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SUB-FUNCTION: COLD LOOP (CONTINUED 1)
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine at idle speed, AIR CONDITIONING OPERATING
(air conditioning compressor engaged).
ComputerParameter or Status
checked or ActionDisplay and Notes Fault finding
Injection
(see 13B, Diesel
injection or 17B,
Petrol injection)ET079:Air conditioning
presentYES
(automatic injection
computer configuration)If the status displays NO, refer
to the interpretation of this
status.
ET088:Compressor
actuation
requestACTIVEIf the status displays INACTIVE,
refer to the interpretation of this
status.
ET004:Air conditioning
authorisationYESIf the status displays NO, refer
to the interpretation of this
status.
PR037:Refrigerant
pressure1 bar < X < 27 barIn the event of a fault, see the
interpretation of this
parameter.
PR055:Engine speed800 rpm ± 50 rpmIn the event of a fault, see the
interpretation of this
parameter.
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SUB-FUNCTION: COLD LOOP (CONTINUED 2)
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine at idle speed, AIR CONDITIONING OPERATING
(air conditioning compressor engaged).
ComputerParameter or Status
checked or ActionDisplay and Notes Fault finding
Injection
(continued 1)
(see 13B, Diesel
injection or 17B,
Petrol injection)ET023:Fast idle speed
requestPRESENTIn the event of a fault, refer to the
interpretation of this status.
PR064:Coolant
temperatureX = engine coolant
temperatureIn the event of a fault, see the
interpretation of this
parameter.
PR089:Vehicle speed0 mphIn the event of a fault, see the
interpretation of this
parameter.
PR125:Power absorbed
by the air
conditioning
compressor300 W < X < 5000 W
(ambient temperature
23 ˚C)In the event of a fault, see the
interpretation of this
parameter.
ET022:Low speed fan
assembly
requestACTIVE if the refrigerant
fluid pressure is less
than 19 bar, and
INACTIVE otherwiseIn the event of a fault, refer to the
interpretation of this status.
ET021:High speed fan
assembly
requestACTIVE if the refrigerant
fluid pressure is greater
than 19 bar, INACTIVE
otherwise.In the event of a fault, refer to the
interpretation of this status.
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SUB-FUNCTION: HEATING
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine at idle speed, AIR CONDITIONING OPERATING
(air conditioning compressor engaged).
ComputerParameter or Status
checked or ActionDisplay and Notes Fault finding
UCH (continued)
(see 87B,
Passenger
compartment
connection unit)ET239:Ignition switch
position+ after ignition feedIn the event of a fault, refer to the
interpretation of this status.
PR025:Engine speed800 rpm ± 50 rpmIn the event of a fault, see the
interpretation of this
parameter.
PR024:Engine coolant
temperatureX = engine coolant
temperatureIn the event of a fault, see the
interpretation of this
parameter.
ET015:Passenger
compartment
blowerACTIVE
(according to test
conditions: see Notes).In the event of a fault, refer to the
interpretation of this status.
Note: This status only operates
for manual air conditioning and
heating versions.
PR001:Battery voltage12.5 V < X < 14.4 VIn the event of a fault, see the
interpretation of this
parameter.
If the fault is still present, carry
out fault finding on the charging
circuit (see MR 411 Mechanical,
16A, Starting - Charging).
PR002:Exterior
temperature
(depending on
the version)X = exterior
temperature ±± ± ±
5 ˚C
(invalid value: 215 ˚C).In the event of a fault, see the
interpretation of this
parameter.
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SUB-FUNCTION: HEATING
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine at idle speed, AIR CONDITIONING OPERATING
(air conditioning compressor engaged).
ComputerParameter or Status
checked or ActionDisplay and Notes Fault finding
Injection (see 13B,
Diesel injection or
17B, Petrol
injection)PR064:Coolant
temperatureX = engine coolant
temperatureIn the event of a fault, see the
interpretation of this
parameter.
ET111:RCH number setYES or NO
Note: Depending on the
requirements of the
injection system (power
requirement, torque
reduction, etc.), the
injection computer sets
the controlled
passenger compartment
heating resistor stage
number (no more,
no less)In the event of a fault, refer to the
interpretation of this status.
ET112:RCH cut-offYES or NO
Note: Depending on the
requirements of the
injection system (power
requirement, torque
reduction, etc.), the
injection computer sets
the controlled
passenger compartment
heating resistor stage
number (no more,
no less)In the event of a fault, refer to the
interpretation of this status.
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SUB-FUNCTION: USER SELECTION
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine at idle speed, AIR CONDITIONING OPERATING
(air conditioning compressor engaged).
