1999 Cadlillac Deville MIL back on

[Steve Ferraz]

I've reset it twice and the MIL light keeps coming back the next time I start the car, I'll try again to see if the same codes appear. But the "SERV STABILITY SYSTEM", Traction Control and ABS lights all stay on.

Oh and I forgot to mention one more thing, the steering now is a bit stiff. It wasn't like that before. Not a big deal but I now have to use a bit more strength than previously.

[Steve Ferraz]

Another thing I noticed that I forgot to mention is that when the engine is cold, the idle is a bit rough. But when it is warmed up, the idle is smooth.

[Steve Ferraz]

Ok, I reset the codes a few minutes ago and the MIL came right back.

Here's the updated list that includes if it is current © or history (H).

IPC B1552 H

SDM B1148 H

SDM B1169 H

SDM B1160 H

SDM B1163 H

SDM U1301 H

TCS U1301 H

TCS C1234 C

TCS C1235 C

TCS U1255 H

PZM B2470 H

PZM B2477 H

PZM U1301 H

IRC U1255 H

RFA U1000 H

RFA U1305 H

MMM U1300 H

MMM B2144 H

The P0113 disappeared but now a new code MMM B2144 appeared.

Also, I'm trying to find a vid of how to clean the idle air control valve and the throttle body for the '99 Cadillac Deville. What kind of cleaner would I need and where's the TB and IAC located? (Total newb at this but willing to learn.)

[Cadillac Jim]

You have network or electrical problems. The stiffer steering is probably because the speed-sensitive steering isn't working. I'll decipher the list of codes after work today.

[winterset]

Your C1234 and C1235 are causing your traction, ABS, etc. it is your right and left rear wheel sensors being disconnected. You'll need to check that they are plugged in, with no broken wires or connectors. For all the other codes, i would clean the battery terminals if you haven't done so.

[Steve Ferraz]

Gaah! The P0113 code came back so I guess the IAC will need cleaning to keep it from acting up? What cleaner do I use and where is the IAC located?

[Cadillac Jim]

CURRENT Codes:

TCS

C1234 Left Rear Wheel Speed Circuit Open or Shorted
C1235 Right Rear Wheel Speed Circuit Open or Shorted

HISTORY Codes:
IPC
B1552 Keep Alive Memory (KAM) Error

SDM
B1148 Passenger Side Air Bag System Malfunction
B1169 I don't have this one
B1159? Loss of Serial Data-Key Not Received
B1160 Loss of Serial Data - VIN Not Received
B1163 Loss of Serial Data-No Lamp Response
U1301 Class 2 Short to Battery

TCS
U1301 Class 2 Short to Battery
U1255 Class 2 Communication Malfunction (Serial Data Line Malfunction)

PZM
B2470 Daytime Running Lamps Fault
B2477 Reverse Lamp Relay Shorted to Ground
U1301 Class 2 Short to Battery

IRC
U1255 Class 2 Communication Malfunction (Serial Data Line Malfunction)

RFA
U1000 Class 2 Communication Malfunction
U1305 Class 2 Data Link Low or High

MMM
U1300 Class 2 Short to Ground
B2144 Left Front Mirror Vertical Position Sensor Circuit Low

Your rear wheel speed sensors are offline. That will turn on your TCS and ABS warning lights.

You have myriad network codes, including several that say the network line is shorted to battery. I would look first at the SDM module connector and wiring harness, then at the EBTCM connector and wiring harness I don't have a schematic for the 1999 Deville but I will look at my 2002 Deville schematic to try to help you figure it out if no one steps up with a schematic of the network for the 1999 Deville.

[Steve Ferraz]

B1159 not B1169. Derp.

I'll bring the car to the shop as soon as I can to get the sensors in the rear wheel reconnected.

I'd like to clean out the Throttle Body and IAC but I do not know the proper spray needed nor the location of said parts. Again, I'm a newbie at this.

What is SDM module connector and the EBTCM connector?

[Cadillac Jim]

The SDM module is the air bag module. The SDM acronym comes from Sensing and Diagnostic Module; it apparently was one of the first full-blown computer controls, allong with the PZM, the Platform Zone Module which is usually called the body control module in more recent years. In the 2002 FSM, it's "Under the rear of the center console, mounted to the console floor plan."

The 2002 FSM calls the brake/traction/stability module the EBCM, and says it is "Front left lower corner of the engine compartment, under the air cleaner housing." The brake manifold and TC pump/motor, called the brake pressure modulator valve (BPMV), is bolted to it and the EBCM and they funciton as an assembly. You can find the EBCM/BPMV by following the brake lines from the master cylinder or from the front wheels because *all* brake lines go to it.