Crank sensor and PCM History
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Northstar Engines and System Technical Discussion Discussion, Crank sensor and PCM History in Cadillac Engine Technical Discussion; Gen I PCM = non OBD II inside the car and the size of a football field. Gen I Crank ...
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    AJxtcman's Avatar
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    Crank sensor and PCM History

    Gen I PCM = non OBD II inside the car and the size of a football field.
    Gen I Crank Sensors. A and B the same. fits 93 to 99. two wire sensors.
    Gen II PCM 96 to 99 OBD II
    Gen II Crank Sensors 2000 to 2005. They are three wire sensors and they have had many updates. locacted in the front near the oil filter.
    Gen III PCM 2000 to 2003 several part numbers all supercede to one.
    Gen IV PCM 2004 and 2005. small with three wire connectors
    Gen III Crank sensor. 2006 to 2008. just 1 sensor located near the starter. Three wire.
    Gen V PCM 2006 to 2008 even smaller, but the most powerfull PCM GM uses.

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    Re: Crank sensor and PCM History

    I could not find 1 TSB or PI on 93 to 99 Crank Sensors. I have replaced just a handful.

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    Re: Crank sensor and PCM History

    Service VME - 4.6L ( L37, LD8 ) Northstar Engine Crank Sensors - kw DTC MIL stall #PI01478 - (10/30/2003)
    This service VME is to give you a heads up on an emerging parts concern. It concerns FWD Northstar crank sensors on 2000 to 2003 vehicles.
    The new supplier of crank sensors started supplying production at the start of the 04-model year as well as supplying SPO with service parts in September. .
    .
    00-03 Cadillac EB KB 4.6L LD8 L37 Engine Northstar Updated Crankshaft Sensors - kw DTC MIL driveability #PIP3036 - (06/29/2004)
    12575481- UPPER-(GRAY IN COLOR)
    12575482-LOWER-(BLACK IN COLOR)
    .
    .
    Subject: Intermittent Engine Idle Instability, Hard/No Restart or Decel Stalls, SES Lamp Illuminated, DTCs P0335, P0336, P0385, P0386 or P1599 may be Set (Diagnose and Repair) #02-06-04-019 - (04/09/2002)

    Models: 2000-2001 Cadillac DeVille, Eldorado, Seville 2001 Oldsmobile Aurora
    with 4.0L or 4.6L Engine (VINs C, Y, 9 -- RPOs L47, LD8, L37)

    Correction
    If the vehicle has any of the crank sensor codes P0335, P0336, P0385, or P0386 set, then the following should be done:

    • Inspect both of the crank sensor terminals for signs of poor connection or corrosion of both crank sensors. Pin drag test all four terminals.

    • Inspect the crank sensor circuit wires for signs of damage.

    • Inspect the crank sensor circuits at the PCM for poor connections. The crank sensor terminals should also be drag tested.

    • Remove the crank sensors and check for any debris on the sensor.

    • Verify crank sensor location (A on the bottom and B on the top) and verify that the sensor circuit wires are in the correct cavities.

    • Inspect the date code on the sensor. If it is before 0276, replace the crank shaft sensor and perform case learn.

    • If the date code is past 0276, verify the PCM grounds. A voltage drop test should be less than 20 mV.

    • If the PCM ground circuit verification is acceptable, then follow published PCM diagnostics.

    If the vehicle has an idle or decel stall, or near stall concern and only has DTC P1599 set, then the following should be done:

    • Verify the system power and ground connections for the PCM.

    • Verify crank sensor location (A on the bottom and B on the top) and verify that the sensor circuit wires are in the correct cavities in the harness.

    • Remove the crank sensors and check for any debris on the sensor.

    • Verify that the fuel pressure regulator is not leaking fuel past the diaphragm.

    • Perform the injector balance drop test and verify even pressure drops on all injectors.

    • Inspect and clean the EGR passages, as necessary.

    • Inspect and clean the IAC passages, as necessary.

    .
    .
    .
    Did GM know of a Crank sensor problem. YES. They had updated sensors and then had to swicth suppliers. Who is at fault? GM's design or bad supplier?

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    Re: Crank sensor and PCM History

    First Gen crank sensors.
    Crankshaft Position Sensors and Reluctor Ring
    The two crankshaft sensors are located on the front bank (BANK 2) of the engine block between cylinders 4 and 6. Crankshaft position A sensor is located in the upper crankcase and crankshaft position B sensor is located in the lower crankcase. Both sensors extend into the crankcase and are sealed to the engine block with O-rings. The crankshaft position sensors are not adjustable.

    The magnetic crankshaft position sensors operate similar to the pickup coil in a distributor. When a piece of steel (called a reluctor) is repeatedly moved over the sensor, a voltage will be created by the sensor that appears to go On-Off-On-Off-On-Off. This On-Off signal is also similar to the signal that a set of breaker points in a distributor would generate as the distributor shaft turned and the points opened and closed.

    The reluctor ring is cast onto the crankshaft between the #3 and #4 main bearing journals. The reluctor ring has 24 evenly spaced notches or air gaps and an additional 8 unevenly spaced notches for a total of 32.

    As the crankshaft makes one complete revolution, both the A and B sensors will produce 32 On-Off pulses per revolution. In addition, the A sensor is positioned 27 degrees of crankshaft revolution before the B sensor. This creates a unique pattern of On-Off pulses sent to the ignition control module so that it can recognize crankshaft position.

