husker123 Posted December 31, 2011 Report Share Posted December 31, 2011 1995 Cadillac Seville SLS 4.6l Northstar 32v PCM error codes P012, P053 Problem 1) car has an extremely hard time starting. it will crank constantly but never turn over. Problem 2) eventually (lucky) the car will start, it then idles at 800 RPMS and will sometimes surge and drop back and forth, the car after a while will just shut off the engine. Also while driving the car has surged revs up and down too. I have replaced all 4 coil packs in response to code P012 but that seemed to not do anything. Any other ideas? I see this problem all over these forums and i have been working at it for around 6 months with no solution. THanks, Link to comment Share on other sites More sharing options...
Texas Jim Posted December 31, 2011 Report Share Posted December 31, 2011 P012 = no 4X signal from ignition control module. The first thing I would do is check "ALL" wires going "TO" and "INSIDE" the distributor. If the wires are good... replace the ignition control module... about 20/25 bucks. Link to comment Share on other sites More sharing options...
husker123 Posted January 1, 2012 Author Report Share Posted January 1, 2012 P012 = no 4X signal from ignition control module. The first thing I would do is check "ALL" wires going "TO" and "INSIDE" the distributor. If the wires are good... replace the ignition control module... about 20/25 bucks. I have Coil Packs not the distributor. I replaced those. Just got done spending 225 bucks on an ICM and the same problem exists. The car will crank it just won't turn over. We also replaced the crankshaft position sensors today as well and that did not fix anything wither. Link to comment Share on other sites More sharing options...
BodybyFisher Posted January 1, 2012 Report Share Posted January 1, 2012 First off, don't just parts replace, it gets expensive. I would check the cam sensor connection and replace the cam sensor if its connections are ok, since you already replaced the IC module. But check all connections and grounds closely. I do not see the crank sensors being at fault here due to the crank sensors being associated with 24x signals. 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. Camshaft Sensor The camshaft position sensor is located on the rear cylinder bank (BANK 1) in front of the exhaust camshaft. The camshaft position sensor extends into the rear cylinder head and is sealed with an O-ring. The camshaft position sensor is not adjustable. As the rear cylinder bank exhaust camshaft turns, a steel pin on its drive sprocket passes over the magnetic camshaft position sensor. This creates an On-Off-On-Off signal sent to the ignition control module similar to the crankshaft position sensors. The camshaft position sensor produces one On-Off pulse for every one revolution of the camshaft or every two revolutions of the crankshaft. This allows the ignition control module to recognize camshaft position. Ignition Control Module The Ignition Control (IC) module is located on top of the rear camshaft cover. The IC module performs several functions: It monitors the On-Off pulses produced by the two crankshaft and one camshaft position sensors. It creates a 4X and 24X reference signal (4X REF HI and 24X Crank) sent to the PCM for ignition control. It creates a camshaft reference signal (CAM HI) sent to the PCM for fuel injection control. It provides a ground reference (REF LO, CAM LO) to the PCM. It provides a means for the PCM to control spark advance (BYPASS and IGNITION CONTROL) called IGNITION CONTROL MODE. It provides a limited means of controlling spark advance without PCM input called MODULE MODE. The IC module is not repairable. When a module is replaced the remaining components must be transferred to the new module. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
husker123 Posted January 2, 2012 Author Report Share Posted January 2, 2012 I have given up on the P012 code. Replacing everything did not solve the problem. We decided to go a different route and check the fuel line. We couldn't smell gas going into the engine, so we put it directly into the carburetor. And it started right up. I will look into the cam shaft position sensors but I personally feel that the surging is coming from a bad fuel filter and/or a bad Fuel control module. Link to comment Share on other sites More sharing options...
Ranger Posted January 3, 2012 Report Share Posted January 3, 2012 We couldn't smell gas going into the engine You won't. It's fuel injected. we put it directly into the carburetor You don't have a carburetor. Only a throttle body. And it started right up Zero fuel pressure = bad fuel pump. Link to comment Share on other sites More sharing options...
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