netsx04

Hi all,

The check engine light came on last week and went away on it's own before I could read the codes. On Sunday the check engine light returned and using my code reader/scanner showed both P0171 and P2195 codes in that order. My gas mileage according to my trip computer is terrible. I have a 2004 Acura TSX with ~202k miles on it. The idle is really rough if I have the AC on it (it flutters between 600-700 rpms). I replaced the the primary O2 sensor (OEM, Denso 234-9066) at ~170k and recently replaced the catalytic converter (walker) and secondary O2 sensor (OE, NTK 24258) at ~198k.

I logged a few of my drives

TexasHonda

Fuel trims (first column LTFT and second column STFT?) are high (lean condition fuel being added). This suggests an intake air leak, low fuel pressure, partially blocked fuel injector. A good test is to rev to 3000 rpm and check fuel trims. If they improve an air leak is likely (leak becomes less significant at higher air flow rate). You can look for air intake leak w/ water sprayed onto key points; intake manifold primarily.

good luck

TexasHonda

P2195 indicates a circuit fault (stuck lean) on the AF sensor. This could cause a false lean causing fuel to be added. Since AF sensor is new look for a damaged wire or connector.

Did 2195 return after AF sensor replaced?

good luck

netsx04

The fuel trims didn't really change running the engine at 3,000 rpm's so I guess the vacuum leak is ruled out. I will try to look at the A/F sensor wiring for signs of damage. Weird thing, the CEL was off on Monday (after my OP) and came back Tuesday (it's still on). Given the age of my car, I wonder if the fuel filter could be a contributing factor?

TexasHonda

Suggest focusing on P2195 as this is a circuit fault (assuming good sensor since new) that should be traceable; short, open, connector. You can verify wiring integrity by disconnecting AF sensor and checking wiring legs from ECM separately for open/short. If you have a capable scanner, you may be able to confirm AF sensor is at high voltage indicating lean condition. Attached diagnostic for your use.

good luck

B Sc

FFwd to 2022, I get the same 'occasional on/off' of this code... after last years same occasional for the OTHER bank p2197
My otherwise excellent mechanic who is fine with helping verbally and letting me do things, suggested a vehicle reset (neg post battery discon. for a minute) and then to not worry about it, just clear the stored DTC with my OBDII. The CEL dashlight went away by itself in two days while I was eyeballing the OBD religiously (distracted driving OOOPS)

But Acurazine shows theres an ancient TSB indicating theres a Honda known bug glitch that triggers this and their 'nominal fee' ECM reprogramming will take care of the odd behavior. Given my GPS 'accuracy' is flaking lately (flipflopping the car icon not sure what direction down hwy all of a sudden), and the famous 15 yr sudden common 'time clock and calendar' glitch, im not impressed with whoever coded their gear.

Wonder if ppl who finally find out about their 'glitch' wind up wasting tons of fuel over the years, fouling plugs and sensors alike as the ECU goes mental for a while... until it corrects itself in a day or two like mine do. Im getting two or three triggers a year in my 04 with 168k kilometers on it.

I am not inclined to believe its wiring now, after seeing that tech bulletin in the other thread. And the sensor, when working, gets me easily 32 to 35 mpg hwy with a 29 average over the years of app-recorded fuel logs.