|
No.
|
TECH 1 Display
|
Conditions for
Checking
|
Nominal Value
|
Trouble Codes
|
Terminal
|
|
18
|
O2 SENSOR
|
Ignition ON
Engine cold!
Engine running at idle speed,
operating temperature
|
350 to 550 mV
50 to 950 mV alternating
|
13,44,45
|
B
11/B 10
|
|
Trouble-shooting:
|
Nominal Value:
|
Cause of
Fault:
(If nominal
value is not attained)
|
|
· Disconnect wiring harness
plug from oxygen sensor
· Measure voltage:
from: wiring harness plug P 33
to: ground
· Ignition ON
|
300 to 550 mV
|
· Lead interruption
from: wiring harness plug P 33
to: control unit K 57/K 91 Ter. B 11
· Lead interruption
from: control unit K 57/K 91 Ter. B 10
to: ground
(with display 800 to 1000 mV)
· Short circuit in wiring
harness
from: control unit K 57/K 91 Ter. B 1
to: ground
· Control unit defective
|
|
· Engine in TECH 1 mode
"F8" submode "F0".
Using arrow keys, set to 1300 rpm
· Measure voltage:
from: oxygen sensor plug
to: ground
(oxygen sensor plug disconnected)
|
50 to 950 mV
|
· Oxygen sensor defective
|
|
· Accelerate briefly
|
when
accelerating greater
than 700 mV
|
· Mixture constantly too
lean/rich
(see
overleaf)
· Check oxygen sensor (see
below)
|
|
· Check oxygen sensor:
|
|
|
|
· Using multimeter, measure
voltage:
from: oxygen sensor plug
to: oxygen sensor ground (thread)
|
greater than
22 kW
|
· Oxygen sensor defective
|
|
Part 2
Mixture
constantly too rich
(oxygen
sensor voltage greater than 600 mV)
|
|
|
|
· Check fuel pump
pressure feed pressure:
return
pressure:
|
approx. 3.0
bar (idle speed)
0.3 - 1.5 bar
|
· Return line
blocked/kinked
· Leaky injectors (injector
drips)
· Active carbon canister or
line to intake manifold leaky
· Active carbon canister -
valve defective
· Temperature sensor P 30
defective (see test step 03)
· Intake manifold pressure
sensor defective (see test step 05)
Intake manifold pressure sensor hose leaky, jams
· Throttle valve
potentiometer defective (see test step 06)
· Fuel pressure regulator
defective
|
|
If all nominal values are
attained:
· Internal exhaust gas
recirculation rate too large
|
|
· Check valve timing and
tightness
· Control unit defective
|
|
Part 3
Mixture
constantly too lean
(oxygen
sensor voltage less than 300 mV)
|
|
|
|
· Check fuel pump
pressure feed pressure:
return
pressure:
|
approx. 3.0
bar (idle speed)
0.3 - 1.5 bar
|
· Feed line blocked / kinked
· Injectors blocked or defective
· Connection line from air cleaner to
throttle body leaky
· Active carbon canister or line to
intake manifold leaky
· Intake manifold pressure sensor
defective (see test step 05)
Intake
manifold pressure sensor hose defective
· Temperature sensor P 30 defective (see
test step 03)
· Throttle valve
potentiometer defective (see test step 06)
· Fuel pressure regulator defective
· Intake system leaky
· Exhaust system leaky
· Poor fuel quality
· Control unit defective
|
|
|
|
|
|
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