1998 JAGUAR X308 oxygen

Exhaust System -
Torques


ComponentNm
Nut - Downpipe catalytic converter to exhaust manifold14 - 18
Bolt - Downpipe catalytic converter to lower mounting bracket39 - 51
Bolt - Front muffler mounting to gearbox (SC)22 - 28
Bolt - Front muffler mounting to front muffler cross brace (SC)22 - 28
Bolt - Over-axle mounting to rear suspension A-frame22 - 28
Torca clamps52 - 68
Oxygen sensor to downpipe40 - 50

The left-hand and right-hand do wnpipe assemblies feature:
Catalytic converter with palladium / rhodium coated elem ents. The elements are uncoated for markets with only
leaded fuel.
Retained to the exhaust manifold flange by four thread ed studs. Joint-to-joint sealing is with a gasket. Engine-mounted bracket providing downpipe mounting by two nuts to the torque converter housing and two bolts to
the downpipe.
Front Muffler Assembly
ItemPart NumberDescription
1—Downpipe catalytic converter
2—Upstream heated oxygen sensor
3—Downstream oxygen sensor (North American markets only)
4—Engine mounting bracket (LHS and RHS)

Joints and Clamps

Pipe-to-pipe joints which are slip joints, feature:
Clamping by Torca strap clamp. Indicator rings providing Maximum, Mini mum and Nominal engagement marks.
Oxygen Sensor (O2)
Location

Parts List
Operation
ItemPart NumberDescription
1—Heated oxygen sensor (upstream)
2—Oxygen sensor (downstream)
3—Catalytic converter

The upstream heated oxygen sensor is located at the catalytic converter inlet and detects the concentration of oxygen in the
raw exhaust gases; an internal heater reduces the warm up time of the sensor output.
An oxygen sensor (without heater) is located at the converter outlet.
The ECM receives input signals from the se nsors and varies the fuel injector duration (mixture) to provide optimum gas
emissions.
Circuit Diagram, O2 Sensors / ECM

Inspection and Verification
Vehicle Harness Check
1.1. Check for open and short circuit in harness conn ector faults between the O2 sensor and ECM.
2. 2. Check for approximately 12V between heater harness.
ItemDescription
1ECM
2Downstream oxygen sensor (A)
3Upstream heated oxygen sensor (A)
4Downstream oxygen sensor (B)
5Upstream heated oxygen sensor (B)
6Engine management fuse box

Exha
ust System - Catalyti
c Converter LH4.0L NA V8 - AJ27/3.2L NA V8 -
AJ26
Re mo
val and Installation
Remova

l
1.
Op
en the engine compartment and fit paintwork protection
sheets.
2. Remove the front muffler; refer to Operation 30.10.18 in this
section.

3. Re
move the centre trim panel
from the engine compartment.
1. Remove the left hand side enclosure panel.
2. Remove the centre trim panel.

4. Repo
sition the expansion tank from the mounting.
1. Disconnect the coolant level sensor connector.
2. Remove the nuts which secures the tank.

5. CAUT
ION: Note the position of the upstream and
downstream (where fitted) o xygen sensor multiplugs for
reassembly.
Disconnect the oxygen sensor multiplugs.
Di spl
ace the multiplugs from the engine mounting bracket.

Dis
connect the plug(s) from the oxygen sensor(s)
6.
Re
move the four nuts which se
cure the downpipe catalytic
converter to the exhaust manifold.

I
nstallation

7.
R
aise the vehicle on a ramp.

8. R
emove the downpipe catalytic converter.
R

emove the bolts which se
cure the downpipe lower
mounting bracket.
Remove the
downpipe assembly.

9. R
emove the oxygen sensor(s).
The downstream sensor i

s fitt
ed only for North American
markets.
10. Remove gasket from the manifold flange.
Clean and inspect th
e manifold joint faces.
Clean and inspect th

e threads
on the downpipe studs.
1. Fit the oxygen sensor(s).
The downstream sensor i
s fitt
ed only for North American
markets.