fortunately I was able to identify which wire went where because both wires were color coded the same. I soldered the wires back together, reconnected the plugs to the computer and started the car. The reduced power light immediately went off. The engine accelerated for the first time in weeks and after a few starts the check engine light cleared and also turned off.

    My theory is that the bad ground allowed an imballance of current in the circuit and the guilty wire overheated right in the middle of the harness bundle where the most heat would be prone to be concentrated and where the bundle was packed tightest together perhaps weakening the insulation protection and eventually a direct short resulted.

    I hope this helps someone else with a similar problem because I had this car in two very competent shops and neither one of them could figure out the problem. I spent hundreds of dollars in diagnosis but in the end they told me I needed to take it to an Isuzu dealer who had the tailored diagnostic equipment. The closest dealer to my town is 150 miles away so I either had to trailer the car there or fix it myself, which is what I did.

    I say the mechanics relied too much on the data coming from the computer and missing the possibility that the problem was not a component related failure but a wiring failure. Good luck to the rest of you.

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