- This topic has 14 replies, 2 voices, and was last updated 6 years, 4 months ago by
.
-
Topic
-
Code P1273 I have replaced the o2 Sensor and the Mass Air Flow Sensor, and all 4 injectors still getting this code the car seems to run fine except upon acceleration
it sounds like a lifter is sticking will this cause this code? o2 sensor is stuck lean bank 1 .295v richer on bank 2 .640v after cat. I can’t find any vacuum leaks round suspect places intake, injectors, mass air ducting, etc. any other ideas?
-
Replies
-
P1273:
Possible causes
Faulty Air fuel ratio (A/F) Sensor 1 Bank 1
Air fuel ratio (A/F) Sensor 1 Bank 1 harness is open or shorted
Air fuel ratio (A/F) Sensor 1 Bank 1 circuit poor electrical connection
Fuel pressure
Faulty Fuel injector
Faulty Air Flow Meter[b][size=4]If one or more sensors are replaced the Engine Control Module (ECM) Mixture Ratio Self-Learning clearing procedure must be perform.
[/size][/b]
Instructions1 Start engine and warm it up to normal operating temperature.
2 Turn ignition switch OFF.
3 Disconnect mass air flow sensor harness connector, and restart and run engine for at least 3 seconds at idle speed.
4 Stop engine and reconnect mass air flow sensor harness connector.
5 Make sure Detected Trouble Code (DTC) P0102 is displayed.
6 Erase the DTC memory. (This could be done by disconnecting the car battery for 30-45 min or with a scanner)
7 Make sure no codes are stored in the ECM.
8 Run engine for at least 10 minutes at idle speed.
9 Drive vehicle for 8 – 25 miles until ECU commands new LTFT mapping.
( Having a scan tool with fuel trims on screen will show when LTFT become active. );
I performed the reset as you directed it appeared to have worked for about 35 miles then it threw code p0455.
Then p1273 soft code again. I replaced the gas cap and the evap purge valve for the p0455. I cleared the codes and drove it another 12 miles and the p01273 soft code appeared again. code p0455 has not returned yet. Should I perform the ecm reset again since this happened and try again?Let me understand you..
You stated you replaced a O2 sensor, but the code is for the A/F Sensor.
This TSB might also apply to you.
https://www.autocodes.com/uploads/nissan/NTB04-027a.pdfI think I may have found the problem as the fuel pump. My book states pressure to be 48-54psi
When I connected the fuel pressure gage I get a reading of 42psi after I turn the key it instantly goes to 50psi and instantly back to 42lbs and slowly drops to about
35psi after 5 min which is within the 30-40psi range. this is just a key on pressure test not running.
Any verification that this is the problem would make me feel better about dropping $250 for the fuel pump.I performed the fuel chart ecm reset again after the p0455 code for the purge valve drove 40 miles before the p1273 code came back it made a huge difference in overall performance.
no other codes are present currently except p1273Pressure does appear to be a bit on the low side.
Did you try with the engine running?
If not, you should.
If it remains below minimum specs with the engine running that might be the issue.
You should also check the pressure regulator for proper function.[video]https://youtu.be/F7_tQPfST6A[/video]
This is what I’m seeing at the firewall directly from the pump. Nissan has no Schrader valve of course so I will have to rig it somehow to do that engine running test.
I will try this and keep you posted.Ok, it looks like it may not be the pump after all running psi is fluxing between 48-51 after reving a little it stable at 51psi
I truly have no idea why this code is happening. I think the regulator is built into the pump in the tank.
I have tried everything I can think of any ideas or more help on this code is greatly appreciated.You stated this:
it sounds like a lifter is sticking
I am wondering if perhaps you have a exhaust leak either at the manifold or some along the piping tripping your code.It’s quite as new although that does not mean it could not still be that.
I’m pretty sure it is a lifter making the noise, but it almost went away completely after performing the ecm fuel reset and drive.I wanted to post an update of my findings for everyone.
I went to replace the head and found that inside the intake manifold there are these
butterfly plates with screws. One of these plates came off and was inside my intake port on my head. I think i may have found my problem. Any one think this was causing the p1273 code i was seeing? when i get it all back together i will post and update this again. Thank you for the help !This is exactly how I found it blocking off the intake port. You can see that it has been in there for a while chewing on the intake port. The screws went through and were inside the exhaust header/ cat instead of the cylinder #4
- You must be logged in to reply to this topic.