XJ-6 L6-4.0L (1991)
Oxygen Sensor: Technical Service Bulletins
DTC 44 - Diagnosing Oxygen Sensor
18-30
MODEL: 90-93 MY Sedans
DATE: 4/93
Diagnostic Trouble Code 44 - Oxygen Sensor - Install Splash Shield
SUPERSEDES: TECHNICAL BULLETIN 18-17
ISSUE:
An oxygen sensor splash shield has been introduced on sedans from VIN 664941 and on all 93 MY XJS vehicles to prevent intermittent display of
Diagnostic Trouble Code (DTC) 44.
ACTION:
^
Whenever replacing an oxygen sensor, make sure the splash shield is in place. On pre-VIN 664941 vehicles, install a splash shield (C 33139/4). Slide
the splash shield down to cover the whole sensor, (Fig. 1).
^
If DTC 44 is displayed, check for any other stored codes. Use JDS "Engine Management - Fault Diagnosis" to read the fault table.
^
Make a note of all stored trouble code(s), then exit "Fault Diagnosis". Record preset radio stations and erase the trouble code(s) by disconnection and
reconnecting the battery.
^
Run the engine to normal operating temperature. Enter JDS "Vehicle Set-Up/Individual Tests" and select "Lambda Signals".
^
If "Lambda Feedback" voltage is correct (between 1 and 4 volts) and only DTC 44 was stored, the fault is intermittent. Install an Oxygen Sensor
Splash Shield (C 33139/4).
^
If "Lambda Feedback" voltage is correct and DTC 44 was combined with DTC 26, suspect intermittent fuel pressure loss. Test and inspect the fuel
delivery system.
^
If "Lambda Feedback" voltage is less than 1 volt, a fault is present. Suspect faults in the following areas:
High fuel pressure.
Injectors leaking.
Purge valve stuck open.
Engine ground or oxygen sensor heater ground loose.
Incorrect air mass meter calibration.
^
If "Lambda Feedback" voltage is more than 4 volts, a fault is present. Suspect faults in the following areas:
Intake manifold air leak.
Low fuel pressure.
Purge valve stuck open.
