tcu code 10?????

[H22A91CB7]

bump replaced switch b with working switch reset tcu still getting annoying code 10 flashing light

[James Matteu]

Retest

Have you repeated the full diagnostic? You need to perform the tests I described in your other thread.:


Again, how you test the switches is up to you. There are several ways to do this; you can pull the switches out and test them or can measure them in controlled situations while still in the car. I have some experience in this area, my V6 thread; I had a switch get stuck on my car, and feel that I have described below the easiest way to test them.

Be sure you use a Multimeter so that you can quantify your results. When you let us know what you find, give your results in Ohms.



Fuses:

First be sure that you have not blown fuses. Check Fuses: 39 and 19 in the Under-Hood Fuse/Relay block, and 7, 8, and 2 in the In-Car Fuse/Relay Block.


Relays:

Use a jumper wire and close the switch side of the Radiator Relay's connection. After the last tests, when the engine is warm, disconnecto the connector again to see if the relay is receiving voltage from the Cooling Fan Timer Unit.


Motor:

Verify the Radiator Fan has a good connection to ground, then use a probe and jumper wire to pull voltage right off the top of the fuse to the Radiator Fan's connector. With the Radiator Fan connected directly to Fuse 39 (15A), the fan should turn on immediately.


Switch and Sensor Preface:

There are two switches, one is the primary switch, the other is a back-up that switches on at a higher temperature should something go wrong and the first does not switch the cooling fan on. The first switch you pointed to in your video is Switch B and the one behind your distributor is Switch A. Switch A closes at 194 °F and Switch B closes at 226 °F. There is also a Sensor sitting behind Switch B, it controls the temperature needle on your gauge cluster. You may want to check this as well.


Sensor:

While the engine is cold, i.e. let the car sit over night; check the resistance across the sensor:

- between -4°F and 32°F, you should see between 5 and 20 ohms
- between 32°F and 104°F, you should see between 1 and 5 ohms

Then run the car for about 10 minutes or until you see the temperature needle rise. Check the resistance across the sensor:

- between 104°F and 176°F, you should see less than 1 ohm, but more than a tenth of an ohm
- over 176°F, you should see the ohms drop off to zero or float real close to it


Switches:

While the car is warm, see if one or both switches are open, i.e. no resistance between their contacts. While the car is warm, Switch A should be open. It is possible that the coolant is not hot enough to open both switches, see below. Verify both switches have good connections with ground.


TCU:

Helms Service Manual, Page 9-29:

Transmission Control Unit (TCU) Code 10's Possible Causes include:
1. Disconnected water temperature sensor coupler
2. Short or open in the water temperature sensor wire
3. Faulty water temperature sensor

After performing the tests above, you should be able to answer possible cause 1 or 3. Now look for an open or short in the wiring between the TCU and the Temperature Switches.





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