P1115
P1115
Oxygen sensor heating 1 ahead of catalytic converter - below lower threshold.
P1119
Oxygen sensor heating 2 ahead of catalytic converter - below lower threshold.
Function:
The oxygen sensor generates a voltage signal at approximately 300°C that determines the fuel/air mixture. This signal is used for the regulation of the fuel injection. The oxygen sensor is heated to bring it quickly to operating temperature to start oxygen sensing earlier.
Diagnosis Conditions:
During a cold start (sensor readiness after 20 seconds) the time ti is measured. t1 is the time from switching the oxygen sensor heating on until the time an oxygen sensor is operational. Then a time t2 is calculated (t2=2.5*t1). t3 is the time from switching the oxygen sensor heating on until the time the other oxygen sensor is operational. When t3 is larger than t2 a fault is recognized.
When a fault is recognized, the resistance comparison of the oxygen sensor heating is blocked. If no fault is recorded, the calculated resistance of the oxygen sensor heating is compared to a threshold after 400 seconds. If the resistance is too high, a fault is recognized for both oxygen sensor heatings.
NOTE: Heating of oxygen sensors (1 and 2) ahead of catalytic converters is supplied by a final stage. It may occur that both heating circuits are stored in memory as faulty although only one heating circuit is actually faulty. If a sensor signal fault is stored in addition, this fault must be remedied first. Then road-test the car or perform short test. When all the four heating circuits are stored in memory as faulty, check common plus supply.
Oxygen sensor 1 - cylinders 1 to 3
Oxygen sensor 2 - cylinders 4 to 6
Connector color grey - behind catalytic converter
Connector colour black - ahead of catalytic converter
Wiring Diagram:
Image Legend:
A. Ignition, injection and oxygen sensor heating relay
Diagnostic Procedure:
1. Check resistance of oxygen sensor heating.
1. Remove connector of oxygen sensor 1/2 ahead of catalytic converter.
2. Connect ohmmeter on pin side to pins 1 and 2.
Specified Value: 1.8 - 2.5 Ohms at 20°C.
3. Connect ohmmeter on pin side to pin 1 and the oxygen sensor housing.
Specified Value: Infinity Ohms.
2. Check wiring from ECM to disconnect oxygen sensor 1/2 for continuity, short circuit to plus and short circuit to ground.
1. Remove connector for oxygen sensors 1 and 2 ahead of catalytic converter.
2. Connect special tool 9616 to wiring harness.
3. Connect ohmmeter to special tool 9616 pin 30 and disconnection of oxygen sensors 1/2 ahead of catalytic converter pin 2.
Specified Value: < 1 Ohms.
4. Connect ohmmeter at sleeve to connector, pin 2, and ground.
Specified Value: Infinity Ohms.
5. Remove ignition, injection and oxygen sensor heating relay and bridge terminals 30 and 87.
6. Connect voltmeter at sleeve to connector, pin 2, and ground.
Specified Value: 0 Volt.
3. Check ECM final stage.
1. Remove connectors for oxygen sensors.
2. Start engine and run engine at high speed for three minutes.
3. Connect voltmeter at sleeve to pins 1 (plus) and 2.
Specified Value: battery voltage.