1997 850GLT Failed Emmission codes

mta58 · Post by **mta58** » 04 Feb 2015, 03:25

I just failed emissions. Codes were PO 116, PO 442 and PO 445. I've checked this forum for similar posts.

I just replaced the Alternator about 1 month ago and everything seemed fine at that time. The battery kept going dead.

Are these codes related to that event and if so, what do I need to do to correct the code readings ?

Thanks in advance for any help.

Post by **jreed** » 04 Feb 2015, 05:17

Welcome to the site!

For the P0116 code, it could be due to a failed engine coolant temperature sensor. This is not an expensive part to replace. More info here:
https://www.matthewsvolvosite.com/forums ... hp?t=10667

The P0442 and P0445 codes are for the evaporative emissions control system. Lots of 850's (if not all) have had these codes come up. Generally there are cracked vacuum lines, a worn out gas tank cap seal, or failed purge valve, among many many other potential causes, More info here:
https://www.matthewsvolvosite.com/forums ... =1&t=63069

mta58 · Post by **mta58** » 15 Feb 2015, 20:17

Another update to Emissions test: My 850 GLT on board computer now refuses to connect with the Emissions Testing computer. I have tried at 5 times allowing for reset time between each test. Does anyone have an idea what can be causing this ?? The local used parts guys want me to disconnect my computer for 10 - 15 minutes but I have no idea how to safely do this. And of course, time is now short.
I am wondering if something happened to it when my alternator was replaced.
Thanks in advance.

Post by **jreed** » 16 Feb 2015, 05:13

I haven't experienced this problem but a couple of ideas come to mind that may be of use.
1. Do you have an OBDII code reader? If so, does it successfully connect to the car's computer? If it can connect that is a good sign that your car's computer and OBDII connector are OK.
2. Regarding disconnecting, the mechanic may be referring to disconnecting the battery cable from the battery for 15 minutes. This will have the effect of resetting the car's computer.
It's hard to say if the alternator replacement might have been associated with the codes you are getting. On the face of it, it seems unlikely but on the other hand the engine coolant temperature sensor and it's sometimes brittle connector are right next to the alternator and could have been affected during the change. Also the evaporative emissions control codes are often due to damaged or disconnected vacuum lines. There is a vacuum line that is supposed to connect to the intake manifold near the alternator... you might inspect this one and see if it's still intact, in good shape and connected.