jhall Posted July 13, 2005 Report Share Posted July 13, 2005 Hi all, Need some help! I just finished reinstalling the engine in my '97 Deville and have started driving it longer distances. Everything has been running perfect, but I did have a "traction light" come on and these codes were set were set after driving about 60 miles. right near this time I hit a bump in the road and the cruise control kicked out and wouldn't engage anymore: PCM 1571 - "Traction Control PWM CKT No frequency" A pulse signal not received on desired torque circuit for 3 seconds. TCS 1277 - Requested Torque signal Circuit Malfunction" There is an open or short in the requested torques line between the ABS module and PCM or there is a TCS communication malfunction detected by the PCM. I suspected the large connector on the ABS/traction control module. I pulled the connector and reinserted, cleared the codes and everything worked OK (no more codes have been set at this point). I am now having problems with the cruise control. It failed to work again today. I did the electrical troubleshooting according to the manual and found that one of the wires that sends the vehicle speed signal to the cruise control is apparently not working. I was not getting a voltage swing as I rotated the front wheels (used a digital voltmeter) The manual says this is circuit 817 (vehicle speed sensor) and to check for an open in the wire or a short to ground (no ground shorts were found during the check). Note - I replaced the speed sensor in the transmission with a new one during the rebuild and rechecked the connector today. It looks OK and the speedometer and transmission work just fine. I did a circuit trace back inside the car on the circuit 817 wire through the main connector at the firewall and it looks OK. The cruise control switch also appears to be OK since the proper voltages showed up as I pressed the "on/off" and "set" switches during the check. I did not check the switch on the brake yet. I pulled the large connector on the ABS unit and checked the contacts for damage. I replaced the connector and the cruise control worked for one test drive. I had to jack the front of the car up to check the front end and now the cruise control does not work again!! I can't find anything in the manual that shows that the ABS connector is linked to the cruise control module, but it seems like something is related. Can anyone provide some ideas? Everything on the car works beautifully and this one non-functioning item will drive me crazy if I don't fix it. Link to comment Share on other sites More sharing options...
jhall Posted July 13, 2005 Author Report Share Posted July 13, 2005 bbobynski, Yeah, thanks for the response. I tried that on the last test drive - no luck. I have a fixation on the ABS module connector since messing with the connector seems to change the situation. The cruise was working when I took the engine out, so it seems logical that the connector is suspect. Oh, by the way, I had a PO153 code from a bad O2 sensor on the front manifold after I put the engine back in. I replaced it and cleared the code. The car needed inspection, so it took it to the local shop for an emissions test. The car indicated that a number of sensors (e.g. O2, catalytic converter, etc) and other emission-related devices were "not ready". They told me to drive it a while (150 miles or so) and come back. I'm not sure if the "not ready" response might be a problem with the car computer. How many drive cycles are needed to be able to pull emissions data? I'll keep plugging away until I find it. It drives me nuts that things like this happen after a major job and one or two convenience items go south. Link to comment Share on other sites More sharing options...
jhall Posted July 14, 2005 Author Report Share Posted July 14, 2005 Hi guys, Got in the car this morning and the dang cruise was working! BUT, as soon as the engine got about 197 degrees, the cruise quit working and did not engage for the rest of the day . I checked the schematics and found a relationship with the ABS and cruise control systems - mainly the switch on the brake pedal, but also a PWM signal that feeds to the cruise module. I have doubts that the switch went bad from just letting the car sit for 8 months while I repaired the engine, but I'll check it anyway. I'm guessing that the large connector on the ABS module is having a connection problem at the PWM pin. More to follow. Link to comment Share on other sites More sharing options...
jhall Posted July 15, 2005 Author Report Share Posted July 15, 2005 OK, one more update, The cruise control ('97 Deville) worked this morning until - you guessed it - the engine got around 197 deg F and then it would not engage again. I brought it home this afternoon and let it cool off, pulled the large connector off the ABS module to clean the contacts again and also checked the switch on the brake pedal with an ohmmeter(everthing OK here). After this, the cruise worked until the engine heated up. This is really perplexing, but for kicks I'm going to try moving the connector after the engine heats up to see if I can make it work (sort of tough to do - it's pretty hot in that area). Based on the schematics, and since I'm not getting any codes, I suspect the pulse width modulation (PWM) signal from the speed sensor is not reaching the cruise control via the ABS module connector due to a bad connection. Anyone seen this type of problem before? Link to comment Share on other sites More sharing options...
