607 4HP20 auto trans Bridge converter coherence

[Franchute13]

Hello.!
I must say that the automatic box works excellent, does not jerk, it does not go into protected mode.
After changing the heat exchanger, I went for a spin to try the car.
Now I have an error which is as follows:
PERMANENT DEFECT. CONVERTER BRIDGE. COHERENCE.
Anyone know what you mean?
regards

[xantia_v6]

Is that fault description from the english language version of Lexia? I wonder if it means torque converter lock-up coherence?

[Franchute13]

Hello!
No, it is the translated Spanish version. It may not be a correct translation.
What does the error mean: torque converter lock-up coherence?
Greetings and thanks.

[xantia_v6]

Generally a "coherence" fault is one where the ECU is getting incompatible readings from different sensors, or it is commanding a solenoid to do something, but sensors show that it has not happened.

In this case it is likely that the ECU has commanded torque converter lock-up, but the speed sensors are reporting that the TC is still slipping. You should be able to confirm this by monitoring or recording the Lexia live data for the transmission while driving.

[Franchute13]

Hello!
First thanks for responding!
I have the Lexia / pp2000. What should I monitor to see that the TC is failing?
Thank you.

[xantia_v6]

You should be able to find parameters for engine speed and transmission input speed. The difference between those is the slip in the torque converter. When the TC is unlocked, the difference can be large, but when it is locked the difference should be less than 10%.
There is another parameter called (in English) "Status of the Torque Converter", which has 2 states and tells whether the TC is supposed to be locked or not.

You should also find that the recorded coherence fault code has some associated data, which may include the engine and transmission RPMs.

[Franchute13]

Hi.
Last weekend I tried the car. This time did not make a message error with the automatic transmission. Maybe it's a wiring problem or battery problem (it's already 2 years old).
The TC is as XANTIA_V6 says. A lot of difference in% when unlocked, very little when the TC is blocked. I understand that it works correctly.
Keep investigating.
regards