Wednesday, October 9, 2013

P1646 and P1647 on your XJ

P1646 and P1647 are two mighty and very common Oxygen sensor codes. The first (P1646 is for the right bank, here in the USA that's the passenger side) and the other (P1647 is for the left bank or driver's side in the USA). The probable causes are:
  1. Oxygen sensor failure: fixes the problem 95% of the time
  2. Oxygen sensor circuit failure (either the connector or the cable going to the computer): Fixes the problem 1% of the time 
  3. Computer failure: fixes the problem 4% of the time
The computer is constantly comparing the upstream Oxygen sensors with the downstream oxygen sensors so it is always recommended to change them in pairs (front and rear for each bank). All you have to do to fix your code is to replace both oxygen sensors respective to your bank. For a guide on which parts to buy look below:

Question: What oxygen sensors do I need?
Answer: Depends on what car... Buy one of each, here is a guide:

1997 - 1998 XJ8 with a 3.2L and a 4.0L engine

1999 - 2003 XJ8 with a 3.2L and a 4.0L engine

2003 - 2005 XJ with a 4.2L engine

2006 - 2009 XJ with a 4.2L engine

1 comment:

  1. I have a 10 year old 2004 Jaguar XJ8 95,000 miles. Have had confusing problems. Bought a couple aftermarket sensors with a Denso replacing combination of original and Denso. Just kept having codes appear on O2 sensor shorts. I Did use 2 Denso sensors then a couple after market sensors for upstream Denso downstream which seems to be no problem there. Then I had problems with upstream replacing one with Denso and one aftermarket upstream. So I switched sides and then my handheld computer called it a short in right side but left is OK. Then I switched again and now opposite reading is showing up. I am now looking to add a Denso 234-9030 to the right side also as I think it has to be aftermarket problem.Denso is much more expensive but with a box of aftermarket now I wish I had went with all originals. After I install the new Denso I may re-post the results for others.