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Thread: Error code - "Load signal circuit" help needed (4Y-E)

  1. #1
    Chookhouse Chooning Automotive Encyclopaedia Hen's Avatar
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    Default Error code - "Load signal circuit" help needed (4Y-E)

    The background:
    I've just installed a 4Y-E (ex 89 Tarago) into my folks YH71 Hiace camper van. It runs well and has decent power (read: better than the tired 3Y-C).

    The problem:
    The fuel consumption seems to be high (read: lamentable). So I checked for error codes and it spat a code 11. This is "Load signal circuit" according to the Gregorys manual. But I really have NFI what this means.

    From the layout of the manual and other codes I think this means the A/C load signal is bad. The engine is AFM and there is a seperate AFM error code, and speed sensor error code too.

    I investigated the A/C input pin. It is connected to the positive side of the A/C magnetic clutch coil. According to the manual, this wire should have 12V on it when the aircon is switched on (and so I assume 0V when the aircon is switched off). However in the van the aircon is switched off (not operational yet) and so this wire has 0V on it. And yet the ECU still spits the code. Disconnecting the pin from the ECU still gives the code. And yes, I deleted codes between checking things.

    The question:
    Can anyone clear up what this "Load signal circuit" error really means. And can anyone suggest anything more to check regarding this problem?

    Thanks
    Hen
    I need a working 4AGE bottom end. Pref smallport GZE, but all others considered. Also complete motors.
    Drift Volvo. Was fun. 2JZ next time.

  2. #2
    Backyard Engineer Domestic Engineer airfireman1's Avatar
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    Hi this may or may not help you. I have an efi diagnostics and repair manual and you are right code 11 is a/c load signal. This is so that when the a/c is on the ecu can detect this and adjust the idle up to compensate for the extra load. the book also show an a/c amplifier but does not state what its purpose is
    This book states 1.check that the a/c is operating properly 2.when the a/cis on check that 8-14 volts is available between terminals E1 and a/c at the ECU wiring connector. If 8-14 volts is available renew the ECU.
    Does not sound too helpfull.
    But that will not be the reason for high fuel consumption normally
    The main reasons are 1. ignition system 2.airflow meter 3.injectors 4.Fuel supply 5.throttle position sensor 6.coolant temp sensor.

  3. #3
    Chookhouse Chooning Automotive Encyclopaedia Hen's Avatar
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    That is almost precisely the passage regarding the aircon system from my Gregorys manual. And yes, I think the high fuel consumption may be unrelated to this code. However now I have found it I really want to get rid of it.

    Thanks for the input
    Hen
    I need a working 4AGE bottom end. Pref smallport GZE, but all others considered. Also complete motors.
    Drift Volvo. Was fun. 2JZ next time.

  4. #4
    Junior Member Domestic Engineer
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    11 Switch signal fault

    Possibility of:
    No idle switch signal
    No neutral drive switch signal (A/T)
    A/C switch circuit
    A/C switch
    A/C amplifier
    ECM
    Throttle position sensor and circuit
    Neutral start switch (M/T).


    this is extracted from my repco software

  5. #5
    Junior Member Grease Monkey
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    This may or may not help; different car, same problem.

    Our SV21 was running like sh1t with the A/C on.

    I was getting code 51 ( Load signal circuit)

    I checked everything,ECU, Amplifier, including connectors & wires with the multimeter. All checked out fine.

    It turned out to be a dirty, carboned up ISC valve ( dirty to the point where it couldn't function)

    Cleaned that, reset ECU, everything's fine now. Runs beautifully.

    May be helpful???
    Cheers.

  6. #6
    Junior Member Domestic Engineer mic*'s Avatar
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    Quote Originally Posted by sideshow
    11 Switch signal fault

    Possibility of:
    No idle switch signal
    No neutral drive switch signal (A/T)
    A/C switch circuit
    A/C switch
    A/C amplifier
    ECM
    Throttle position sensor and circuit
    Neutral start switch (M/T).


    this is extracted from my repco software
    Good info, makes it a rather ambiguous code tho eh...

    Interesting that the SV21 threw a code 11 with a clogged ISCV... My intepretation of that is that you may get the code from any problem which causes an irregularity when the engine tries to compensate for a load. So, could it be possible that any excessive load could cause the engine to try to work outside its range to compensate for and subsequently throw the error code...

    Im leaning towards TPS setting from the above list. Could explain some economy woes too?
    meh...

  7. #7
    Junior Member Grease Monkey
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    I'm not too sure about the economy side of things, as I'm not familiar with the 4Y-E.

    I think your theory on how the code is generated seems logical though.

    To be totally honest, I'm a novice when it comes to the EFI side of things. I usually need a book beside me.

  8. #8
    Junior Member Domestic Engineer
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    its a tarago

    they were never good vehicles for fuel economy

    maybe its time to update to a new hilux

    i am

    they kick ass hehehehehehe

  9. #9
    Chookhouse Chooning Automotive Encyclopaedia Hen's Avatar
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    OK, just home from a couple of hundred kms in the van. And I think the fuel consumption problem is solved. It turned about 11-12l/100km on the highway. Which I am happy with given that it is lugging about 2tonnes of unaerodynamic metal around. Turns out the ECU was full of error codes (had never reset them since getting it running) so was probably in uber-rich mode.

    I'm still getting code 11 though. I've dug around as much as I can and really don't think there is anything wrong with the A/C circuitry.

    As for the ISCV, the 4Y runs an idle up VSV which I can hear switching and hear working (revs rise and fall as it switches).

    Sounds like a phantom problem in need of more multimeter time.
    Hen
    I need a working 4AGE bottom end. Pref smallport GZE, but all others considered. Also complete motors.
    Drift Volvo. Was fun. 2JZ next time.

  10. #10
    Chookhouse Chooning Automotive Encyclopaedia Hen's Avatar
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    Well, one year later I discovered the TPS was never plugged in (my excuse is that it is impossible to see/get to it in a van).

    Connected it and the Code 11 disappears. The ECU is now happy.

    Hen
    I need a working 4AGE bottom end. Pref smallport GZE, but all others considered. Also complete motors.
    Drift Volvo. Was fun. 2JZ next time.

  11. #11
    Mad****** Grease Monkey FASTFOO's Avatar
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    Default Re: Error code - "Load signal circuit" help needed (4Y-E)

    LOL nice one
    11-12l/100 is not bad with no tps.
    MATT.

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