LI07.04-P-059726

Engine diagnosis warning lamp (CEL) is active due to fault codes - P2237 & P2626.
Topic number
LI07.04-P-059726
Version
5
Design group
07.04 Senders, sensors
Date
07-15-2016
Validity
Model 451.331 or 451.431
Reason for change
Remedy revised.
Reason for block
Complaint:
Engine diagnosis warning lamp is active with no drivability complaint. A fault relating to the oxygen sensor (G3/2) is
stored in the engine control unit. Fault Code P2237 "The pump current connection of oxygen sensor 1 (cylinder bank
1) has an electrical fault or open circuit. Fault Code P2626 "The trimming resistor connection of oxygen sensor 1 (cylinder bank 1) has an electrical fault or open circuit. Possibly fault P0410 could be encountered as well.
Cause:
Cause can be attributed to transitional - or contact resistance - at O2 sensors connector pins.
Remedy:
If P0410 is encountered, please process fault code following Xentry/DAS guided tests first.
1. Perform guided tests-->exhaust system-->"test of secondary air injection"
2. If step 1 fails, please perform repair to secondary air system.
3. Validate repair with two test drives letting the vehicle to return to ambient temperature (engine cold) between test
drives.
4. If no DTC P0410 is present, release the vehicle
5. If DTC P0410 reappears:
a. Start engine and verify vacuum is present to/from changeover valve Y32 before and after actuating valve Y32 with
Xentry/DAS.
b. Shut off engine
c. Disconnect metal pipe between exhaust manifold and secondary air valve (see AR14.30-P-7150MCU)
d. Turn the key ON
e. Actuate M33 electric air pump
f. Verify no air exits secondary air valve
g. Using a hand held vacuum pump, apply vacuum to secondary air valve and verify with M33 (electric air pump) actuated air flows freely from valve
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DOKONIE
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h. If any of the above steps fail, replace faulty component.
i. If no faulty component is found, proceed as indicated below.
If vehicle does not exhibit P0410, but has either P2237 or P2626, please perform the following:
•
•
•
•
Follow Xentry guided test to determine possible root cause related to P2237 or P2626
If guided test in the step above does not reveal root cause, disconnect the ME and O2 sensor connectors and
visually inspect pins (no drag test) for any damage, corrosion or pin spreading. If nothing obvious observed, reconnect connector plugs and follow with the step below
Inspect wiring harness for possible damages (refer to illustration in attachments), if visible damage noticed, replace the engine harness (follow the QEC return rule). If no damages observed follow with step below
If nothing found on either of the fault codes P2237 or P2626 follow with the replacemet of O2 sensor pins on the
the engine harness (refer to parts information for pin number and seal). Use the crimping tool 220 589 04 99 11
and refer to WIS documents relating to repairing wiring harness / disconnecting pins (listed in WIS references table).
The PTSS case should only be open in a situation when fault code(s) and the CEL come back and above steps were
already performed.
Attachments
File
Description
M132-smart 451 engine harness damage.pdf
Harness damage illustration
Symptoms
Power generation / Engine management / Indicator lamp / Engine diagnosis / lit
Control unit/fault code
Control unit
Fault code
Fault text
N3/10 (ME-SFI [ME] control
unit) (ME7_451)
P2237
The pump current connection of oxygen sensor 1 (cylinder
bank 1) has an electrical fault or open circuit. ((CODECO@494)
or(CODECO@460))
N3/10 (ME-SFI [ME] control
unit) (ME7_451)
P2626
The trimming resistor connection of oxygen sensor 1 (cylinder
bank 1) has an electrical fault or open circuit. ((CODECO@494)
or(CODECO@460))
N3/10 (ME-SFI [ME] control
unit) (ME7_451)
P0410
The secondary air system is faulty. ((CODECO@494)
or(CODECO@460))
Parts
Part number
ES1 ES2 Designation
Quantity Note
EPC
A 021 545 13 26
MCP1.2 female contact pin
1
X
A 000 545 69 80
wire seal
1
X
Operation numbers/damage codes
Op. no.
Operation text
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© Copyright Daimler AG
Time
DOKONIE
Damage
code
Note
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54575 52
Control unit, gasoline engine
14212 73
Oxygen sensor upstream of catalytic
convertor
WIS-References
Document number
Title
Note
Allocation
AR07.08-P-7008MCU
Remove/install injection system contr unit
AR07.04-P-0080MCV
Remove/install O2 sensor
AR54.21-P-0012MCU
Control unit flashing
Remedy
AR14.30-P-7150MCU
Remove/Install pipework for if applicable
secondary air system
Remedy
AR00.19-P-0100A
General repair methods for
wiring harness
Remedy
AR00.19-P-0120A
Removing contacts from
plugs and connectors
Remedy
Remedy
If applicable
Remedy
Validity
Vehicle
Engine
Transmission
fortwo 451 - 451.331
*
*
fortwo 451 - 451.431
*
*
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