ahhh crap.

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Oct 14, 2007 | 02:10 AM

voodooskyline

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Posts: n/a

ahhh crap.

well. since few days ago, my 98 xj8 has trouble keeping idle. when cold it starts right up but dies and after coming to operating temperature it has hard time staying on. there's no power loss nor miss when i drive the car or rev it from park. it just cannot smooth idle and wants to die! the dtc spit out p1396, which after research jaguar specific dtc says variable timing malfunction circut b. what the hell is that?????? is that the dreaded timing chain tensioner defect? the car seems to run fine without loss of power and it's smooth, yet can't retain smooth idle if it's life depended on it! i'm inches away from driving this car through the dealer front door! help!

Oct 14, 2007 | 04:49 PM

Max

Senior Member

Joined: Oct 2005

Posts: 199

Likes: 11

From: Southwest Pennsylvania, U.S.A.

RE: ahhh crap.

Here is what the JTIS lists as posssible problems for the P1396. Has nothing to do with tensioners.

ECM to VVT solenoid valve circuit fault
(refer to P1392, P1393) - see below -
VVT solenoid valve actuator sticking
Oil supply fault
VVT unit fault
Camshaft drive fault
CKPS / CMPS circuits fault(s)
(refer to P0335, P0340) - see below -

P1392
Fault - ECM to VVT solenoid valve circuit open circuit, A bank
Possible causes - ECM to VVT solenoid valve circuit open circuit,
high resistance, short circuit to high voltage
VVT solenoid valve failure

P1393
Fault - VVT solenoid circuit short circuit A bank
Possible causes - ECM to VVT solenoid valve short circuit to ground
VVT solenoid valve failure

P0335
Fault - CKPS circuit malfunction
Possible causes - CKPS disconnected
CKPS gap incorrect / foreign matter on sensor face
CKPS sensing circuit open circuit, short circuit to ground, short circuit to high voltage CKPS failure

P0340
Fault - CMPS circuit malfunction
Possible causes - CMPS disconnected
CMPS gap incorrect / foreign matter on sensor face
CMPS sensing circuit open circuit, short circuit to ground, short circuit to high voltage
CMPS failure

Jan 6, 2008 | 06:03 PM

FactoryJaguarTech

Joined: Jan 2008

Posts: 2,961

Likes: 89

From: 33498

RE: ahhh crap.

This is not timing chain tensioners. This indicates the VVT unit is bad. Either blocked or bad solenoid. A bank is passenger side (U.S.A). The VVT unit is in front of engine at top. I think you said 98 car. I think they changed half way thru model year to on top of cam covers at front of engine. If you have to replace them, do the tensioners at this time. Will save you thousands in the future.

Oct 10, 2020 | 09:01 PM

edreddy

Member

Joined: Mar 2018

Posts: 50

Likes: 5

From: Calgary

I can definitely do the primary and secondary tensioners. How do I figure the time chain to ensure it’s properly set after I replace the tensioners?

Oct 11, 2020 | 08:08 AM

Highhorse

Veteran Member

Joined: Feb 2013

Posts: 4,936

Likes: 1,928

From: Trying to escape Central Florida

Review this old (but still applicable) detailed thread by blackonyx on doing the chains and locking the cams, its pretty cut and dry.

Tmingi chain and tensioner replacement

Found in the "How To" section at the top of this forum... https://www.jaguarforums.com/forum/x...k-links-20090/