JIMDTS Posted July 15, 2005 Report Share Posted July 15, 2005 Some of these elec. problems are a pain to pin point It almost sounds a connection problem heat will change resistance values at the connections I don't have the manuals for the 97 oldest i have is from 98 These steps may work if it's the same system I'm not sure if the 98 is the same as a 97 model yr. You can just use your multi meter to check the system Good Luck Jim Document ID # 510179 1998 Cadillac DeVille -------------------------------------------------------------------------------- Cruise Control Inoperative Step Action Value(s) Yes No 1 Did you perform the Cruise Control System Check? -- Go to Step 2 Go to Cruise Control System Check 2 Turn the CRUISE switch to OFF. Disconnect the cruise control module connector. Turn the ignition switch to RUN. Connect a J 39200 digital multimeter (DMM) between terminal F of the cruise control module connector and ground. Is the measured voltage in the specified range? 10-15V Go to Step 4 Go to Step 3 3 Repair the open in CKT 339 (PNK). Is the repair complete? -- Go to Step 31 -- 4 Connect a J 39200 DMM between terminal F and terminal E of the cruise control module connector. Is the measured voltage in the specified range? 10-15V Go to Step 6 Go to Step 5 5 Repair the open in CKT 451 (BLK/WHT). Is the repair complete? -- Go to Step 31 -- 6 Connect a J 39200 DMM between terminal E1 of connector C202 and ground. Is the measured voltage in the specified range? 10-15V Go to Step 8 Go to Step 7 7 Repair the open in CKT 1039 (PNK). Is the repair complete? -- Go to Step 31 -- 8 Turn the CRUISE switch to ON. Connect a J 39200 DMM between terminal E2 of connector C202 and ground. Is the measured voltage in the specified range? 10-15V Go to Step 10 Go to Step 9 9 Inspect the multifunction lever connector for poor terminal contact. If the contact is OK, replace the multifunction lever. Refer to Turn Signal and Multifunction Switch Assembly - Disassemble - Off Vehicle and Turn Signal and Multifunction Switch Assembly - Assemble - Off Vehicle in Steering Wheel and Column - Tilt. Is the repair complete? -- Go to Step 31 -- 10 Connect a J 39200 DMM between terminal A of the cruise control module connector and ground. Is the measured voltage in the specified range? 10-15V Go to Step 12 Go to Step 11 11 Repair the short to ground or open in CKT 397 (GRY). Is the repair complete? -- Go to Step 31 -- 12 Connect a J 39200 DMM between terminal E3 of the connector C202 and ground. Press and hold the SET button. Is the measured voltage in the specified range? 10-15V Go to Step 13 Go to Step 9 13 Connect a J 39200 DMM between terminal B of the cruise control module connector and ground. Press and hold the SET button. Is the measured voltage in the specified range? 10-15V Go to Step 15 Go to Step 14 14 Repair the short to ground or open in CKT 84 (DK BLU). Is the repair complete? -- Go to Step 31 -- 15 Connect a J 39200 DMM between terminal G of the cruise control module connector and ground. Is the measured voltage above the specified value? 0.5V Go to Step 16 Go to Step 17 16 Repair CKT 20 (LT BLU) for the short to battery positive voltage (B+). Is the repair complete? -- Go to Step 31 -- 17 Connect a J 39200 DMM between terminal D of the cruise control module connector and ground. Press the brake pedal, then release the pedal. Is the measured voltage less than 0.5 volts with the pedal pressed and in the specified range with the pedal released? 10-15V Go to Step 23 Go to Step 18 18 Turn the ignition switch to OFF. Disconnect the ABS/TCC switch connector. Connect a J 39200 DMM between ABS/TCC switch connector terminal A and ground. Turn the ignition switch to RUN. Is the measured voltage in the specified range? 10-15V Go to Step 20 Go to Step 19 19 Repair short to ground or open in CKT 1039 (PNK). Is the repair complete? -- Go to Step 31 -- 20 Turn the ignition switch to OFF. Connect a fused jumper across ABS/TCC switch connector terminals A and B. Connect a J 39200 DMM between cruise control module connector terminal D and ground. Turn the ignition switch to RUN. Is the measured voltage within the specified range? 10-15V Go to Step 22 Go to Step 21 21 Repair the open, short to ground, or short to battery positive voltage (B+) in CKT 420 (PPL). Is the repair complete? -- Go to Step 31 -- 22 Inspect the ABS/TCC switch connector for poor terminal contact. If the contact is OK, replace the ABS/TCC switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Is the repair complete? -- Go to Step 31 -- 23 Set the park brake. Raise the drive wheels. Using a J 39200 DMM, measure the voltage between cruise control module connector terminal K and ground. While observing the display of the DMM, rotate the drive wheels by hand. Does the voltage vary? -- Go to Step 25 Go to Step 24 24 Repair the open in CKT 817 (DK GRN/WHT). Is the repair complete? -- Go to Step 31 -- 25 Turn the ignition switch to OFF. Reconnect the cruise control module. Disconnect the powertrain control module (PCM) connector C1. Connect a J 39200 DMM from PCM connector C1 terminal 26 to ground. Turn the ignition switch to RUN. Is the measured voltage within the specified range? 10-15V Go to Step 28 Go to Step 26 26 Test CKT 83 (DK GRN) for an open or short to ground. Is the circuit OK? -- Go to Step 29 Go to Step 27 27 Repair open or short to ground in CKT 83 (DK GRN). Is the repair complete? -- Go to Step 31 -- 28 Turn the ignition switch to OFF. Reconnect the PCM connector C1. Disconnect the cruise control module connector. Turn the ignition switch to RUN. Using the Scan Tool , clear all of the DTCs. Using the Scan Tool , select PCM, Special Functions, Engine Output Controls. Select Cruise Inhibit and command the PCM to turn cruise inhibit off. Using a J 39200 DMM, measure the voltage from the cruise control module connector terminal H to ground. Is the measured voltage within the specified range with Cruise Inhibit off (NO), and less than 0.5 volts with Cruise Inhibit on (YES)? 10-15V Go to Step 30 Go to Step 29 29 Inspect the cruise control module connector for poor terminal contact. If the contact is OK, replace the cruise control module. Refer to Cruise Control Module Replacement . Is the repair complete? -- Go to Step 31 -- 30 Diagnose the powertrain control module (PCM). Refer to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.0L, 4.6L. Is the repair complete? -- Go to Step 31 -- 31 Ensure that any components removed during diagnosis are installed in place. Ensure that all of the connectors are connected. Repeat the system check. Refer to Cruise Control System Check . Is the system check complete? -- System OK -- Link to comment Share on other sites More sharing options...
MAC Posted July 15, 2005 Report Share Posted July 15, 2005 Just reconnect the vacuum hose to the Servo Unit? Link to comment Share on other sites More sharing options...
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