Figured I'd throw this one up here and see if any other mechanics have run into this code before.
Customer came in with a check engine light complaint. Confirmed codes P1283 and P1800. MAF and B2S1 AFR sensor were replaced by customer. Unknown brand of AFR sensor more than likely Bosch.
Visual inspection showed rotted PCV hose. Replaced PCV hose.
A/F Alpha on B2 showed roughly 125%
B2S1 Voltage showed sub 1.4v
Rear O2s had good range and responded to changes (creating a vacuum leak/adding fuel). Engine vacuum roughly 20inHg
MAF passed VE check
Other sensors ECT, IAT, MAP, BARO looked OK
Cleared the code and self learn. Within a few drive cycles P1283 came back.
Smoke tested the intake (cold). No visible leak. Sprayed with soapy water confirmed no vacuum leaks.
Per TSB NTB04-019A checked B2 catalytic converter for loose/missing bolts. All bolts secure and present.
Smoke tested the exhaust. No exhaust leaks found.
Per TSB NTB04-090 ohmed the injectors. All injectors had roughly 14ohms @ 157*F.
At this point I opted to replace the AFR sensor with an NTK (OE brand).
Replaced the AFR sensor, cleared the code and self learn and drove for monitors. The O2 monitor took a few drive cycles to pass so something seemingly was wrong, but scan data showed A/F alpha right around 105% and sensor voltage at around 1.5v. Eventually it passed the monitor and got it's inspection sticker. Mode $6 confirmed test passed with some margin.
Given the presence of TSBs I would think that this code (P1283) isn't that uncommon. Though this is the only time I've ever run into the code.
Has anyone ever ran into this issue before? And if so what was the cause/final solution?