"Freeze Mode", aka how to kill S1a

Hi Ed, sorry for the late reply.

The relevant parameter to look for is CAT temp, B1S1. If the temp is below about 230° , it will trigger S1a and the use of the battery.

I've read your testing, let me speak with the guy in charge and i'll let you know.
Thanks for your testing anyway!

 

Carefully thinking, you're all-way-round test let me think that the trick could be the excessive difference btw the resistance of the sensors. What resistence you did applied to actually decrease the resistance to check the fan? It would be possible that some difference btw the sensors is tolerated, an excessive one, throw the code....
I've sent a message to the guy that will make the spoof for me, i'll be back on it.

 

There are 2 CAT sensor and one is closer to the engine and so it will read an higher temp, no worry, whatever is your reference it will be OK. Anyway, i do use Torque PRO on smartphone.
We should check form the diagram what false temp should equate your 15kohm but i would say the difference btw the 12° read by the other sensors should be less than the difference btw the spoofing for the "Freeze mode"... i'll double check it.

To know what is the best action we have first evaluate the equivalent temp differential in the 2 modes you tested, i would not make wild guesses...

 

Lucky accident

 

Wait a sec: did you said your resistance was 50 OHM in series?

From the graph, at 12°, the sensor have about 25 Kohm resistance. To spoof it , we should have a total about 50 Kohm. So the extra resistance to spoof at about -10° should be about 25/30 Kohm which is quite far away from 50 OHM...

 

sorry Ed, explain yourself a little better , and double check the use of the prefix "kilo" (or lack of it) in the msg

 

edit: double post

 

As i suspected earlier, the quote from Toyota of "abnormal" values of temp giving a DTC confirms that you first test introduced by far a too high resistance. And i still don't know which value you came up with in that test, but, whatever...

That's right, that was the way to go, rotating the variable resistor value till the reading of the proper figure on Torque.
You hacked the sensor nr1 but the Nr.2 seems to be preferable. In my Auris sensor nr.2 shows the max temp, but in the Prius could be different because we have the battery under the rear seat and not in the trunk.

Having said that, i would not lose my mind of the different trigger point depending on the battery temp because what you said seems to be inconsistent.
Rotate the resistor until a -20° is shown in Torque and you will allow for summer temperatures. And check it.

The battery temp that triggers the fan is about 35° at the hottest sensor: this is also why i dont' think is necessary to spoof all the sensor, the system is setup to evaluate the worst case.

Please, if you can, tell me the value of the resistor at the experiment of -9° trigger point. And don't mess up ohm with kohm

Also, have you done a street test to evaluate the difference (FE and SOC) btw a normal S1 and the spoof?

PS: For the time beeing, i would suggest to restore the original conditions upon testing btw 1 minute and 2 minutes max from ICE start.

 

That's the correct procedure jacek, apart that mid HSI is quite battery consuming, but it's only viable if you don't have multiple stops on short trips and/or you don't need some substantial acceleration.
In the multiple stops scenario, is mostly the insufficient cat temp to trigger multiple S1, rather than coolant temp.
For just 2 S1a in a day, i would not even use a block heather, this hack is for frequent S1a fliers


Kudos to FORD FUSION for having introduced the S1a skipping on the HSD (the "B" trick), and the Active Grille Shutter. And the recent software update that reduce from 65° to 55° the passage on S3 .....
FORD-TOYOTA, 3 to 0 .....