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Thread: LC-1 heater power question...

  1. #1
    Senior Member ToplessTexan's Avatar
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    Question LC-1 heater power question...

    Anybody using the factory heater power and ground at the factory harness' O2 connector to power your LC-1 (red and blue wires)? If so, are you seeing any DTCs related to heater circuit performance? Reason I ask is Klaus' comment in this thread:

    http://www.innovatemotorsports.com/f...ead.php?t=2872

    I don't recall seeing complaints about DTCs so either it's not an issue or nobody pulls power from there.

    Thanks!
    K.

  2. #2
    Lifetime Member TAQuickness's Avatar
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    I did that at first. Never got a DTC (all of them are turned off), but the LC1 didn't work properly utilizing the NBO2 power/ground.

    In the end, I ran a dedicated power/ground back to the battery and used the NBO2 power/ground to togle a relay between the battery and LC1.


  3. #3
    Joe (Moderator) joecar's Avatar
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    I'm powering from the NBO2 vehicle connector, and it seems to work for me (I'm one of the lucky ones... ).

    I think the problem may be that the LC-1 requires better than 12.4V, and some vechicles show slightly less than this at the NBO2 connector (possibly due to a ground connection not being 100%...)... that's my unproven theory.

  4. #4
    Lifetime Member Garry's Avatar
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    works fine on my car, too with the stock heater power ...
    Garry Glendown * '17 Fifty 2SS MT * 99 Firehawk Convertible (for sale)

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    Senior Member ToplessTexan's Avatar
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    Thanks for the replies. I posted my thoughts about why no DTCs to the Innovate thread linked above. Of course, the DTC issue has nothing to do with any fussiness about voltages that the LC-1/LM-1 might have. (All of you don't have them turned off, right? )

    I've been conditioned to avoid at all costs even the most remote thought of size, weight, and power increases in my work, so I have a strong tendency to hate running extra circuits and having unused circuits hanging around when I don't absolutely have to. It's no biggie but it still makes me flinch.

  6. #6
    Joe (Moderator) joecar's Avatar
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    Klaus says the LC-1 switches it's WB02 heater circuit at 240 Hz, causing a current ripple in the NBO2 heater circuit (if that's how you have it connected).

    I checked the GM service Manual for 2001 F-body and 2003 Y-body, and found that none of the O2 DTC's get set directly due to the heater circuit malfunctioning (not even the "O2 heater performance" DTC's); all the reasons for setting any of the O2 DTC's have to do directly with the O2 output signal voltage (is it high, low, not switching, long time to active, etc...);

    looking at 2001 F-body wire diagram, the 02 heater voltage comes directly from the battery via the engine sensor fuse without involving the PCM, and the heater low goes directly to ground without involving the PCM;

    looking at Y-body wire diagrams, upto 2003, same thing, the PCM is not involved; from 2004 the PCM controls the heater circuit by switching the heater low to ground, which means it can monitor the voltage/current, but...

    Quote Originally Posted by GM Service Manual 2004 Corvette
    Heater Current Test
    • DTCs P0135 or P0155
      • The PCM detects that the affected HO2S Heater Current parameter is more than 3.125 amps or less than 0.25 amps.
      • The above condition is met for 10 seconds.
    • DTCs P0141 or P0161
      • The PCM detects that the affected HO2S Heater Current parameter is more than 1.375 amps or less than 0.25 amps.
      • The above condition is met for 10 seconds.
    It appears that this PCM doesn't care if the heater circuit has any current ripple on it as long as the current is within range.

    Edit: Klaus may have been referring to European ECM's being unhappy with the heater circuit.
    Last edited by joecar; January 17th, 2007 at 04:53 AM. Reason: Corrections

  7. #7
    Joe (Moderator) joecar's Avatar
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    Tex,

    You could temporarily connect the LC-1 to the NBO2 connector and see if it works...

    connect the LED (anode to black wire, cathode to white wire);
    when powered, it should flash for about 20 seconds and then stay on steady;

    connect a laptop to the LC-1, run the LM Programmer software, program various flatline voltages (cycle power each time) and see if you can measure these same voltages on the analog outputs (wait till the LED is steady on);

    if you wire the yellow and green wires to the NBO2 connector, run the engine and see if any DTC's are thrown.

    Joe

  8. #8
    Senior Member ToplessTexan's Avatar
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    Quote Originally Posted by joecar
    I checked the GM service Manual for 2001 F-body and 2003 Y-body, and found that none of the O2 DTC's get set directly due to the heater circuit malfunctioning (not even the "O2 heater performance" DTC's); all the reasons for setting any of the O2 DTC's have to do directly with the O2 output signal voltage (is it high, low, not switching, long time to active, etc...);
    That was my interpretation of what I found in my service manual as well.

    Quote Originally Posted by joecar
    Edit: Klaus may have been referring to European ECM's being unhappy with the heater circuit.
    I think he was just being appropriately careful. In general, there's no real reason to assume an arbitrary control module wouldn't directly monitor the circuit. I'm happy to see he responded more carefully than "sure, it'll work".

  9. #9
    Senior Member ToplessTexan's Avatar
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    Quote Originally Posted by joecar
    Tex,

    You could temporarily connect the LC-1 to the NBO2 connector and see if it works...

    connect the LED (anode to black wire, cathode to white wire);
    when powered, it should flash for about 20 seconds and then stay on steady;

    connect a laptop to the LC-1, run the LM Programmer software, program various flatline voltages (cycle power each time) and see if you can measure these same voltages on the analog outputs (wait till the LED is steady on);

    if you wire the yellow and green wires to the NBO2 connector, run the engine and see if any DTC's are thrown.

    Joe
    Thanks, sounds like a good plan. I'm just entertaining myself planning my harnesses, too cold to be hanging out in the garage right now. I can't see how it'd induce codes. At least for me.

  10. #10
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    Dunno if you got this sorted. This is a link to the LC-1 harness mods I made for my 2004 Monaro http://www.eneily.net/index_files/LC...%20Diagram.pdf
    2004 Monaro CV8 - 80mm BBK throttle body - 42lb Injectors - 1.8 Rockers - CAPA Long-Tube Headers- SLP Exhaust - Vortech Centrifugal S/C @ 7PSI- CAPA Intercooler - Bilstein Shocks - Wilwood 6-Pot/4-Pot Brakes - TyreWatch Monitoring - LC-1 Wideband - KAAZ Diff - Racelogic - 480RWHP

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