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Just so we are all on the same page can I please have the year, make and model of Toyota you are working on please?
1. Since you said the check engine light does not come on, check the EFI fuses and the EFI main relay operation.
2. If the fuses are good and the EFI relay is being energized, check to see if the 5 volt reference is shorted going to the throttle position sensor, accelerator position sensor and the evaporative system canister assembly. 3. Check the power and grounds at the engine control module.
You said you have replaced the cooling fan module, what about the ECU, with a new one from Toyota?
After looking at the wiring diagram, the 5 volt ref. is a signal shared by multiple components and if one of those is creating an issue, it can do funny things to the rest of the circuit.
If you have a volt meter, you can check them that way, or just unplug them one at a time while the fans are running with the car off and see if the fans stop running after one of thoes items is unplugged. I know it seems odd, but trust me, there is a method to the madness.
let me know what happens!
I agree, this is tricky one. Thats why I took the question, I like odd ball issues like this. Give me some time today, to look over the wiring diagram and send you a copy of it, and we can walk through it, step by step and find this issue if that works for you.
SO what I am going to do, is have us start at the start of all this ,and unplug items one by one untill we can get the fans to turn off (with the key being in the on position)
bear with me a little as we walk through this some of it may seem like things you have tried, but I want to start from scratch, and get this figured out.
The first thing I want you to do, is turn the key to the on position so the fans will turn on. Then remove the IG1 relay, and let me know if that kills the fans or not.
Here is the diagram I am going off of.
Also, have you checked coolant temp. data with a scan tool to see what the temp. is reading from the sensor its self? If not, try that also just to make sure we dont have something there
Alright man. I ve done some digging this morning.I think I have isolated your issue down to the junction block inside the engine bay. I am going to be sending over some documents.With the EFI no 1 fuse pulled, you said the fans turned off. The EFI Relay is in the engine bay junction block. With the EFI fuse in, pull the relay, what happens?Pull the 30a RAD NO.3 fuse, after it is all back together and fans are still going. what happens (same junction block
Pull the Short pin out of the juntion block, same condtion, fan running key on. What happens?I think its going to be the connector on the back side of the fuse block that I am attaching with this info.In the diagram I attached with the connection highlighted in red and an arrow pointing to it, that is the junction block under the hood So if the HTR fuse is removed, yet the fans stay on, the next step in line is the junction block. If you pull the EFI NO.1 fuse in that junction block and the fans stop, we have it isolated to this junction block.
I really hope this makes sense and PLEASE feel free to ask any questions regarding my testing.
Awesome! Did you have any questions about what I am suggesting to try? Are you able to follow my thinking on why I am suspecting the junction box?
Awesome! let me know!
There has to be an issue with connector 2F or 2C in the junction box. Like we talked about before. Take the junction block apart and check thoes connectors that come underneath the junction box and check them for burning, chaffing, or corrrosion.
Sorry, I did not see your post at 9:58 when I wrote that. Disregard. let me check on your info.
The only thing that connects connectors 11852 and 11092 is the circuitry in the circuit board of the junction block.
I think you have a bad junction block buddy.The black and white wires should all be Ground.
EFI fuse has NOTHING to do with the cooling fans. the only thing that connects that to the cooling fan system is the junction block.
I just tried finding how the circuits run in the EWD, and no luck :(
I am sorry. I have been very busy. Ill dig into what you posted on the 6th, and get back with you tonight. Sorry about that!
Sorry, your post got lost and never showed up on my screen of questions and I had no idea how to get it back!Did you ever find anything out or do any more testing?