RJSUS Posted March 9, 2007 Report Share Posted March 9, 2007 Are 741 and 1520 related error codes?? Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted March 9, 2007 Report Share Posted March 9, 2007 DTC P0741 TCC System Stuck Off DTC P1520 Transmission Range Switch Circuit 1996 code list: http://www.caddyinfo.com/1996stsdtclist.htm Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
JimD Posted March 9, 2007 Report Share Posted March 9, 2007 Not Directly. P1520 indicates the PCM is confused by the input from the transaxle range switch. P0741 means the PCM has detected torque converter clutch (TCC) slip under conditions where there should be no slip. The service manual does not provide enough detail about the internals of the PCM to be able to know if the presence of P1520 will prevent the TCC from activating. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
BodybyFisher Posted March 9, 2007 Report Share Posted March 9, 2007 I just found info on the P1520 and in no place does it mention P0741. Here is info on P1520: Circuit Description This vehicle uses an electronic gear indicator display. There are four inputs which are switches to ground that each have a unique switch pattern. All four of these inputs are housed in the PNP switch assembly and operate together as the Transaxle Range Switch. The PCM uses the combination of the switch patterns to determine the gear selected by the driver. This information is then sent by serial data to the IPC for gear indicator display. This diagnostic test monitors the transaxle range switch for false outputs. The DTC will set if the transaxle range switch is indicating a switch pattern that the PCM does not recognize. Conditions for Running the DTC Tested continuously. DTCs P0502 or P0503 not set. Conditions for Setting the DTC Transaxle range switch indicating an illegal combination for 3.3 seconds Action Taken When the DTC Sets PCM will substitute park/neutral status from the Transaxle Fluid Pressure (TFP) switch for vehicle park/neutral status. The Malfunction Indicator Lamp (MIL) will not illuminate. The PCM will command a message to be displayed. The PCM may record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records. Conditions for Clearing the Message/DTC The PCM will turn the message OFF after one run and pass of the diagnostic test. A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test. A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. Use a scan tool to clear DTCs. Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. Diagnostic Aids Important Check shifter for normal freedom of movement. The gear select display will box all gear indications and flash on and off if an invalid or suspect gear position is received by the PCM. This will normally occur if the gear selector is not fully in a gear position. When a valid gear position is attained, the gear select display will immediately display the correct position. If the PRNDL on the IPC is flashing, this may be an indication that the shift cable and/or Transaxle Range Switch is out of adjustment. The modes (circuits) are displayed in order A/B/C/P. L indicates the circuit low (switched / shorted to ground). H indicates the circuit is high (open). If the DTC sets and the PRNDL on the IPC is flashing while driving or when the driver in not moving the gear selector lever, record the transaxle range switch input and compare the values to the table. For example, if the vehicle was operating in overdrive when the PRNDL on the IPC flashed and the input read High, Low, High, High, check for an intermittent open in circuit 773. Manipulate related wiring and connectors while observing the transaxle range switch input. If an intermittent is induced, the digit corresponding to the circuit will change. If wiring and connectors check out OK, substitute a known good transaxle range switch and recheck. Here is information on the P0741 code: http://caddyinfo.ipbhost.com/index.php?sho...33&hl=P0741 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...
RJSUS Posted March 10, 2007 Author Report Share Posted March 10, 2007 Thanks for the info......I'm just back to the old 741 which I'll live with...next concern to check on seems to be a chatter....do injectors make noise when they go south? I just found info on the P1520 and in no place does it mention P0741. Here is info on P1520: Circuit Description This vehicle uses an electronic gear indicator display. There are four inputs which are switches to ground that each have a unique switch pattern. All four of these inputs are housed in the PNP switch assembly and operate together as the Transaxle Range Switch. The PCM uses the combination of the switch patterns to determine the gear selected by the driver. This information is then sent by serial data to the IPC for gear indicator display. This diagnostic test monitors the transaxle range switch for false outputs. The DTC will set if the transaxle range switch is indicating a switch pattern that the PCM does not recognize. Conditions for Running the DTC Tested continuously. DTCs P0502 or P0503 not set. Conditions for Setting the DTC Transaxle range switch indicating an illegal combination for 3.3 seconds Action Taken When the DTC Sets PCM will substitute park/neutral status from the Transaxle Fluid Pressure (TFP) switch for vehicle park/neutral status. The Malfunction Indicator Lamp (MIL) will not illuminate. The PCM will command a message to be displayed. The PCM may record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records. Conditions for Clearing the Message/DTC The PCM will turn the message OFF after one run and pass of the diagnostic test. A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test. A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. Use a scan tool to clear DTCs. Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. Diagnostic Aids Important Check shifter for normal freedom of movement. The gear select display will box all gear indications and flash on and off if an invalid or suspect gear position is received by the PCM. This will normally occur if the gear selector is not fully in a gear position. When a valid gear position is attained, the gear select display will immediately display the correct position. If the PRNDL on the IPC is flashing, this may be an indication that the shift cable and/or Transaxle Range Switch is out of adjustment. The modes (circuits) are displayed in order A/B/C/P. L indicates the circuit low (switched / shorted to ground). H indicates the circuit is high (open). If the DTC sets and the PRNDL on the IPC is flashing while driving or when the driver in not moving the gear selector lever, record the transaxle range switch input and compare the values to the table. For example, if the vehicle was operating in overdrive when the PRNDL on the IPC flashed and the input read High, Low, High, High, check for an intermittent open in circuit 773. Manipulate related wiring and connectors while observing the transaxle range switch input. If an intermittent is induced, the digit corresponding to the circuit will change. If wiring and connectors check out OK, substitute a known good transaxle range switch and recheck. Here is information on the P0741 code: http://caddyinfo.ipbhost.com/index.php?sho...33&hl=P0741 Link to comment Share on other sites More sharing options...
BodybyFisher Posted March 10, 2007 Report Share Posted March 10, 2007 I don't think so, get a 3/4" hose say 3 feet long and put one end to your ear and the other try to find the noise...., that is a trick the guru used to quickly recommend.... it will help you localize the noise... obviously stay away from moving stuff... 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...
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