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P1102,P1115

P1102 , P1115

Preheating of front heated oxygen sensor

Fault symptoms

CHECK ENGINE lamp (MIL) on.

Conditions

P1102 Preheating current >2600 mA after 150 seconds.

P1115 Preheating current <600 mA after 150 seconds.

Diagnostic help

If the ISAT scan tool shows diagnostic trouble codes P1115 and P1117, the fault is probably due to:


- Preheating not working and fuse 38 having blown.

- The lead between pin 8 of H33-4 and pin 87 of the pump relay.


The preheating current can be ascertained with the ISAT scan tool.

Check the wiring

Intermittent faults may occur as a result of temporary short circuits and breaks in the wiring. Jiggle the wiring at several points and in different directions to ascertain whether the wiring harness, including any connectors, is causing the trouble. Observe the multimeter, ISAT scan tool or test lamp while doing this.

Diagnostic procedure

1. Check the fuses





Is fuse 38 intact?

yes

Continue with point 3.


no

Fit a new fuse. Continue with point 2.


2. Check the resistance of the oxygen sensor preheating elements


The engine should have been switched off for at least 5 minutes.


- Unplug the 4-pin connectors of both oxygen sensors.

- Take readings of the resistance of both sensors.


Are the readings OK?

yes

Check and if necessary repair or replace the leads between pin 1 of both oxygen sensor connectors and fuse 38. Continue with point 5.


no

Change the relevant oxygen sensor. Continue with point 5.


3. Check the preheating element power supply



- Unplug the oxygen sensor's 4-pin connector.

- Start the engine and run it at idling speed.

- Connect the test lamp to:


The test lamp should light up.

Did the test lamp light up?

yes

Continue with point 4.


no

Repair or replace the relevant lead. Continue with point 5.


4. Check the preheating circuit ground connection



- Connect the test lamp to:


The test lamp should flash or light up continuously.

Does the test lamp light up or flash?

yes

Change the sensor. Continue with point 5.


no

Check the relevant lead and repair or replace it if necessary. Continue with point 5.


5. Final check



- Clear the diagnostic trouble code.

- Implementation of driving cycle:

- Evaluation of driving cycle:


Has the diagnostic trouble code recurred?

yes

Continue as described in .


no

The steps taken to rectify the fault were correct.