Is the IGCT relay built in to the integrated circuit in the fuse panel in the engine compartment? I am blowing the HEV 20 Amp fuse and am looking for the reason.
Yes. The Electrical Wiring Diagram (more info) shows that it is part of Unit C of the Engine Room Relay Block, also called the No. 1 Integration Relay. The Repair Manual has a diagram of the pinout and instructions for a bench test of the IGCT relay; see the procedure for Hybrid Control System diagnostic trouble code P3110/223. If you need a replacement, it’s part number is 82641-47020, list price $161.33. See parts catalog Figure 84-01, Switch & Relay & Computer, image 3, part name code 86241C.
Doubt its the relay. HEV fuse supports 2 circuits and both go the the Hybrid Vehicle ECU. One circuit is direct to that ecu as a stay alive on Pin 6 the other is post relay to that ECU pins 6 & 7. There a typo there with the pins I think but doesn't matter HEV fuse powers the ECU. Pull the fuse determine with your voltmeter which is the battery side then using the ohmmeter put the the probe on the load side of the fuse socket to ground and see if you have a dead short there. If so you have a dead shorted ECU. Do the same with the relay socket. Never seen a relay blow the fuse. Good luck.
OR the wiring harness is damaged and the wires providing 12VDC to the hybrid vehicle control ECU is shorted to body ground. I suggest the OP could disconnect the wiring harness connectors from the HV ECU and measure resistance from the appropriate pins to body ground to determine if that is an issue or not. This presupposes access to the electrical wiring diagram at techinfo.toyota.com Regarding the potential typo that Ed mentioned, I think that the first reference to pin 6 is part of connector B while the other reference to pins 6 and 7 is associated with connector C (since there are four wiring harness connectors in total.)
The pin numbers were on the ecu assy itself. If the wires are damaged that means its probably a salvage car.
I am blowing the HEV 20 Amp fuse and am looking for the reason. Install a 100 amp fuse. The reason will show up very "shortly". Not really serious, just a bit of electrical humor.....but... Although rare, there are times when that is necessary. When all else fails, sometimes there's no choice except to do a smoke test.
Pull the fuse and put a 12 volt bulb like a headlight bulb in its place. See how bright it is when car off. This is easy stuff with an ohmeter.
Have you had a chance to pull any DTCs from the OBD2 port? Here is the workup for DTC P3110/223 and DTC P3110/527 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Repair%20Manual/04pruisr/05/21bpm/3110223.pdf
