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Daniel Wilson
Daniel Wilson,
Category: Jaguar
Satisfied Customers: 5586
Experience:  Owner at DJ Wilson
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My 1999 XJ8L 4.0 started running rough and Check Engine

Customer Question

My 1999 XJ8L 4.0 started running rough and Check Engine light came on. Checked codes and came back with P0332 (Knock Sensor 2 Circuit Low Input-Bank 2), P1647 (B bank upstream oxygen sensor), and P1600 (Loss of KAM Power; Open Circuit). I replace the O2 and knock sensors, cleared codes, but car is still running rough and am still getting P1647 and P1600. The "running rough" is like the car looses power for a brief moment repeatedly, especially when going above 50mph, and sometime when accelerating normally from a stop.
Submitted: 1 year ago.
Category: Jaguar
Customer: replied 1 year ago.
To clarify - the O2 sensor I replaced was the one on the right (passenger) side, top of the catalytic converter, and it had the grey connector. Replaced with a Bosch 15627. Battery was disconnected.
Expert:  Daniel Wilson replied 1 year ago.

Hi my name is***** with me while I pull up your codes and some information to help.

Customer: replied 1 year ago.
I'm still waiting on an answer...
Expert:  Daniel Wilson replied 1 year ago.

Hi Matthew. My sincere apologies about the delay. I am glad you posted back. Experts are not employees of the site. I help on here in between jobs as time allows and had a few emergency calls I had to go out on and got tied up. If you replaced both O2 sensors and the code still exists then test and inspect the wiring harness between the sensor and PCM for any damage or corrosion in the harness. Test for continuity with an OHM meter. If the harness test good and the sensor is good it points to a problem in the PCM

Customer: replied 1 year ago.
What does P1600 (Loss of KAM Power; Open Circuit) indicate?
Expert:  Daniel Wilson replied 1 year ago.

The 1600 fault actually confirms an internal problem with your PCM. Replace your PCM

P1600 ECM Battery Back-up Circuit Fault

Expert:  Daniel Wilson replied 1 year ago.

the internal battery that Keeps the memory alive has failed

Customer: replied 1 year ago.
OK, just for my understanding, what is your experience history with the X308?
Expert:  Daniel Wilson replied 1 year ago.

I have a repair business and work on multiple makes and have been a technician in the industry since 1995 and had two years automotive certificate and a diesel degree prior to that

Expert:  Daniel Wilson replied 1 year ago.

First test all your power and grounds to the PCM and confirm no open circuits or problems in the harness. Be sure all fuses test good

Customer: replied 1 year ago.
Can you help me better understand why a bad O2 sensor would only noticeably cause issues above 50mph?
Expert:  Daniel Wilson replied 1 year ago.

Sure. The PCM monitors the upstream O2 values before the cat and then compares them downstream form the sensor after the Cat and those values get read by the PCM to make any necessary adjustment with EGR, fuel trim, etc. when you have any vacuum leaks, EGR valve problems, exhaust leaks or restrictions it will throw those expected readings off. If the PCM itself has internal issues or software issues it can also cause multiple faults to occur

Customer: replied 1 year ago.
OK, thank you - nothing personal, but I'd like to have someone who has direct experience with the X308 take a shot at my question. These cars have very distinct quirks and I'd like to get input from someone who has access to the Jag technical bulletins and has worked on enough of them to understand their quirks. I believe there is a mechanic on here that goes by Richard who has extensive Jaguar experience if you wouldn't mind kicking it over to him. Thank you.