High Fuel Consumption

High fuel consumption


Fault symptom
High fuel consumption, engine rough


Conditions
No diagnostic trouble code.


Diagnostic procedure




1 Check fuel enrichment (LH 2.4.2)
For LH system 2.4.2 (for other LH Systems continue with point 2).
- Select command code 206 (on the LH system) while the car is being driven.
- Check whether fuel enrichment occurs continuously (8B006 or 8B106 constantly).
- The enrichment signal should be activated the whole time and no knocking/pinking should occur.
Under normal conditions, it should alternate between 8B006 and 8B106.

Working OK?
YES Continue with point 3.
NO If the signal is high, continue fault diagnosis as described under "Diagnostic trouble codes 44661/24661" (knock sensor).




2 Check fuel enrichment (LH 2.2, 2.4)
- Take voltage readings on pin 26 of the DI/APC control module.
PRE-IGNition enrichment 0 V
No enrichment 6.5 V
Knocking enrichment B+

Are the voltage readings correct?
YES Continue with point 3.
NO Continue fault diagnosis as described under "Diagnostic trouble codes 44661/24661" (knock sensor).

3 Check the knock sensor's signal level
- Check whether the knock sensor has a high signal level.
- Select command code 329 (-M90) or 229 (M91-) on the DI/APC system.
- Command code 283 can also be used on M91 and later models.

Is the signal high?
YES Continue fault diagnosis as described under "Diagnostic trouble codes 44661/24661" (knock sensor).
NO Continue fault diagnosis of the LH system. Description of On-Board Diagnostics