DTC P1194: Heated Oxygen Sensor (Ho2S) 1 Or 2 Heater Fault

NOTE: After each repair, clear DTCs. See CLEARING CODES/PCM RESET PROCEDURE under SELF-DIAGNOSTIC SYSTEM. Turn ignition off and then on. Read DTCs to verify repair is complete. For DLC and PCM connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagrams, see WIRING DIAGRAMS .

NOTE: On 1995 models: HO2S 1 is located downstream of pre-catalytic converter for cylinders No. 1, 2 and 3. HO2S 2 is located downstream of pre-catalytic converter for cylinders No. 4, 5 and 6. HO2S 3 is located upstream of pre-catalytic converter for cylinders No. 1, 2 and 3. HO2S 4 is located upstream of pre-catalytic converter for cylinders No. 4, 5 and 6. On XJ6, HO2S 3 and 4 apply to Federal vehicles only.

NOTE: On 1996-1997 models: There are 2 HO2S "A", one upstream of the pre-catalytic converter and one downstream of the pre-catalytic converter, for cylinders No. 1, 2 and 3. There are 2 HO2S "B", one upstream of the pre-catalytic converter and one downstream of the pre-catalytic converter, for cylinders No. 4, 5 and 6.

Using scan tool, read DTCs. If DTC P1194 is present, turn ignition off. Ensure HO2S harness and connectors are not damaged and connections are okay. Repair as necessary. If harness and connectors are okay, go to next step.
Disconnect both downstream pre-catalytic converter HO2S (No. 1 and 2) HO2S harness connectors. Using DVOM, check resistance across each HO2S terminals No. 3 and 4. Resistance should be 10-20 ohms with temperature at -5 to 212°F (-20 to 100°C). If resistance is not within specification, replace HO2S. If resistance is within specification, go to next step.
Check for continuity of Blue/Pink wire between No. 1 and No. 2 HO2S connector terminals No. 3, and between No. 1 HO2S connector terminal No. 3 and PCM Black connector terminal No. 4. On XJR and XJ6, check for continuity of White/Green wire between No. 1 and No. 2 HO2S connector terminals No. 4 and fuse No. 14 (10-amp), located in fuse box at right front of engine compartment. On XJS, check for continuity of White/Brown wire between No. 1 and No. 2 HO2S connector terminals No. 4 and fuel pump relay, located above right rear wheelwell. On all models, repair wiring as necessary. If wiring is okay, go to next step.
Check Blue/Pink wire for short circuit to ground between No. 2 HO2S connector terminal No. 3 and ground. Repair wire as necessary. If wire is okay, reconnect HO2S harness connectors. Clear DTCs. Turn ignition off and then on. Read DTCs. If DTC P1194 is not present, repair is complete. If DTC P1194 is present, replace PCM.