P0420 p0430 and p0500

Jaci said:

Okay allow me clear something with everyone. I intentionally bought my Xterra as a 2004 as I liked the body and I also love the fact that it was a 5 speed manual. I own a 2003 Volkswagen Beetle, so I do believe I knew what I expected. The timing belt has already been changed along with the water pump. I had the transmission sealed, the clutch redone, the speed sensor, the suspension, shocks, etc. I am not totally clueless. I have been working on cars for quite sometime.

I actually am very hands on with my Xterra. So the knock sensor I did myself. Matter of fact I took it to the auto craft shop and took it apart one day after owning it. Tore the engine down in one day and then the next put it back together in the morning. To finish that job I took it on a road trip that included taking it off road...Following that numerous repairs. I have also done the speedometer sensor after the initial repair at the mechanic failed. I have done the majority of the repairs MYSELF. So before you pass anymore judgment on me you may want to check what I wrote earlier and reread it. I identified the codes. Also I have the Manual on how to do the at home repairs on the 2004 Xterra and the owner’s manual. So I think I know my way quite well around a vehicle to include my Volkswagen 03 and my 04 Xterra. It’s nothing for me to tear it down and work on it. Trust me I don’t waste no time on maintenance as it appears the previous owner who was guy neglected the mess out it. My vehicles are well cared for. So allow me to try again with my issue as the mechanic does not quite know why the codes keeps throwing.

So again here are the codes:
P0500 = SPEED SENSOR (VEHICLE SPEED SENSOR MALFUNCTION)
Possible Causes:
•Faulty Vehicle Speed Sensor (REPAIRED)
•Vehicle speed sensor harness or connectors is open or shorted (Checked and there is no issue)
•Vehicle speed sensor circuit poor electrical connection (Mechanic Said it was fine)
•Faulty Engine Control Module (ECM) (Mechanic Said it was fine)


P0420 = CATALYST SYSTEM EFFIENCY BELOW THRESHOLD (BANK 1)

Possible Causes:
•Three way catalyst converter Bank 1
•Exhaust tube
•Intake air leaks
•Fuel injectors may be faulty
•Fuel injector leaks
•Spark plugs may be faulty (CHANGED)
•Improper ignition timing
•Engine Control Module (ECM)

P0430 = CATALYST SYSTEM EFFIENCY BELOW THRESHOLD (BANK 2)

Possible Causes:
•Three way catalyst converter Bank 2
•Exhaust tube
•Intake air leaks
•Fuel injectors may be faulty
•Fuel injector leaks
•Spark plugs may be faulty
•Improper ignition timing
•Engine Control Module (ECM

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