MIL ON - DTCs 23,34,36,44 or 45 Air Injection
18-27Check Engine Warning and Diagnostic Codes - Air
Injection Thermo-vacuum Valve -
Incorrect Calibration
MODEL:
92 MY XJS
DATE:
11/92
ISSUE:
The Check Engine warning light and diagnostic trouble ccde (DTC) 23, 34, 36, 44 or 45 are displayed.
Once erased, the code can be reproduced by starting the engine when cold and idling to normal operating temperature.
Incorrect air injection thermo-vacuum valve calibration can cause vacuum to be applied to the air diverter valve when the coolant temperature is above the normal switch-off temperature. Air can then be injected into the exhaust when the on-board diagnostic system is able to recognize excess oxygen and trigger a DTC code. There is no effect on driveability.
ACTION:
If DTC 23, 34, 36, 44 or 45 is encountered, check the air injection thermo-vacuum valve as follows:
^ Run the engine until the coolant reaches approximately 122~F (50~C). The temperature gauge will read just above "C".
^ Disconnect the air diverter valve hose from the thermo-vacuum valve port. Refer to Fig. 1A.
^ With the engine running, check for vacuum at the exposed thermo-vacuum valve port. No vacuum should exist.
^ If vacuum is does exist, replace the thermo-vacuum valve
(EBC 4599).
^ Re-test the vehicle by starting the engine when cold and idling to normal operating temperature.
PARTS INFORMATION:
Part Number Description
EBC 4599 Thermo-vacuum valve
WARRANTY INFORMATION:
Fault Code R.O. Number / Desc.- Time Allowance
1TCL 17.25.37 / Replace air 0.15 hrs.
injection thermo-vacuum valve