I know where the sensor 2 is but where is the bank 1 for my 1999 subaru forrester code PO 141 O2 sensor heater bank1 sensor 2?

If these codes only show after rain then the moisture is affecting the connections in the wires. Pull each connector apart and clean out with wd-40 or other water dispersant and ensure that the connections are water tight. Any dirt ,oil ,grease green gunk on the pins will cause a problem

Depending on the make model and year, code 141 is for a problem with the heater circuit for the O2 sensor bank one sensor two. Sensor two is after the catalytic converter.
The problem could be the sensor or the source of power for the heater circuit.

Forget to write it down?

Generic or Manufacturer?

There are 41 Generic O2 Codes

PO 131--bank 1 sensor 1
PO 137--bank1 sensor 2
PO 143--bank1 sensor 3
PO 151--bank2 sensor 1
PO 157--bank1 sensor2
PO 163--bank2 sensor 3

p0141 Chevrolet HO2S-12 (Bank 1 Sensor 2) Heater Circuit Malfunction oxygen sensor bank 1 sensor 2
p0108 Chevrolet
MAP Sensor Circuit High Input
i would do the o2 sensor first

P0136 = Oxygen Sensor Circuit Malfunction (Bank1, Sensor2)
P0141 = Oxygen Sensor Heater Circuit Malfunction (Bank1, Sensor2)

CHECK WIRING BEFORE REPLACING SENSORS

If 4 cylinder engine, there are only two O2 Sensors - Sensor 1 is on top, Sensor 2 is at the bottom

If 6 cylinder, there are four (4) O2 sensors (Bank1, Sensor2 is on the firewall side of this engine and is referred to as the 'DOWNSTREAM' sensor (the one AFTER the Catalytic Converter)

PO 134 = 02 SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 1 SENSOR1)
PO 153 =02 SENSOR CIRCUIT SLOW RESPONSE (BANK 2 SENSOR 1)
PO 154 =02 SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 2 SENSOR 1)
PO 155= 02 SENSOR HEATER CIRCUIT MALFUNCTION (BANK 2 SENSOR 1)
PO 171= SYSTEM TOO LEAN (BANK 1)
PO 174= SYSTEM TOO LEAN (BANK 2)
I WOULD SAY YOU HAVE FAULTY OXYGEN SENSORS CAUSING THE ENGINE TO RUN TOO LEAN REPLACE THEM AND YOU SHOULD BE BACK IN BUISNESS

po141, may be a bad o2 sensor, rear sensor after converter. the po 141 is low voltage to tps, try replacing the oyxgen sensor first and then reset the codes and drive if the po141 comes back then replace the tps,

P0141=O2 Sensor Heater Circuit Bank 1 Sensor 2
P0161=O2 Sensor Heater Circuit Bank 2 Sensor 2,
the 141 code is a problem with the heated O2 sensor on the drivers side exhaust after the converter,
the 161 code is the same except it is on that passenger side exhaust after the converter.

there are four O2 sensors,you need to check the sensor on the drivers side exhaust,the front O2 before the converter

Your oxygen sensor needs to be replaced.
The one behind (rear of )the converter on the exhaust system.
The code reads......P0136 (o2 sensor malfunction bank1 sensor 2)