http://engine-codes.com/p0451.html
Situation is I was getting P0171/P0174 (bank 1/bank 2 lean) codes for a while. They'd pop up spontaneously and seemingly randomly. OK, might be an O2 sensor, but I monitored for a while. Now they've gone away. Related? Can a P0451 cause O2s to read lean?
A couple weeks ago, the P0451 popped up after refueling. I did not overfill, which seems to set it off. I have not experienced the fueling issue that a lot of 05-06 owners seem to complain about.
I tried swapping fuel caps with my truck, and the issue still exists, so I ruled out the fuel cap. The hoses under the vehicle look fine, so I have ruled that out as well.
I did have the water leak issue on the passenger side, and it screwed up my SJB...I had the electronics go haywire for a short while and I now have daytime running lights. This occurred at least a month before I got the P0451 code - could it be related? I thought the ECM controlled the EVAP stuff, not the SJB?
I'm just at a loss now as far as troubleshooting. I'm thinking it's the sensor, but how can I check that? It seems as if I'm gonna have to let a "professional" look at it which is the last thing I want to do. Thoughts?
_____________________
Just an update for posterity, if anyone comes across this thread. It was the fuel tank pressure sensor.
P0451 - Evaporative Emission Control System Pressure Sensor Range/Performance
Possible causes
- Faulty Evaporative Emission System (EVAP) Pressure Sensor
- Evaporative Emission System (EVAP) Pressure sensor harness is open or shorted
- Evaporative Emission System (EVAP) Pressure sensor circuit poor electrical connection
- Faulty Engine Control Module (ECM)
When is the code detected?
An improper voltage signal from EVAP control system pressure sensor is sent to Engine Control Module (ECM).
Possible symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
P0451 Description
The Evaporative Emission System (EVAP) control system pressure sensor detects pressure in the purge line. The sensor output voltage to the Engine Control Module (ECM) increases as pressure increases. The EVAP control system pressure sensor is not used to control the engine system. It is used only for on board diagnosis.
Situation is I was getting P0171/P0174 (bank 1/bank 2 lean) codes for a while. They'd pop up spontaneously and seemingly randomly. OK, might be an O2 sensor, but I monitored for a while. Now they've gone away. Related? Can a P0451 cause O2s to read lean?
A couple weeks ago, the P0451 popped up after refueling. I did not overfill, which seems to set it off. I have not experienced the fueling issue that a lot of 05-06 owners seem to complain about.
I tried swapping fuel caps with my truck, and the issue still exists, so I ruled out the fuel cap. The hoses under the vehicle look fine, so I have ruled that out as well.
I did have the water leak issue on the passenger side, and it screwed up my SJB...I had the electronics go haywire for a short while and I now have daytime running lights. This occurred at least a month before I got the P0451 code - could it be related? I thought the ECM controlled the EVAP stuff, not the SJB?
I'm just at a loss now as far as troubleshooting. I'm thinking it's the sensor, but how can I check that? It seems as if I'm gonna have to let a "professional" look at it which is the last thing I want to do. Thoughts?
_____________________
Just an update for posterity, if anyone comes across this thread. It was the fuel tank pressure sensor.
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