I have a 2007 Lexus GS450H that has a new hybrid battery pack I installed back in August. It even has a new engine because the older one had gone bad. A few weeks ago, the car gave out a check hybrid system warning on the cluster and the arrows on the energy monitor disappeared and I could hear the hybrid cooling fan operating at maximum speed. 5 mins later, the VSC check light came on aswell. I scanned the codes and I found there were 2 fault codes: PA084 - Battery cooling fan 1 circuit low and P3177 - Transmission Oil pump motor coil temperature sensor circuit high.
I therefore, reconnected the connection to the oil pump motor located on the gearbox and the p3177 code disappeared. I put in a new cooling fan too but the pa084 code didn't go away. A few days later, the P3177 code came back. I've now got both the codes on my car. I've tried disconnecting the 12v battery for 5 mins and reconnecting but even that has not helped. What could be the issue?