: P0122 on 96 Fleetwood



95BRMW
05-29-13, 10:44 PM
My Fleetwood decided to start acting up over the weekend on my way home on a 100 mile trip. While cruising on the highway there was some light bucking felt followed by the Traction light coming on. A few minutes later the CEL joined it. I got off the highway and noticed right away that the shift points were way off and it was running bad. I ran the codes and got P0122 which is something with the TPS circuit. I cleared the codes and it drove fine for about a mile then it happened again. I drove it home like this.
Today I went out and swapped the sensor with a known good one from my parts engine, cleared the code and it seemed fine. Once it warmed up (about a mile of driving) the Traction light came on followed by the CEL again. I checked the wiring to the TPS with a meter and everything seems in spec, I get 5v on one wire, good ground on the other and a nice smooth variable voltage between .6v and 4.6v. I compared these to my Roadmaster and they match. I went and pulled the PCM out and checked the continuity between the sensor wires and the PCM, wiggled the conenctors and the whole harness around and everything stays solid. I tried a spare PCM I had and got the same problem.
With my meter and scanner hooked up, I went for a ride. I got back home and see the engine is running fast in Park and my scanner shows 22% throttle. I check my meter and it still shows .6v. I shut it off, restart it and the car idles normally, scanner shows 0%.
According to Alldata part of the diagnostics is to disconnect the EBTCM and check the readings. Is that part of the ABS pump under the hood? I can't find any info on this part.

I'm at a loss here, the wiring seems fine, its not the sensor or the PCM. Anyone else see this before?

jayoldschool
05-29-13, 11:50 PM
disconnect the EBTCM

T raction
C ontrol
M odule

Perhaps?

MoistCabbage
05-29-13, 11:57 PM
Yup.

Electronic Brake and Traction Control Module

95BRMW
05-30-13, 12:14 AM
So this is part of the ABS system by the steering gear? I tried unplugging that and the cruise/traction module on the fender.

turbojimmy
05-30-13, 11:17 AM
Yes, the EBTCM is by the steering gear.

95BRMW
05-30-13, 07:29 PM
Disconnected the ebtcm and get the same result, harsh shifts and the cel comes back after a short ride. Once again it's fine initially. Anyone have access to an fsm?

MoistCabbage
05-30-13, 08:10 PM
The EBTCM has nothing to do with shifting or the CEL. Alldata says unplug the EBTCM to diagnose the TPS?

95BRMW
05-30-13, 08:37 PM
The TPS wiring does connect to the Traction module on the D-body, I guess it wants to isolate that a a cause.

turbojimmy
05-30-13, 10:49 PM
FSM says that when the P0122 Sets, you get this:

- MIL light
- PCM uses a default TP sensor value
- No TCC lockup
- High transmission line pressure
- Fixed shift points, hard shifts and no 4th gear in hot mode

So that explains the behavior you're experiencing.

The diagnostics are basically to check the wiring and check for 4.7V reference voltage at the TPS. If it's intermittent, it says to perform the DTC P1122 diagnostic procedure to isolate the cause of the fault. If replacing the TPS doesn't work, they say to replace the PCM.

The P1122 diagnostic table says that if a P0122 is present then there's a hard failure of the TPS circuitry. The P1122 failure indicates an intermittent drop out of the TPS and will not illuminate the MIL. Like the P0122, the diagnostic table basically has you search for a bad connector or wire somewhere. Check the connectors carefully, make sure they're clean and look for rubbed through wire insulation.

95BRMW
05-30-13, 11:23 PM
I did all of that already unfortunately. I have a bunch of cut connectors around, I think I may just make a harness with them and connect the TPS directly to the PCM and see if anything happens there.

95BRMW
06-01-13, 01:12 AM
update: I bypassed the tps circuit and wired it directly to the pcm. that got rid of the problem, but now theres others. Both fans are on at all times when the engine is running, but there's no codes or a CEL. the car drives fine otherwise. the other issue is the ac compressor won't engage. there's plenty of refridgerant but the compressor won't get power. this started yesterday, the primary fan would come on when I turned the ac on, but with both being on that doesnt matter anymore. I'm guessing I have a short or something somewhere.

turbojimmy
06-03-13, 05:30 PM
Do you have any other codes? Some errors will run the fans continuously and disable the A/C. Not all errors light the MIL.

95BRMW
06-06-13, 11:42 AM
Problem solved! The issue was the wires for the AC pressure switch down by the compressor got pinched against the refridgerant line in the plastic clip and finally wore through. These wires share the same circuit as the TPS and as a result took out both systems. So, a little electrical tape and some new wire loom took care of this. Thanks for the help guys!

turbojimmy
06-06-13, 12:55 PM
Sweet! It's frustrating while you're troubleshooting, but so satisfying when you find and fix it!

Cadillacboy
06-06-13, 03:35 PM
Great news. I am happy you got it sorted out