A pile of codes, all at once... | FerrariChat
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A pile of codes, all at once...

Discussion in '348/355' started by Redlyne_mr2, Sep 29, 2025 at 4:41 PM.

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  1. Redlyne_mr2

    Redlyne_mr2 Formula Junior

    Aug 5, 2009
    481
    Calgary, Alberta
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    Ryan D
    #1 Redlyne_mr2, Sep 29, 2025 at 4:41 PM
    I have a CEL that I always attributed to having test pipes, I've recently noticed some sluggish performance so I decided to pull the codes and here is what came up:

    1. P1445 Cat convertor temp (is this related to the test pipes?)
    2. P1449 Cat convertor temp (related to test pipes?)
    3. P1148 PWM Cooler voltage protector
    4. P0432 Main catalyst efficiency below threshold bank 2 (related to test pipes?)
    5. P0422 Main catalyst efficiency below threshold bank 1 (test pipes?)
    6. P1115 lhb outside temperature sensor

    Are Cat ecus still needed when I have test pipes? I did replace my thermocouples not long ago but that may have been money wasted.

    Any feedback would be appreciated so I'm not just throwing parts at the car.

    Thank you
     
  2. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,465
    Los Angeles
    #2 Targatime, Sep 29, 2025 at 7:37 PM
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  3. Qavion

    Qavion F1 World Champ
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    Ian Riddell
    #3 Qavion, Sep 29, 2025 at 8:34 PM
    Since no one has the codes for the 5.2 Motronic system, generally we use the 360 codes:

    For P1148: Input Signals for Charging Detection (Bank 2)
    For P1115: 02 Sensor Heater Circuit (Upstream Catalyst) (Bank 1, Sensor 1)

    The F355 and 360 vary somewhat with regards to O2 heater control. The F355 only controls/monitors the heat in pairs (i.e. the precat O2 sensor on both banks or the post cat O2 sensors on both banks), so I'm not really sure what this code signifies for the F355.

    There are no diagnostic recommendations for P1148 on the decoding chart, so no clues as to what it means. Low battery or key power voltage?
    Live battery voltage is seen on pin 26 of the ECU connector.
    Key power is seen on pin 56 and 54. Pin 54 will only get power if injector relay "M" in the passenger footwell is energised. To get the relay to energise with the ECU plug disconnected, you'll have to jumper the relay (pins 30 and 87). Key power comes through the 9 pin plug near the main ECU plug. Pin/wiring defects do occur on this plug from time to time. Check the pins for security/cleanliness. Battery power goes through the 14 pin plug nearby.
     
  4. Redlyne_mr2

    Redlyne_mr2 Formula Junior

    Aug 5, 2009
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    Calgary, Alberta
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    Ryan D
    #4 Redlyne_mr2, Sep 30, 2025 at 4:38 PM
    Thanks for the info, I did try installing those dummy units from Technistrada and my SDL light came on full time. I also have the downstream o2 sensor spacers.

    My game plan is to clear the codes, drive the car and see what codes come back. Once that happens I'll note the codes, try to reinstall the dummy units and then see what happens.

    By the sounds of it, as long as I have those dummy units installed properly then I dont need the thermocouples or cat ecu any longer which solves most of the problems.
     
  5. Qavion

    Qavion F1 World Champ
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    #5 Qavion, Sep 30, 2025 at 4:54 PM
    Doesn't make a lot of sense. I haven't heard of any Technistrada dummy units being faulty (because of their simplicity) and Motronic ECU faults are relatively rare. 1445 and 1149 refer to bank 1 and bank 2 respectively.

    Did you clear the codes after you installed the dummy units?
     
  6. Redlyne_mr2

    Redlyne_mr2 Formula Junior

    Aug 5, 2009
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    Calgary, Alberta
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    Ryan D
    #6 Redlyne_mr2, Sep 30, 2025 at 5:37 PM
    I thought so too, as did the owner of technistrada. All I know is they came on the moment i installed them, perhaps I installed them wrong so I'll take my time on this one and see what happens.
     
  7. ShineKen

    ShineKen Two Time F1 World Champ
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    #7 ShineKen, Sep 30, 2025 at 7:30 PM
  8. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,465
    Los Angeles
    #8 Targatime, Sep 30, 2025 at 9:58 PM
    You probably plugged one of them into thermocouple in the bypass pipe. There are three possible places to plug them in, only two of them are correct. Make sure to trace the wiring...
     
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