Transmission codes

patcal · Post by **patcal** » 23 May 2022, 10:09

Greetings,

This is on my 98 S70 GLT with 136k miles. I have had these 2 codes since I got the car almost 2 years ago. Car runs & shifts fine. The MIL light is not on. Mostly out of curiosity, wondering how I would go about testing this? I got this readout from 850 OBDII app. Vol-Fcr shows the same thing. TIA.

"AW 50-42 has 2 DTC: 35 18

AT-114: Mode Selector Switch, Signal too High [ie, short circuit to supply, driving mode selector module, or cluster fault feeding transmission fault light]

AT-223: Throttle Position Sensor (TPS) signal, signal too low"

Post by **scot850** » 23 May 2022, 10:27

Have you reset and see if they return?

From what you have written and the faults I am assuming an auto trans. 2 things jump to mind. One check all your grounds are good and remove the TCU and check the contacts are not oxidized. Clean contacts with a contact cleaner and a soft brush (like an old toothbrush) and then reseat it a couple of times. One of my cars had a bunch of trans errors but ran fine. I ended up taking it to a dealer and they cleaned the TCU with some Wurth branded contact cleaner and resat it a couple of times. Reset the codes and nothing came back after that.

Neil.

patcal · Post by **patcal** » 23 May 2022, 10:56

Neil,

Sorry I didn't specify, it is auto. I did clear the codes but they always come back. Corrosion is a possibility as I have found some in other connectors in the engine bay. Thanks for the help.

Post by **scot850** » 23 May 2022, 12:31

It is only help if it works!!

Neil.

Post by **misha** » 23 May 2022, 16:15

Do you have orange arrow light along with all other lights when key is in pos.II?

patcal · Post by **patcal** » 23 May 2022, 16:47

misha wrote: ↑23 May 2022, 16:15 Do you have orange arrow light along with all other lights when key is in pos.II?

All the lights light up as they are supposed to but they all go off after starting car.

Post by **misha** » 25 May 2022, 14:45

Since TCM malfunction light is working on bulb test when key is in pos.II...then i would check if S,E,W switches are fully engaging & disengaging,if they are stuck in some middle position,check contacts and clean if neccessary.

If that doesn't help...i would replace them.

About TPS sensor code...check it's connector under the throttle body.
Usually the oil from PCV system find it's way to TPS connector.
If that doesn't solve the problem...replace TPS...BUT ONLY with BOSCH unit with the same numbers.

Post by **hausmeister** » 07 Aug 2022, 13:36

I'll piggyback here; Since few days I have a flashing arrow while driving and code reads also
223: Throttle Position Sensor (TPS) signal, signal too low symptoms include high fuel consumption and weird shifting. Upon clearing the code everything is fine until it comes back (usually after driving for some time).

Now I already replaced the sensor with a new Bosch unit, thinking this was the issue, but it persists. I read about adjusting the throttle stop (to increase the voltage reading from the TPS?
But to me it is unclear if this is really the Issue for me. Volvo docs say 0.2 to 4.8 volt. I checked live data, it reads 0.47 to 4.2. The throttle is recognized correctly as closed/part/wot. Read somewhere else it should be 0.5v min.

I managed to get it to ~0.55v for minimum and might get a bit more by moving the tps a bit. But it seems to me there are 2 possibilities:
- The transm. computer is reading a differernt value (live data is from ecu) that is lower (?) or the specs are off and I need to adjust more?
- The problem is something different.

any input is appreciated

Should I try to measure the voltage directly at the TPS? Though the values I see in live data are plausible imo and change as expected. I did not change anything previous to the code on the car.
Already tried reseating AT comp and checked contacts which are perfect.

Post by **hausmeister** » 10 Aug 2022, 12:36

Today I measured the TPS on the pins that connect to the transmission computer (pin 20 on part B of the connector). It seems absolutely fine, 0.55v to 4.2v, and it increases very smooth with the throttle. Matches the live data from ECU. Measured ground, seems fine.
From this I conclude the TPS is working correctly, the voltage is high enough, and there is no wiring issue.

Is there anything else I can check that could cause the 223 TPS signal low error?

I have already ordered a trans ECU as it is not expensive and I kind of suspect that the electronics that measure the signal might have degraded. In any case I want to have a spare.

Post by **hausmeister** » 21 Aug 2022, 15:40

So, I installed a used replacement TCU. I was very skeptical, but I'm a bit optimistic now that it might solve my problem. I have driven ~130km since and so far no issues. It improved some characteristics:

- Fuel usage shown on computer has dropped by a lot. Not sure yet if this matches real fuel consumption
- shift points seem to be better / more logical now. Seems to shift a bit smoother?
- The car now responds to throttle modulation under ~wot, before it would kind of fall on its face (hard to describe) If I let off and got back on. Like it was undecided what to do.

I'll update once I have driven more, but since I notice these differences I kind of think the previous TCU really is partly faulty or degraded.