OBD-II Drive Cycle Problem Topic is solved

bluewagon · Post by **bluewagon** » 19 Oct 2024, 20:50

1996 Volvo 850 GLT Wagon with Manual transmission.

I have a problem with the drive cycles. None of the sensors want to go into the ready position after installing new Bosch O2 sensors and 3 complete multi-step cycles. (This is quite confusing, because prior to replacing the O2 sensors most of the other sensors went into the ready position.)

Does anybody have any ideas?

Thank You,

(pic of OBD-II display)

Post by **jreed** » 20 Oct 2024, 06:54

Just checking that you had the AC off and did not exceed 60mph per the advice below:
viewtopic.php?t=14429&start=10

bluewagon · Post by **bluewagon** » 20 Oct 2024, 17:57

Thank you for your reply.

a/c was off, and I did not exceed 60 mph during the drive.

I did notice something else. Using the bluetooth connection on the OBD-II reader unit I discovered a stored code PO422 (bad catalytic converter). Oddly, I do not have a check engine light along with that code. (Yes, the check engine light comes on when the key is in the start position before the car starts so it is not burned out.) Could this stored code be related to the sensors not going into a ready status?

Post by **jreed** » 21 Oct 2024, 05:36

That's puzzling that the P0422 is stored. Did you reset the codes after replacing the oxygen sensors?

xanthefin · Post by **xanthefin** » 21 Oct 2024, 06:59

I want just shortly share. Not all codes trigger MIL/Check Engine light. And Yes most likely fault code is related.

Picture got lost in bit space.

bluewagon · Post by **bluewagon** » 21 Oct 2024, 20:04

jreed wrote: ↑21 Oct 2024, 05:36 That's puzzling that the P0422 is stored. Did you reset the codes after replacing the oxygen sensors?

Thank you,

This Odd-yssey began with the failure of the Secondary Air Pump. That threw the CEL. After it was replaced the mechanic reset the SEL. I could not get all of the sensors to reset so I replaced the fore and aft non-Bosch O2 sensors with new Bosch units. After I replaced the O2 sensors I cleared the codes.

My OBD-II reader has a bluetooth connection feature. I just set it up and found the stored P0422 code.

bluewagon · Post by **bluewagon** » 21 Oct 2024, 20:06

xanthefin wrote: ↑21 Oct 2024, 06:59 I want just shortly share. Not all codes trigger MIL/Check Engine light. And Yes most likely fault code is related.

Picture got lost in bit space.

Thank You,