P0430 and U1900

oliver · #1 12-10-2018, 12:15 PM

2007 Ranger with ~60k miles

This weekend, a couple of things happened:
1) tons and tons of rain and and big puddle of water in the passenger footwell

2) Check-Engine-Light came on and my OBDII reader said:
i) P0430 Catalyst system efficiency below threshold (left cylinder bank)
ii) U1900 CAN communication bus fault

Is it likely that the U1900 is also causing the P0430? Should I be looking for a disconnected wire (or perhaps one chewed through by a rodent)? I haven't seen a rodent but I see what looked like four or five mouse poops under the air filter. Not sure how long they'd been there.

For the puddle, it doesn't look like the door seals are bad and the inside of the door seems dry so I think it's coming through the engine (via those grills by the windshield?) Any chance this could have shorted something out? I'm thinking it's unlikely but I don't like coincidences

It's been too wet to get a good look so I'm trying to narrow down my scope here

djfllmn · #2 12-10-2018, 12:25 PM

look at the fuse box in the right side kick panel, see if that got wet. I doubt they are related

Dirtman · #3 12-10-2018, 12:28 PM

U1900 is a bitch of a code because there's no details of exactly what module is not communicating. However it is unlikely in my opinion to be related to the p0430 which is usually a bad cat or downstream o2 sensor. But checking for a shorted wire on the downstream o2 sensor harness would be first on the things to check.

As for the u1900... check all the fuses for the abs, instrument cluster, pcm, gem (dunno if 07 still had a gem or an sjb), etc. Check grounds, check for broken wires.

djfllmn · #4 12-10-2018, 12:39 PM

Quote:

Originally Posted by Dirtman

U1900 is a bitch of a code because there's no details of exactly what module is not communicating. However it is unlikely in my opinion to be related to the p0430 which is usually a bad cat or downstream o2 sensor. But checking for a shorted wire on the downstream o2 sensor harness would be first on the things to check.

As for the u1900... check all the fuses for the abs, instrument cluster, pcm, gem (dunno if 07 still had a gem or an sjb), etc. Check grounds, check for broken wires.

SJB. Also contains the fuses. So if that sucker got wet..yikes

oliver · #5 12-10-2018, 01:37 PM

Thanks all... I did pull that fuse box cover off in the kick panel and it seemed dry. Even saw a little cobweb in there. Hopefully I can get a better look tomorrow

djfllmn · #6 12-10-2018, 01:41 PM

Quote:

Originally Posted by oliver

Thanks all... I did pull that fuse box cover off in the kick panel and it seemed dry. Even saw a little cobweb in there. Hopefully I can get a better look tomorrow

pull the box out completely, check for water intrusion in the backside of the connector

oliver · #7 12-16-2018, 05:16 PM

Sorry for the lack of updates... After everything dried out the CEL is not longer lit and I couldn't easily see how to remove that SJB. I'd rather not touch it again until I have to but I have a starting point next time it happens.

Thanks to everyone for the advice