I have both a P1111 and P1646, what are these and how do you fix them

I think intake air control ???? We don't think ! WE TEST TO KNOW FOR SURE ! What , you read the code an because it stated P1111 NISSAN - Intake Valve Timing Control Solenoid Valve Circuit Bank 1 , you replaced the part . That is not what this code is telling you . Looking up the code in the factory service repair manual an testing the electrical circuits is what should be done .

p0193 sounds like a ip sensor circuit malfunction the p1111 is system check has been completed p1000 system check is not completed..that number will check from 1000 to 1111 when the car has ran a complete self check of itself.

no year, no engine options stated, now that is a challenge. (LOL)
P1111
no my magic, (grin)
GOOGLE.
1st hit,
http://www.carobdcode.com/p1111-honda-intake-valve-timing-control-solenoid-valve-circuit-bank-1

next question is what does it mean.
answer, read the FSM.

p1111 is nothing just letting you know system is ready after codes had been previously cleared, p1646 is 02 Sensor Control Malfuntion Bank 1 Upstream. Possible causes for p1646 o2 sensor went bad,short circuit to ground, short circuit to voltage, or open circuit. Code p1646 bank 1 sensor 1 o2 sensor control malfunction. Bank 1 is the rear bank and sensor 1 is the upstream sensor which you can see if you look between the engine inlet manifold and the brake booster(LHD). It is screwed into the manifold and has the grey connector next to the booster. You can check power to the heater on the white with green stripe wire. Any other testing will require a scan tool with datalogging capabilities. There were some VINs around your year that had their wires for that sensor twisted up by a faulty tool in the factory but you should be able to see that sort of damage easily.

The P1111 unlike the P1000- the P1111 means the ECM has completed a drive cycle with no faults stored. The P1000 means the ECM has not yet completed the drive cycle. They are basicly drive cycle readiness codes doing a system check...this is a natural code..not to worry its checking the car all over between drive cycles for any malfunctions..
sorry i missed u online but the code is nothing to worry about...

The P1111 unlike the P1000- the P1111 means the ECM has completed a drive cycle with no faults stored. The P1000 means the ECM has not yet completed the drive cycle. They are basicly drive cycle readiness codes doing a system check...this is a natural code..not to worry its checking the car all over between drive cycles for any malfunctions..

P1646 is a faulty heater circuit on bank 1 upstream o2 sensor. If you have the V6 2.5 petrol engine, then bank 1 is the exhaust manifold nearest the bulkhead ( firewall if you in the states). Replace the upstream o2 sensor. Cost around £70from dealer...not available elsewhere.

You can check out fault codes at http://www.bluejag.co.uk.
Looks like faulty Lamda Sensor.

Fault Code:- P1646 Indicates a Power-train fault


The fault is generally due to a problem in the Computer & Output Circuit area


Fault Description: ECM HO2 Sensor control malfunction -bank 1 upstream (1/1)

Action of ECM:- ECM Default:- HO1S 1/1 control circuit inhibited


After clearing the DTC, complete the Drive vehicle for 10 minutes
Check for a reoccurrence of fault DTC.

Possible Fault:- HO2 Sensor 1/1 heater failure HO2 Sensor 1/1 sensing circuit: short circuit to ground, short circuit to high voltage, open circuit ECM Failure

P1111 - System Pass
This is flagged after DTCs have been cleared, all engine management OBD diagnostic monitor drive cycles HAVE BEEN COMPLETED.

P1646 - Linear O2 Sensor Control Chip (Bank 1)
Its listed as either a faulty heated HO2 sensor ie lambda sensor (upstream bank 1) or a short (presuming the ECM is OK as no other codes)
Did you replace the right one... bank 1 is at the back of the V6, bank 2 is at the front so its the back one.

Hope this helps (remember to rate tis answer).

P1646 - Evaporative Emission (EVAP) Vent Solenoid Control Circuit