|
No.
|
TECH 1 Display
|
Conditions for
Checking
|
Nominal Value
|
Trouble Codes
|
Terminal
|
|
10
|
O2 SENSOR
|
Ignition ON
Engine cold
|
350 to 550 mV
|
13, 44, 45
|
B 11 /
B 10
|
|
|
|
Engine running at idle speed, operating temperature
|
50 to 950 mV
alternating
|
|
|
|
Trouble - shooting:
|
Nominal Value:
|
Cause of Fault:
(If nominal value is not attained)
|
|
Part 1
· Disconnect
wiring harness plug from oxygen sensor.
· Measure
voltage:
from: wiring
harness plug P 33, wiring harness side
to: battery -
· Ignition
ON.
|
450 mV± 20 mV
|
· Lead
interruption
from: wiring
harness plug P 33
to: control
unit K 57 Ter. B 11
· Short
circuit in wiring harness
from: control
unit K 57 Ter. B 11
to: ground
(display less than 100 mV)
· Lead
interruption
from: control
unit K 57 Ter. B 10
to: ground
(display of 800 to 1000 mV)
· Short
circuit in wiring harness
from: control
unit K 57 Ter. B 11
to: battery +
(display greater than 1000 mV)
· Control
unit defective.
|
|
· Measure
voltage:
from: wiring
harness plug P 33, wiring
harness side
to: grounding
point on valve cover (old fastening point for fuel pump)
|
450 mV ± 20 mV
|
· Transfer
resistance at grounding point too high / large (clean battery lug, stud
and fastening nut)
· Control
unit defective.
|
|
· Engine
in TECH 1 mode "F6". submode "F0".
Using arrow keys, set at 1300 rpm.
· Measure
voltage:
from: oxygen
sensor plug P 33
to: ground
(oxygen sensor plug disconnected)
|
50 to 950 mV
|
· Oxygen
sensor defective
|
|
· Accelerate
briefly.
|
greater than 700 mV
|
· Mixture
constantly too lean / rich. (see overleaf)
· Oxygen
sensor defective
|
|
Part 2
Mixture constantly too rich
(Oxygen sensor voltage greater than 600 mV)
· Check
fuel pump pressure
|
|
|
|
Feed pressure:
|
approx. 0.75 bar (idle)
|
|
|
Return pressure:
|
approx. 0.3 bar
|
· Return
lead blocked / kinked
· Leaky
injector (drips)
· Controlled
canister purge system defective (see test step 22)
· Temperature
sensor P 30 defective (see test step 02)
· Intake
manifold pressure sensor P 23 defective (see test step 03)
· Intake
manifold pressure sensor hose leaky / jammed
· Throttle
valve potentiometer P 34 defective (see test step 04)
· Fuel
pressure regulator defective
· Incorrect
injector
|
|
If all nominal values are attained:
|
|
· Check
timing of valves and examine for leaks.
|
|
· Internal
exhaust gas recirculation rate too large.
|
|
· Control
unit defective
|
|
Part 3
Mixture constantly too lean
(Oxygen sensor voltage less than 300 mV)
|
|
|
|
· Check
fuel pump pressure
|
|
|
|
Feed pressure:
|
approx. 0.75 bar (idle)
|
|
|
Return pressure:
|
approx. 0.3 bar
|
· Feed
line blocked / kinked
· Injector
blocked or defective
· Connection
line from air cleaner to throttle body leaky
· Controlled
canister purge system defective (see test step 22)
· Intake
manifold pressure sensor P 23 defective (see test step 03)
· Intake
manifold pressure sensor hose defective
· Coolant
temperature sensor P 30 defective (see test step 02)
· Throttle
valve potentiometer P 34 defective (see test step 04)
· Fuel
pressure regulator defective
· Intake
system leaky
· Exhaust
system leaky
· Poor
fuel quality
· Incorrect
injector
· Control
unit defective
|
|
|
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