P0299

120308 - P0299

Information saved in
DME

Fault code
120308 - P0299

Fault text
Charge-air pressure control, lower value: charge-air pressure
too low

Fault description
The diagnostic function monitors the pressure recorded at
the boost-pressure sensor and compares it with the specified
value.

Condition for fault identification
Test condition:
The fault is recognized when the monitored pressure is 90
hPa below the specified pressure while the wastegate's
pulse-duty factor is simultaneously too high.
Potential problem source(s):
- Boost-pressure sensor defective
- Vacuum converter for wastegate valve defective
- Wastegate valve is defective (seized in open position)
-
Terminal condition: none
Voltage condition:
- None
Temperature condition:
- None
Time condition:
- None
Other conditions:
- Engine speed > 1900 rpm
- A load must be applied to ensure that the turbocharger
boost will be within a specific closed-loop control range
(specified pressure ratio at compressor greater than 1.25 to
1.8 and less than 1.7 to 2.5, in both cases as characteristic
curve over engine rpm)

Condition for fault memory entry
This fault is logged in the control module's fault memory if
it remains present for longer than 1.6 sec.

Action in service
- Check vacuum at wastegate valve vacuum converter output
side (at idle -450 +/- 50 hPa at pulse-duty factor of 50%), for
testing see test module
- Check wastegate valve for stiction, see test module
- Check vacuum at input to wastegate valve vacuum
converter (-900 to -800 hPa is specified)

Fault effect and breakdown warning
Breakdown notice:
- The engine reverts to its limp-home program, continued
vehicle operation is possible but drivability is restricted,
because power is reduced the driver should refrain from
passing maneuvers.
Possible apparent symptoms:
- Reduced power

Driver information
Warning light:
- ECE emissions warning lamp: off
- US emissions warning lamp: off
- ECE electronic engine power reduction: on
- US electronic engine power reduction: on
- CC message: none

Service instruction
- none