2469 P1128 0-116 page 1
p1128
Printed in Germany – 4, 2002
0-116 P1128
360 Oxygen Sensing Adaptation, Idle Range, Bank 1 -
Below Limit
Diagnosis conditions
• Oxygen sensing system active
• Time elapsed after engine start-up: 250 to 350 seconds (USA)
• Time elapsed after engine start-up: 302 to 402 seconds (RoW)
• Engine temperature greater than 60 °C
Possible fault cause
♦ Incorrect signal from MAF sensor
♦ Fuel pressure too high
♦ Fuel injector leaking
♦ EVAP canister purge valve open
Affected terminals
-
Diagnosis/Troubleshooting
♦ If DTC P0445 (fuel tank vent valve - short to ground) is stored, correct this fault first. An open EVAP canister
purge valve can lead to the lean threshold being reached.
♦ For vehicles in the USA, the upper load range will probably not be reached. The only case in which a fault could
be stored is during driving while towing a trailer or caravan on a hill.
♦ Contrary adaptation values in connection with misfiring point to incorrectly adjusted control timescheck control
times and adjust if necessary.
♦ If the fuel tank reserve light is switched on, no fault is entered.
Work instruction Display OK If not OK
1 Check signal from MAF
sensor.
♦ Connect special tool 9637.
♦ Measure voltage at pin III/23
and ground
♦ Switch on the ignition.
0.9 to 1.1 V. Replace MAF sensor
♦ Start the engine. Approx. 1,4 V
2 Check fuel pressure
Note!
DME 7.8 DME 7.8
2469 P1128 0-116 page 2
p1128
0
Printed in Germany – 4, 2002
360 Oxygen Sensing Adaptation, Idle Range, Bank 1 -
Above Limit
Diagnosis conditions
• Oxygen sensing system active
• Time elapsed after engine start-up: 250 to 350 seconds (USA)
• Time elapsed after engine start-up: 302 to 402 seconds (RoW)
• Engine temperature greater than 60 °C
Possible fault cause
♦ Incorrect signal from MAF sensor
♦ Intake air system leaking
♦ Fuel pressure too low
♦ Volume supply of fuel pump too low
♦ Fuel injectors fouled
3 Check fuel pressure regulator,
vacuum connection
and fuel return line
♦ Remove vacuum hose from fuel
pressure regulator
♦ Connect special tool 9103/2 to
vacuum hose
♦ Start the engine.
♦
0.4 - 0.6 bar Check the intake air
system for leaks
and check vacuum
line to fuel pressure
regulator for restrictions.
♦ Check housing of fuel pressure
regulator for damage and deformation
Replace the fuel
pressure regulator if
it is damaged with
the result that the
spring pre-tensioning
is increased
4 Check EVAP canister
purge valve
♦ Disconnect hose from EVAP canister
purge valve to intake system
at EVAP canister purge
valve
♦ Remove connector of EVAP canister
purge valve
♦ Connect special tool 9160/1 to
EVAP canister purge valve
♦ Generate vacuum of approx. 0.7
bar
The vacuum must
not fall below 0 bar
after 10 minutes
5 Check fuel injectors for
leaks
Work instruction Display OK If not OK
DME 7.8
2469 P1128 0-116 page 3
DME 7.8
p1128
0
Printed in Germany – 4, 2002
♦ PCV valve leaks
♦ Cap of oil filler neck not closed correctly or seal is damaged
Affected terminals
-
Diagnosis/Troubleshooting
♦ Air leaks ahead of the oxygen sensors can lead to a fault in adaptation Check exhaust system for leaks.
♦ Contrary adaptation values in connection with misfiring point to incorrectly adjusted control timescheck control
times and adjust if necessary.
♦ If the fuel tank reserve light is switched on, no fault is entered.
Work instruction Display OK If not OK
1 Close cap of oil filler neck
properly or replace the
seal
2 Check signal from MAF
sensor.
♦ Connect special tool 9637.
♦ Measure voltage at pin III/23
and ground
♦ Switch on the ignition.
0.9 to 1.1 V. Replace MAF sensor
♦ Start the engine. Approx. 1,4 V
3 Check exhaust system for
leaks
4 Check for air leaks in
intake air system
5 Check PCV valve for leaks
6 Check fuel pressure
7 Check volume supply of
fuel pump
8 Fuel injectors fouled ♦ If preceding Check Points were
negative, the fuel injectors may
be fouled
♦ Clean fuel injectors (ultrasonic
cleaning device) or replace them
Note!