Code P0420, 2002 Nissan Altima Sedan

Question

2002 Nissan Altima Sedan (Miles - 130,000) with 2.5 L 4-Cylinder, Automatic Transmission. Replaced the Old Battery (Battery would not hold a charge): 1st - Disconnected the Negative, 2nd - Disconnected the Positive then removed then removed the battery.

Engine will turnover but will not crank?

This is my Daily Commuter and has been working fine.
The car has been sitting for 5 Days from vacation last week?

After the Battery was installed went through the Flashing sequence of the Service Engine Light.

My understanding of the Light Sequence 4-Digit Code:

10 Flashes = 0
1 Flash = 1
2 Flashes = 2
Thru, 9 Flashes = 9

First Code:
1st Number : Slow Flashes
Brief Pause
2nd Number : Quick Blinks
Brief Pause
3rd Number : Quick Blinks
Brief Pause
4th Number : Quick Blinks

Longer Pause = Then the next code will start.

These are the codes:

P0420 = Catalyst System Efficiency Below Threshold (Bank 1)
P1001 - ? - Not Sure what this code is ?
P1000 - ? - Not Sure what this code is ?

Any advice ?

Thanks

Answer 1

the 2002 Nissan Altima does not use p1000 and p1001 codes. 

P0420 is for mainly for the catalyst converter being bad, but I would figure out the other codes before.

using an OBD-II reader to get the code is fastest and most accurate way. also OBD-II are pretty cheap now a days.

If you have an android phone and would like a bluetooth OBD-II reader we sell them on the site for $15 

https://www.autocodes.com/diagnostic.php