Thread: Td5 Auto lock up and resetting adaptive values

If Lockup needs a minimum temp to function and my TCU is not reading engine temps above 55.5, then why is it locking up all?

If it is the TC I'm not going to change it. The economics don't work out.

Originally Posted by catch-22

If Lockup needs a minimum temp to function and my TCU is not reading engine temps above 55.5, then why is it locking up all?

If it is the TC I'm not going to change it. The economics don't work out.

Checked back on the thread and I think I know why the problem is doing your head in. It should have clicked when you mentioned the ECU upgrade thread

The Nanocom misreports Ambient Air Temp (AAT) sensors faults as a "Coolant Circuit Fault", and doesn't report live data from the AAT at all which makes it difficult to diagnose.

The other issue is that RAVE has no information about the function and impact of a faulty AAT sensor.

The AAT has a similar resistance curve to the Fuel Temp and Coolant sensors so, you can use that information to check that the readings are within ballpark.

From what I have been able to determine the AAT will fail to a default of maximum temperature, which will have the effect of reducing engine performance. This could be impacting the shift quality and lockup points.

cheers
Paul

Thanks Paul.

It does blow big black balls of smoke when started. I've read this can be related to the AAT.

I looked at the AAT yesterday and it was reading, when the engine was off and hadn't been started, the same temps as was outside. This was in the morning.

I also disconnected the AAT and there was no difference in the TCU engine temp reading. Did this with the MAF as well.

I'll read up on how to check one of these is functioning and see how we go.

Cheers.

I should have mentioned that when I disconnected the AAT a huge amount of errors appeared relating to all sorts of things. Very similar to what RoveV8 experienced. I cleared them all.

Originally Posted by catch-22

Thanks Paul.

It does blow big black balls of smoke when started. I've read this can be related to the AAT.

I looked at the AAT yesterday and it was reading, when the engine was off and hadn't been started, the same temps as was outside. This was in the morning.

I also disconnected the AAT and there was no difference in the TCU engine temp reading. Did this with the MAF as well.

I'll read up on how to check one of these is functioning and see how we go.

Cheers.

The Nanocom does not report Ambient Air Temperature. You are looking at Air Inlet Temperature (AIT) which is the temperature from the MAP/AIT sensor on the inlet manifold. They aren't the same and shouldn't be confused.

The TCU reports temperature from the ECT sensor relayed to it by the Td5 ECU. It is not effected by any other sensor.

The "logged high" fault suggest a short to supply in the wiring harness - possibly intermittent - rather that a faulty sensor.
All the temp sensors on the Td5 are NTC (negative temperature coefficient) so as the temperature increases the output voltage decreases. This means a high voltage at the ECU would be interpreted as very low temperature (anywhere down to -40°C) and timing and fuel injected adjusted to compensate. Black smoke is a possible outcome.

Depending on the exact effect of the problem the on the AAT readings this may also be altering the amount of power developed by the engine. The torque requested information from the Td5 ECU is also relayed to the TCU and if this is being altered by an intermittent fault in AAT sensor/loom it might explain variability in lockup behaviour.

cheers
Paul

Cheers Paul, this is all good stuff.

Seems I still have three avenues of investigation -

- AAT and it's loom
- TCU and the reasons it isn't reading the same engine temp figures as seen on the ECU
- TC lock up clutch itself

When it doesn't lock up, I'm not getting any faults on the ECU or the TCU. It just doesn't lock up. So a short is unlikely. However, values outside the normal conditions might not log faults....so that could be an issue.

I have the say the thing goes. Never has an issue with taking off or with climbing or towing or anything. With the performance ECU map it goes real well.

Without just starting to replace all these parts I'm at a loss as to additional troubleshooting I can do.....

- TCU and the reasons it isn't reading the same engine temp figures as seen on the ECU

I wouldn't rule out the gadget you have reading the info.....
Can someone else verify they get the same Engine temp readings in both modes using the same equip as you???

Good point Rover...I'll see if I can hassle someone about that.

Also, if solenoid 3 will only activate after all conditions are met for clutch lockup, then it, I'm pretty sure, can only be the TC. Again, today, I had solenoid 3 active and no lockup.