Where to check vacuum hose: Code P0442
 

Hi, trying to get this CEL off on my girlfriends 2004 Scion XA with 160k miles on it. I was hoping someone could provide a picture of what hoses I need to check. I don't understand these cars, it's cramped and the front wheels make the car move. From doing a bit of reader here I suspect three months ago when the Toyota dealership did the oil change they disconnected a hose on accident.

Car drives ok, RPM rises / falls during idle. Dunno.

I'm getting codes -

P0420
P0446
P0442
P0441
C1241

most likely a faulty solenoid on the canister

First place to start off would be with the OBD C1241.

The letter C indicates the obd code is associated with Chassis Codes.
The number 1241 indicates low positive batery voltage.

The P0446 code can happen when too low amount of voltage is sent to the evap vent valve.

The P0441 code can happen when too low battery voltage is sent to the purge control valve.

The P0442 can happen if the C1241 code is causing codes P0441 and P0446

So, following the trail of codes in the most likely sequence of events, I would first clean the battery cables at ALL connections. This includes the battery attachment clamps, the negative CHASSIS ground wires. The positive battery cable end mounted on the starter. The negative battery cable end wherever it bolts onto the engine.......and all other negative ground cables. Clean the positive (constant 12v+) wire on the alternator.

Peel back some of the cable/wire insulation and see if there is corrosion inside the insulation. If there is corrosion, replace that ENTIRE cable.

Once the wire/cable attachment locations are cleaned, apply some dielectric grease to the connections and reassemble.

Clear the codes with a scanner and see what happens.


As for the P0420 code......I highly doubt if it is related to the C1241 code. You either have a bad catalytic converter or you have a bad B1S2 sensor......however, since there is no code P0141 indicating a bad B1S2 sensor, the problem is more likely that you have a bad catalytic converter.

Catalytic converters are not normally a part that wears out IF the driver CONSISTENTLY uses QUALITY gas, quality oils and performs routine "tune ups" utilizing OEM parts.

My grandmother has a Cadillac Escalade with over 400,000 miles on the same set of original GM catalytic converters. Her truck has only been serviced at Cadillac dealerships using only GM factory replacement parts. She only uses the best gas with the highest octane rating from Chevron.....in contrast, my brother has a Chevy Avalanche (basically the same GM vehicles with the same powertrain), he does all his own tune ups and stuff. Uses the correct octane rated fuel from the cheapest gas pump he can find (usually Valero gas stations).........he's already burned thru the factory set of catalytic converters with only 110,000 miles on them. My point is: If a cat converter goes bad, its because the vehicle has had poor maintenance in the past and has been fed low quality gas all it's life.

PS: Octane rating has nothing to do with how "good" a fuel is.