I get code p1273 (bank 1 sensor 1 lean) i have taken it to the dealership thay have told me the car is in spec on its STFT but off by 4% on the LTFT they told me to replace the bank1 sensor 1 i have since done so on my own with a bosch wideband and cleared the code 6 miles later it has come back on i am now thinking it must be a:
head gasket leak, intake manifold leak, or exhaust leak? anything before this i would assume would throw both banks sensors off!
Please help me narrow it down and solve this problem i have spent many hours on it and cant find the culprit!

 

This should help some. I would check for an exhaust leak around the Cat also.


DTC: P1273

Search Bulletins/Recalls for P1273

Trouble diagnosis name: Air fuel ratio (A/F) sensor 1 (Bank 1) lean shift monitoring

Component Description:

The A/F sensor is a planar dual-cell limit current sensor. The sensor element of the A/F sensor is the combination of a Nernst concentration cell (sensor cell) with an oxygen-pump cell, which transports ions. It has a heater in the element.

The sensor is capable of precise measurement λ= 1, but also in the lean and rich range. Together with its control electronics, the sensor outputs a clear, continuous signal throughout a wide λ range (0.7 < λ < air).

The exhaust gas components diffuse through the diffusion gap at the electrode of the oxygen pump and Nernst concentration cell, where they are brought to thermodynamic balance.

An electronic circuit controls the pump current through the oxygen-pump cell so that the composition of the exhaust gas in the diffusion gap remains constant at λ = 1. Therefore, the A/F sensor is able to indicate air/fuel ratio by this pumping of current. In addition, a heater is integrated in the sensor to ensure the required operating temperature of 700 - 800°C (1,292 - 1,472°F).

DTC detecting condition:

* The output voltage computed by ECM from the A/F sensor 1 (Bank 1) signal is shifted to the lean side for a specified period.

Possible cause:

* Air fuel ratio (A/F) sensor 1
* Air fuel ratio (A/F) sensor 1 heater
* Fuel pressure
* Fuel injector
* Intake air leaks

 

Thanks but that is info i already know of i have isolated the problem to the few locations i have listed i know what code p1273 is and what a O2 air fuel sensor is it cant be the top 2 of the possible causes you listed because i just replaced sensor 1 with a bosch oem sensor looked up specific to my vin part # from dealership, and the other possable causes are not likely since they would register a error in both bank 1 sensor 1 and bank 2 sensor 1!

Has anyone had a similair problem?
Most importantly How do i go about finding the exact issue and fixing it? (ie. spraying head gasket with carb cleaner to hear for idle change indicating a head gasket leak!) but for my other possable issues!

 

I just got this damn code today. I have lots of mods..everything cept headers. I think i am running way lean...Looked this code up and says air/fuel ratio sensor 1. P1273 Here's my mods "Its my signature from the other Z site..didnt feel like separating non performance mods"

255.01RWHP 238LBs Torque@6,461RPMs
S2K stubby antenna
Custom Hatch Struts By JasonZ-YA
3%tint on all back..25%front tint
Cobra Radar/Laser Detector
Dual cd770 cd/mp3/wma player
Rockford Fosgate 600W amp
2 Jl-audio W3v3.4 Subs with custom zenclosure box
JDM Fairlady Z Emblem
Stillen Engine Damper
Helix Power Tower Plus 1"Throttle Body Spacer
Megan-Racing Y-pipe 2.5"IN/3"OUT
JWT Popcharger SRI
1/2" Iso Thermal Plenum spacer by Motordyne
Berk's Technology polished aluminum suction air intake tube
Blue LED License Plate Lights
Fairlady Third Brake light decal-By Zeetoyz
Top Speed Resonated Test Pipes w/o2 fix
Poly-V Serpentine/ac "gator belts" by goodyear
Top Speed Pro N1 3" Catback Exhaust
Hawks HPS ferro-Carbon Brake Pads(all 4)

I need to get car inspected but cant with this light..Can i clear it? Or what is the deal with this

 

I got this one the moment I went to a HFC. It more than likely has something to do with the actually mixture. Whether its from too much air or too little fuel I know mine is on the lean side. I'm personally thinking my problem is fuel related.

 

I have had this code due to an intake leak. It did not register on both banks. Do not assume that just because you only got the reading on one side that it therefore follows that the problem must be isolated to a problem that must only affect one bank. It doesn't work that way, not in practice.

I've had a problem with this code twice. Once I had a crack in the crankcase ventilation hose connector nipple on the intake tube. I actually epoxied the crack and wrapped it in electrical tape for good measure.

The other time I had the P1273 code I corrected the problem by cleaning, re-seating and tightening really well the intake tube connections to the throttle body and the air box. I think I hadn't seated and tightened it to the air box sufficiently well. Rather than just snugging them, I now tighten them quite hard.

I speak from my personal experience. I will mention another code thrown from one side only go, I had the P0430 code (insufficient catalytic converter efficiency) thrown a while after installing a metallic substrate HFC. When I got around to removing and inspecting the cats, both cats were devoid of substrate, i.e. they had both burned out their cores and become test pipes. Only the right bank ever registered a check engine light. The left bank never registered a code in spite of there being NO catalytic converter. All this only goes to say that a reading too much into a "one bank only" code is not a good diagnostic process.

Check your intake for any leaks, its one of the easiest places for a cause for the P1273 code and it costs nothing to go through and check and tighten up the connections.

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