View Full Version : Getting codes P0452 and P0449 on my 07 Escalade

11-07-11, 03:55 PM
2 weeks ago while driving the DTC light came on. I had just filled up so I figured the guy didn't tighten the cap and that's what caused it. After getting home and hooking up my scanner I checked the codes and saw P0452 and P0449. I cleared the codes and sure enough they came right back on before getting down the block. First I tried changing the gas cap which didn't do anything. Then I changed the vent solenoid. Still have the DTC's. Then I changed the purge and canister. The DTC's still wouldn't go away. Finally I changed the fuel tank pressure sensor (P0452) and I still have the damn codes. I borrowed a tech 2 from a buddy and it looks like the the fuel tank pressure sensor isn't getting any voltage which is making me think it's a wiring problem. Does anyone have any insight on this? Does anyone happend to have a wiring schematic for the evap system and the fuel tank pressure sensor? The truck is running fine (still gets 19.8 mpg avg on a 100 mile trip at 75 mph) but this light is killing me. I'm thinking somethings up with the wiring in the back of the truck since the pressure sensor and the vent solenoid aren't far from each other. Any help is appreciated. I really don't want to bring this in for service since it's not a warranty item and I can only imagine what it'll cost to diagnose a wiring issue.

11-09-11, 09:49 AM
Anyone? Does anyone here work for a GM dealer that can get a pic of the wiring diagram for the Vent Solenoid and Fuel Tank Pressure Sensor?

Cadillac Cust Svc
11-09-11, 12:34 PM
If you do not get the diagram in this forum you can check helminc.com. let me know if you find what you are looking for.
Cadillac Customer Service

11-09-11, 03:20 PM
Thanks for the link Breanne. I checked it out and unfortunately, they don't have the wiring diagram for my truck.

11-09-11, 05:53 PM
my work browser wont allow me to upload the schematic. If you have a 4wd then check the wiring for contact on your driveshaft that goes from the tcase to the front diff

11-10-11, 12:34 AM
my work browser wont allow me to upload the schematic. If you have a 4wd then check the wiring for contact on your driveshaft that goes from the tcase to the front diff

Thanks 99SSConv, I'll check it out. Also, great username...I also have a 98SSconv.

11-10-11, 09:35 PM

11-10-11, 09:38 PM
was the harness rubbed through on the front driveshaft?

11-14-11, 01:48 AM
Hey bud, thanks for the schematic. The harness isn't rubbed through so it looks like I'll be chasing some wires.

11-17-11, 02:54 AM
Before you chase wires, try re-seating your engine compartment fuze box assembly by lifting the grey handles until the center section can be lifted from the outer holder. Then push it back down and re-seat it by lowering the grey arms until they latch. You have some common connections there for those DTC's. I have a DTC that is set because of a marginal connection at the bottom of the fuze box. Its a quick check and costs nothing but a few minutes. Also the fuzes can look good and be bad so check with ohm meter and swap with one from another location just to be sure. My slow refueling problems turned out to be a short internal to the ECM at C2 Pin 8. Had to replace ECM. My DTC for Oxygen sensor heater circuits is caused by a flakey connection between the fuze box and the connector underneath it. The fuze is good but no voltage to the fwd oxygen sensor heaters because connection intermittently goes bad. I just re-seat the fuze box and go on. I will fix it when I get the time.

12-17-11, 03:56 PM
Ok so I tried the seating and that didn't work. I tried sending a ground from the front connector and it didn't make it. Does anyone know where connector C300 is located? I was able to manually ground the solenoid to verify it works (can hear it open and close) so it's definitely a wiring issue (power is making it's way to the solenoid but no ground to open and close it). Any help is appreciated.

12-21-11, 01:24 PM
TTT....anyone have an idea on the location?

12-22-11, 09:28 AM
Well I found my answer on the location of C300. In case anyone needs to know in the future: C300 (8 Cavities).......Chassis harness to engine harness left side of the frame assembly in front of the electronic brake control module.