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    Re: Crank sensor and PCM History

    Gen 2 Crank sensors. This is a picture of the first version that fail all the time. The top sensor is tan. The updated sensors have a GREY top sensor and the bottom remains black
    .
    Crankshaft Position Sensors
    The PCM uses dual crankshaft position (CKP A and CKP B) sensors to determine crankshaft position. The CKP sensors are mounted in the engine block approximately 21.5 degrees apart from each other. Three wires connect each CKP sensor to the PCM. The PCM supplies an ignition voltage and a ground for each CKP sensor. During engine rotation, a slotted ring, machined into the crankshaft, causes the sensors to return a series of ON and OFF pulses to the PCM. The PCM uses these pulses to decode the position of the engine crankshaft.

    The PCM uses two basic methods of decoding the engine position: Angle Based and Time Based (using either CKP A or CKP B sensor input). During normal operation, the PCM uses the angle based method. In order to operate in this mode, the PCM must receive signal pulses from both CKP sensors. The PCM uses the signal pulses to determine an initial crankshaft position, and to generate MEDRES (24X reference) and LORES (4X reference) signals. Once the initial crank position is determined, the PCM continuously monitors both sensors for valid signal inputs. As long as both signal inputs remain, the PCM will continue to use the angle based mode.

    When either CKP signal is lost, the PCM will compare the MEDRES signal to the camshaft position (CMP) sensor signal. If the PCM detects a valid CMP signal, and the MEDRES to CMP signal correlation is correct, the PCM determines that CKP sensor A is at fault. However, if the MEDRES to CMP correlation is incorrect, the PCM determines that CKP sensor B is at fault.

    If the PCM detects a loss of signal for CKP sensor A, DTC P0335 will set. The PCM will switch from angle based mode to Time Based mode B using CKP sensor B signal input. If the PCM detects a loss of signal for CKP sensor B, DTC P0385 will set. The PCM will switch from angle based mode to Time Based mode A using CKP sensor B signal input. A noisy signal input from either CKP sensor will cause the ignition system to re-sync. If the number of ignition system re-sync is more than a calibrated amount, DTC P1372 will set.

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    Re: Crank sensor and PCM History

    Quote Originally Posted by AJxtcman View Post
    Gen I PCM = non OBD II inside the car and the size of a football field.
    .
    They might be the size of a football field, but they don't need to wait 2 months (or more?) to get tuned. .
    I think I waited 4 days for my chip.



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    Re: Crank sensor and PCM History

    Thanks AJ. Enjoy all of these side conversations regarding parts updates and the like.

    Regarding the updated GenII sensors -- you said the upper changes from TAN to GREY, but the bottom remains BLACK. Does this mean that the bottom sensor was not updated, or that the updated sensor is also black, meaning you can't distinguish by color?

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    Re: Crank sensor and PCM History

    They both are updated. They both had a date code that they had us look for. Then they switch suppliers because of that part failure rate.

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    Re: Crank sensor and PCM History

    Quote Originally Posted by clarkz71 View Post
    They might be the size of a football field, but they don't need to wait 2 months (or more?) to get tuned. .
    I think I waited 4 days for my chip.


    What is that thing for??
    I think I saw that in a Commodore 64.
    That PCM is sooooo sloooow you can never run a good time in it.
    What is the speed of that PCM????
    BTW I have many PCM's running my programs.
    I think you are missing my point. I have at this point just seen 2
    The first I was requested to hold on to.
    The second just arrived.
    .
    I think you better think about who is taking advantage of who!!!
    I sent out a PCM in good faith to someone who says that they have sent one to me.

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    Re: Crank sensor and PCM History

    Quote Originally Posted by AJxtcman View Post
    What is that thing for??
    I think I saw that in a Commodore 64.
    That PCM is sooooo sloooow you can never run a good time in it.
    What is the speed of that PCM????
    .
    It works well enough to make 275 hp, just like every Y engine after it. Isn't the GXP Benneville 275 hp? Anyway, I'm just messing with you dude. Mercedes tech vs Caddy tech. You know

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    Re: Crank sensor and PCM History

    Quote Originally Posted by clarkz71 View Post
    It works well enough to make 275 hp, just like every Y engine after it. Isn't the GXP Benneville 275 hp? Anyway, I'm just messing with you dude. Mercedes tech vs Caddy tech. You know
    You do know that you could have had your Prom/MemCal updated at the dealer? You could have had the torque management turned off and a bunch of other updates done to it. TCC functions.

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    Re: Crank sensor and PCM History

    The only reason I replaced the prom was to get rid of the 112 mph speed limiter. I've had it up to 145 mph (by the speedo) since I replaced it. I was more then satisfied with the power stock, although it does run better with the Fastchip. Overall it runs pretty good for a Y car.

    I still have my stock prom, what are these updates?

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    Re: Crank sensor and PCM History

    Quote Originally Posted by clarkz71 View Post
    The only reason I replaced the prom was to get rid of the 112 mph speed limiter. I've had it up to 145 mph (by the speedo) since I replaced it. I was more then satisfied with the power stock, although it does run better with the Fastchip. Overall it runs pretty good for a Y car.

    I still have my stock prom, what are these updates?
    One update was a high speedlimiter.
    .
    I have never done one, but I can look into it.
    PM me your VIN.

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    Re: Crank sensor and PCM History

    I would think to have the mph limiter raised by the dealer you would need the correct tires for the speed increase.

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    Re: Crank sensor and PCM History

    I Installed some more crank sensors today. They are Made in Japan. Denso?
    I noticed the ends are not cut at a slant.

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