Here I was thinking my Cadillac troubles are over but ... A friend owns a '04 Deville DTS and was complaining to me about the SES light coming on and off randomly. He asked me to have a look since I went through so much trouble with my old Seville. During a test drive I didn't notice anything strange but a rough idle with slightly elevated rpm that totally goes away the warmer the engine got. The Deville also has abyssal gas mileage of below 13 MPG. After a couple of miles the SES light indeed came on and stayed on until we parked the car. 10 minutes later we got back in the car and drove the same route back with the light not coming on at any point in time.
Strangely, it is not throwing any code that can be read out with the internal code reader but two codes concerning the front seat adjustment motor. One remains of my old Seville was an external code reader that threw out the following:
Trouble Code: P0174
ABSLT TPS(%): 14.5
ENG SPEED(RPM): 2027
CALC LOAD(%): 50.2
MAF(gr/S): 29.45
MAP(KPa): 71.0
COOLANT(°C): 94
IAT(°C): 27
IGN ADV(°): 39.0
SECOND AIR: ATMOS
ST FTRM1(%): 8.6
ST FTRM2(%): 0.0
LT FTRM1(%): 21.1
LT FTRM2(%): 24.2
VEH SPEED(KPH): 78
FUEL SYS 1: CLSD
FUEL SYS 2: CLSD
After some quick research through this board, it could be a vacuum issue. We did a quick check of all apparent vacuum lines and the only one showing clear signs of degradation is the one circled yellow in the picture below. The rubber hose part is cracked by an inch (on the bottom) and the hole connection is very shaky and loose.
Unfortunately, I have no idea what that particular part is or what it's supposed to do - and therefore does not know whether this could be a/the cause for the SES light. I also read here on the boards that I should just get a can with some carb cleaner or so, carefully spray the vacuum lines, and listen for rpm changes to isolate any vacuum leaks. I'd like t do that but was unable to find a picture or diagram clearly marking all candidate spots. Is such a treasure hidden deeply somewhere?
EDIT: I didn't notice this at first with the code reader: P0174 is marked as "pending" while P0171 was "confirmed". Don't know how that translates into the H/C marks with the in-dash reader.
Strangely, it is not throwing any code that can be read out with the internal code reader but two codes concerning the front seat adjustment motor. One remains of my old Seville was an external code reader that threw out the following:
Trouble Code: P0174
ABSLT TPS(%): 14.5
ENG SPEED(RPM): 2027
CALC LOAD(%): 50.2
MAF(gr/S): 29.45
MAP(KPa): 71.0
COOLANT(°C): 94
IAT(°C): 27
IGN ADV(°): 39.0
SECOND AIR: ATMOS
ST FTRM1(%): 8.6
ST FTRM2(%): 0.0
LT FTRM1(%): 21.1
LT FTRM2(%): 24.2
VEH SPEED(KPH): 78
FUEL SYS 1: CLSD
FUEL SYS 2: CLSD
After some quick research through this board, it could be a vacuum issue. We did a quick check of all apparent vacuum lines and the only one showing clear signs of degradation is the one circled yellow in the picture below. The rubber hose part is cracked by an inch (on the bottom) and the hole connection is very shaky and loose.
Unfortunately, I have no idea what that particular part is or what it's supposed to do - and therefore does not know whether this could be a/the cause for the SES light. I also read here on the boards that I should just get a can with some carb cleaner or so, carefully spray the vacuum lines, and listen for rpm changes to isolate any vacuum leaks. I'd like t do that but was unable to find a picture or diagram clearly marking all candidate spots. Is such a treasure hidden deeply somewhere?
EDIT: I didn't notice this at first with the code reader: P0174 is marked as "pending" while P0171 was "confirmed". Don't know how that translates into the H/C marks with the in-dash reader.