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P0358 07 Silverado

  1. I have an L33-5.3L Silverado Classic from 2007. I have a P0358 code that I cannot get rid of. I have replaced the coil, the coil set (4 coils on that side) and the metal they are fastened to and the harness on the mounting bracket. The spark plug wire, the spark plug and the ECM. I even replaced the engine (for a separate reason). There is no misfire. This diagnosis has been confirmed by three separate people.
    I think my problem is on the detection side. I would like to know how the vehicle detects problems with this circuit. What position in the circuit is monitored? Which computer? Which harness?
  2. Well, this for me seems to be a loaded question. My french may get in the way.

    Ok, Po358, so circuit in question is cyl 8.

    This did not make sense to me. You replaced THE coil, THE coil set '4 coils on that side'

    Which is it?

    And what is the metal they are fastened to?

    The ECM has an individual IC circuit for each separate cylinder, 1 through 8. The algorythm is quite slow, 1 second to detect a fault in the IC circuit. Most likely a grounding issue from a driver in the ECM if all ohm checks check out.

    That has been a big problem with those Mosfets. My kniowledge is limited here, but I do remember an article relating to using bipolar transistors for the IC circuits in these GM ecu/ecm's.
  3. Pay special attention to step 5 of the following PDF. The frequency will tell you if you are having a transistor fail. In both cases, you are probably looking at a bad ECM if all wiring checks are ok. In step six, just a repeat in ohms to make sure integrity of wiring, and hits home again, probably a faulty ecm on 8th cyl IC driver internal to ECM/ECU.

    See ace 0 pdf below. Hope you have a scanner and good multimeter and skills. Cuz your question left me to believe you have some knowledge, but needed more in depth help.
  4. You will see 4 pin on each coil, pay special attention to the ground side of the IC circuit. That is most likely were you will determine if it is in fact a bad ECM. Hint.:cool:
  5. I read you have replaced the ECM. Coil, and also the 4 coils on that bank. Am I reading correctly?

    When the ECM was replaced, was it with a new unit? Or a junk yard unit?

    If new, how was it flashed?

    How can this be? Every P035# code is almost always accompanied by a P030# misfire code. Something is eluding
  6. Also, if you are serious in your endeavour to fix this, plz tell us what type of equipment was used to program that NEW ECU.

    That might be a huge tell tale.;)
  7. As for this, the ECU uses the ground for detection as that is what triggers the drivers. Without going into a lengthy discussion on CAN line and BUS line, most detection in transistor driven common rail ground is done through ground circuitry since the rail monitoring for these two communication lines are very similar. MUX line is a bit different, but that is for another time and different discussion.

    Snapshot of what I mean, notice common rail ground.

    Screenshot (59).png
  8. Thanks for the replies. I appreciate your time and thoughts. It is a loaded question. I am not sure what is going on and I have tried to investigate on my own.
    I have replaced the coils, the actual coil for each cylinder with a brand new one from an OEM parts store.
    I have purchased from a junkyard a set of coils with the mounting bracket that holds all 4 coils to the valve cover on the passenger side, it also came with the wiring harness for the coils, the main harness was cut from the donor L33 engine (The Replacement Engine :) ).

    (I have the driver's side set also, but I have not replaced that set yet.) I will look into the bipolar transistors. I have replaced the ECM. The same thing happens with the brand new ECM as when I reset the codes with my original ECM, it is fine in neutral in the parking lot, but once I am driving the P0358 code comes back.

  9. I have occasionally had the P0330 where it does call for a misfire. But mostly the P0358 alone, pending.
    I have taken it to a mechanic and the actual diagnosis was that the #8 circuit is at a higher frequency than normal 3-20Hz; in my 4WD truck it was between 20-50Hz. So I bought the new ECM and have not had it re-analyzed, but the same code came back with the new ECM within minutes, just the same pattern as with the original ECM fine in park but SES when in gear.
    The new ECM I bought on line as a brand new unit from a LS-engine place. They did the flashing.
    With the exact same P0358 code coming back with a completely new and different ECM unit, I would like to eliminate the ECM as a potential culprit, unless you feel like there is a testable hypothesis. :)
    I am going to use your PDF (the 2WD and 4WD should be the same) and see what numbers I can gather today. I do have a voltmeter and I know how to use it, but I do not have one that reads frequency. I will report back when I have some data.

    Where is the actual ground wire that they all connect to?
  10. The old engine had #4 cylinder exhaust lifter roller go bad. I left the sensors in the old engine, but I am using the same intake as the old one.
  11. the 8th character of vin# is B ? let us know.
    My thoughts - being only 1 cylinder I would double check the electrical connector on #8 - tight, corrosion free, no bent loose connectors/pins, A wire piercing tool and shaking tugging harness would show a change if a wire issue - often wire issues will be within @3inches of the connector - the connector is sold separate try NAPA.
    How have several people confirmed no misfire - a scanner in mode 6 or ?

    Your last post - You have high Hz next what is voltage on IC circuit? If you can not read Hz how did you post the range?
    Have you swapped coils to easy a way to confirm coil or wiring to ignore ...

    IMPORTANT - vehicle is stock, AC Delco coils, plugs etc? No modifications - it all matters?
  12. Depending on where you read, this is a code for coil "H" or coil "8", with the further implication that coil 8 is for cylinder #8. However, some DIS systems label the coils A-H according to the firing order. Thus "H" would be the #3 cylinder, 8th in the firing order. Are we sure which coil is being flagged?

    I don't mean to "drag this into the weeds"; point is, replace the coils on the odd bank, since you already have them.
  13. where is the ground wire they all connect to ...........................2,4,6,8 will splice and terminate at G102 item 2 and 3. see attachment
    Th other wire goes to PCM/ECM. low reference AKA ground. PCM connector C2 terminal 61 - do you need a pinout of PCM?
  14. Yes, it is a B-VIN truck with an L-33. I took the truck to a mechanic who diagnosed the high frequency. I trusted his word, I am not personally sure that it was high frequency. He said that no misfire was detected. His report did not include the instrument he used to look for the misfire, I am sorry I cannot provide that detail. I then took it to two additional mechanics with this and all suggested a new ECM. There has not been a drop in performance at all.
    So I got a new ECM, within 5 minutes, upon driving it, the same P0358 code came back. I have not had this diagnosed, with the new ECM.
    Stock with AC-DELCO parts and K&N air filter.
    I like where billr is coming from. I will change the opposite bank of coils also.
    I appreciate kev2 the place for G102. I will make sure it is a snug connection and a good ground. Maybe connect it straight to the battery.
  15. this code suggests that the coil control wire to ECM* is open, grounded or shorted to voltage.
    The pink wire supplies 12v to coil terminal D, the control wire terminal C goes to ECM - it will have 12v and when ECM grounds coil the voltage will drop - it is these 2 voltages that are monitored.
    One of them is out of the expected range - you have 2 engines, 2 ECM, new coils, different plugs, wires, doing the same code.
    Your coil wire harness is the vehicle original - not a cut and patch?
    $.02 and thinking out loud-
    I would look at the elec connector at #8 do the piercing ck and shake wiggle tug the connector and harness.
    Be sure the secondary is not near the connector as ignition leakage could cause a spike on IC wire.
    How does plug look? same as others?
    Charging system - Bad diodes would not be on 1 coil only. But an easy ck.
    Compression #8 low may keep IC Voltage high.
    We just saw this on a colleagues car - new is not always good - swap coils.