chenxingha

I got the P1130 code readout at my local AutoZone store that I have trouble making precise understanding. The readout/printout is as follows:

Troubleshooting P1130

OEM Brand: Lexus

Definition:

Air/Fuel ratio sensor circuit range/performance malfunction (bank 1 sensor 1)

Probable cause:

1. Fuel pump, injector or presure regulator fault
2. Vaccum leak on engine
3. Faulty AF sensor heater circuit
4. Failed AF sensor

My reading of the DIY and posts related to P1130 code seems to be that it points to the failure of either or both A/F sensors. But this "Probable cause" generated by an AutoZone staff got me confused: the #1 cause is fuel pump?

My daughter's 2000 RX300 has just developed this on-again off-again CHECK ENGINE light issue and I drove to the local store (with the CE light on) and had the code scan. The vehicle is near 113k miles and is pushing for 120k by year end.

Thank you, the many experts on this forum. I learned doing many minor fix/repair work with advices on this forum. With my wife uses the other 2000 RX300 vehicle in the house, I have my hands full.

Lexmex

It's just one A/F sensor giving the issue (the rear one behind the engine).

For me, I find it to be a necessity now to either have a handheld OBD2 scanner that can read A/F sensor readings, have a laptop with appropriate software to hookup to the vehicle to read the readings or have a mechanical buddy who has one of the two things. I chose the laptop method as that would show what is specifically going on with the readings and see if indeed the A/F sensor is gone on the way out, etc.

If this were a fuel pump or injector you'd notice other things like hesitation/misfiring, etc. There might be a small leak around the manifold near that A/F sensor (I've had that issue on the front one in the engine bay before).

Zieke

I had the Bank 1 Sensor 1 replaced by a dealer about 10k ago, Don't know the brand. I repl. the front one around 4k miles ago with a Denso. one wk. ago the battery started going bad (clock resets) so replaced it,at which time the 1130 code started appearing and comes back on after resetting the code. Does that indicate the Bank one sensor is defective again?
Thanks Zieke

amblyn

1130 in my case was a bad bank 1 sensor one air/fuel sensor. The dealer will install toyota sensor made by denso so dont see why went bad after 10k hate to tell you to go pay dealer prices again but i would go back to dealer who installed it see if they will check it out. i would also check the sensors connection. if you arms and hands arent to big climb under car jack it up if need be passenger side at about as far back as pass front wheel you will see it up there follow wire make sure plug is connected good. unplug and reconnect if possible. also read somewhere that if you have leaking fluids i.e. oil or something and gets on sensor can cause bad reading or cause sensor to go bad. you can also search this forum and find a DIY guide on how to check resistance with a meter to see if sensor is good or bad good luck.. try to find something thats making sensor go bad prematurely before putting a new one in

amblyn

yea those autozone printouts are very general kind of lists all possibilities the causes are in no particular order if both af sensors were out you would have more codes.

you say on and off does it turn itself off if so as another mentioned above could be a leak near sensor wich will cause sensor to give bad reading. i have a leak right before o2 sensor under driver seat code come on 2 days off 3 etc. i applied this patch stuff from autozone wich i only recomend as a temp fix or if you poor like me haha codes gone mean sensors good. you should also look for post how to test resistance check if sensors good or bad but first check for any sort of exhaust leaks