1998 JAGUAR X308 ignition switch

Connect the scan tool 1
Have the DTC(s) and freeze frame data been recorded?
Yes GO to B2
B2: CHECK FOR LOW EX HAUST TEMPERATURE
Check the engine and exhaust system for normal running
temperature 1
Is the engine and exhaust sy stem up to normal running
temperature?
Yes GO to B3
No Rectify possible leaking exhaust manifold / catalyst, general
causes of an over rich mixture and engine cooling system
operation. Test the system for correct operation.
GO to B8
B3: CHECK FOR O2 SENS OR HEATER CONTINUITY
Ignition switch to position 0 1
Disconnect EM021
Bracket on top of gearbox or Bulkhead rear of engine
2
With EM021 disconnected, measure the resistance between
EM021/001 and EM021/002. 3
Is the resistance between 4 and 10 OHM?
Yes
GO to B4
No Renew O2 sensor, reconnect plug(s).
GO to B8
B4: CHECK FOR O2 SENSOR FAILURE

Ignition switch to position 0 1
Disconnect EM010
Inside ECM housing
2
Disconnect EM012
Inside ECM housing
3
Ignition switch to position II 4
Measure the voltage between EM010/023 and EM012/015. 5
Is the voltage 0 (zero) V?
Yes GO to B16
No Inspect harness / connectors EM010, EM012 and EM021 for
corrosion, damaged / pushed back pins. Repair as necessary
and reconnect plug(s).
GO to B19
B16: CHECK FOR SHORT TO B+
Measure the voltage between EM010/023 and EM012/022 1

Ignition switch to position 0 1
Remove EMS fuse F14. 2
Disconnect EM010 and EM015. 3
Using a link lead, bridge EM010/016 and EM010/022. 4
Ignition switch to position II 5
Measure the voltage between EM010/023 and EM015/002. 6
Is the voltage 0 (zero) V?
Yes Replace EMS fuse F14 but retain link lead.
GO to B18
No Inspect harness / connectors EM010, EM015 and EM021 for
corrosion, damaged / pushed back pins. Repair as necessary
and reconnect plug(s).
GO to B19
B18: CHECK B+ AT O2 SENSOR HEATER CIRCUIT

Connect the scan tool 1
Have the DTC(s) and freeze frame data been recorded?
Yes GO to C2
C2: CHECK FOR O2 SENSOR FAILURE
Ignition switch to position II 1
Disconnect EM022
Bracket on top of gearbox or Bulkhead rear of engine
2
Run the engine for a period to warm the sensor and then
maintain a steady speed of approximately 2500 rpm. 3
Measure the voltage between EM022/001 and EM022/002. 4
Is the voltage between 600mV and 1.0 Volt?
Yes
GO to C3
No Renew O2 sensor and reconnect plug(s).
GO to C6
C3: CHECK FOR O2 SENSOR FAILURE
With the conditions held as C2, suddenly decelerate to idle. 1
Has the voltage dropped to 400mV or less ?
Yes

Ignition switch to position 0 1
Disconnect EM010
Inside ECM housing
2
Disconnect EM012
Inside ECM housing
3
Measure the voltage between EM010/023 and EM012/017. 4
Ignition switch to position II 5
Is the voltage 0 (zero) V?
Yes GO to C15
No Inspect harness / connectors EM010, EM012, and EM022 for
corrosion, damaged / pushed back pins. Repair as required
and reconnect plug(s).
GO to C18
C15: CHECK FOR SHORT TO B+

Ignition switch to position 0 1
Disconnect EM010
Inside ECM housing
2
Disconnect EM012
Inside ECM housing
3
Ignition switch to position II 4
Measure the voltage between EM010/023 and EM012/015. 5
Is the voltage 0V?
Yes GO to D18
No Inspect harness / connectors EM010, EM012 and EM022 for
corrosion, damaged / pushed back pins.
Repair as required an d reconnect plug(s).
GO to D21
D18: CHECK FOR SHORT TO B+

Connect the scan tool 1
Have the DTC(s) and freeze frame data been recorded?
Yes GO to E2
E2: CHECK O2 SENSOR HEATER CONTINUITY
Ignition switch to position 0 1
Disconnect EM023
Bracket on top of gearbox or Bulkhead rear of engine
2
Measure the resistance between EM023/001 and
EM023/002. 3
Is the resistance between 4 and 10 OHM?
Yes
GO to E3
No Renew O2 sensor. Reconnect plug(s)
GO to E7
E3: CHECK FOR O2 SENSOR FAILURE

Ignition switch to position 0 1
Remove EMS fuse F14. 2
Disconnect EM010 and EM015. 3
Using a link lead, bridge EM010/016 and EM010/022. 4
Measure the voltage between EM010/023 and
EM015/001. 5
Is the voltage 0 (zero) V?
Yes Replace EMS fuse F14 but retain link lead.
GO to E17
No Inspect harness / connecto rs EM010, EM015, and EM023
for corrosion, damaged / pushed back pins.
Repair as required an d reconnect plug(s).
GO to E18
E17: CHECK B+ AT O2 SENSOR HEATER CIRCUIT