Volvo: DTC codes, efficiency test, volvo 850

Question
QUESTION: I have a 1994 volvo 850 turbo and i went and got the codes from the two small box located at behind the passenger headlight and these codes came about first is 435, second is 443 and lastly is 315. Can you please tell me what does this codes means. Thank you.

ANSWER: Hubadna,
Codes, 435 front HO2S slow responce time, 443 Catalytic converter efficiency signal too low, 315 EVAP system fault.

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QUESTION: Hi again just want to ask you what do I do with this problems. Do I replace the H20 sensor and the catalyctic converter? What about the EVAP system fault? Thank you.

Answer
Hubadna,
With the HO2S code I would replace both fornt and rear with factory not after market sensors. Do an intake injector cleaning with chemicals and see if the cat cleans up abd restores some efficiency. Test the evap system for leaks bad valve, broke hoses, bad evap solenoid. When all that is done see what the reading out of the tail pipe are. Will it pass emissions? Drive the car a couple of cycles see if the EVAP works.