ComputerParameter or Status
checked or ActionDisplay and Notes Fault finding
UCH (see 87B,
Passenger
compartment
connection unit)ET028:Heated rear
screen buttonPRESSED if the heated
rear screen key on the
air conditioning control
panel is pressed.
RELEASED otherwise.In the event of a fault, refer to the
interpretation of this status.
ET029:Air conditioning
buttonPRESSED if the AC
button on the air
conditioning control
panel is pressed.In the event of a fault, refer to the
interpretation of this status.
ET015:Passenger
compartment
blowerACTIVE
(according to test
conditions: see Notes).In the event of a fault, refer to the
interpretation of this status.
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ALP 8
CONTINUED 1
1
Using the diagnostic tool statuses and parameters
screen (UCH heating sub-function), check that the
temperature signals are consistent (no sensor
deviations resulting in incorrect measurement).
–Use statuses PR002 Exterior temperature and
PR024 Engine coolant temperature.
Are the temperature signals consistent?
YES
Start the engine and switch on the air conditioning by
pressing the AC button (with a request for maximum
cold temperature and the passenger compartment
blower running).
2
Display the following status in the “User selection”
sub-function screen:
ET029 Air conditioning button should be
PRESSED.
Note:
The status indicates if the signal for the AC button
pressed on the control panel is read by the UCH
correctly.
Does status ET029 display PRESSED?
YES
NOCarry out a conformity check:
–For the coolant temperature sensor,
see 13B, Diesel injection, Fault
summary table or 17B Petrol
injection, Fault summary table.
–For the exterior temperature sensor,
see 87B, Passenger compartment
connection unit, Fault summary
table.
Replace any faulty components.
NOContinuity fault on connection 38LP.
Using an ohmmeter, carry out a continuity
test on connection 38LP between
components 319 and 645. If there is a
procedure (see Technical Note 6015A,
Repairing electrical wiring, Wiring:
Precautions for repair), repair the wiring,
otherwise replace the wiring.
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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ALP 8
CONTINUED 2
With the engine running at idle speed, use the
diagnostic tool to check that UCH does in fact
send the start air conditioning request to the
injection computer. Status ET030 Air conditioning
request 2 should display ACTIVE.
Is status ET030 “ACTIVE”?
YES
Using the diagnostic tool (injection cold loop sub-
function screen), display the following statuses:
- ET004 Air conditioning authorised,
- ET088 Compressor activation request.
Is status ET004 “YES” and status ET088
“ACTIVE”
NO
Check that the injection computer is correctly configured. Status ET079 CLIMATE CONTROL PRESENT should
display YES (cold loop sub-function screen).
Is status ET079 YES?
YESNOCheck that the UCH is correctly configured by
viewing the configuration reading LC013 Type
of air conditioning.
Should be “Manual air conditioning”
Reconfigure the UCH if necessary.
Check that the UCH is receiving the engine
operating status and passenger compartment
blower signals correctly (for manual air
conditioning). In the Cold Loop sub-function
screen, status ET142 “Engine operating
phase” should display “RUNNING” and status
ET015 “Passenger compartment blower”
should display “ACTIVE” and parameter
PR024 “Exterior temperature” should be >
3˚C.
If the parameter and statuses are not correct,
carry out fault finding on the multiplex network
and UCH (interpretation of status ET015,
ET142 and parameter PR024).
YES
NO
Interpretation fault for status ET079, see
conformity check, cold loop sub-function:
–13B, Diesel injection,
–17B, Petrol injection.
AFTER REPAIRCarry out a complete check with the diagnostic tool.
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ALP 8
CONTINUED 3
Carry out fault finding on the injection system to ensure that no fault is present (if faults are displayed by the
injection computer, engagement of the air conditioning may be inhibited). If there are present or stored faults,
carry out the necessary repairs (see 13B, Diesel injection or 17B, Petrol injection).
Check that the refrigerant fluid pressure is correct (neither too low nor too high) using the PR037 Refrigerant
fluid pressure parameter (see Conformity check, Cold loop sub-function).
Check that the engine cooling fan assembly is at
speed 1 by viewing the following status on the cold
loop sub-function screen:
–Status ET022 Low-speed fan assembly request
should display ACTIVE.
Note:
These statuses are not displayed by all types of
injection (see Conformity check, Cold loop sub-
function).
Does the engine cooling fan operate at low speed?
YES
NOUsing the diagnostic tool, run
command AC154 Low speed fan
assembly relay.
Does the engine cooling fan operate
at low speed?
NO YES
Connector of component 321 disconnected. Connect a
test light between connection 49L of component 321
and the chassis earth and run command AC154 Low
speed fan assembly relay.
Does the test light illuminate?
YES NO
Measure the resistance of component 321, between
connections 49L and 49B of component 321. If the
resistance measured is infinite, replace the fan assembly
resistor (component 321).
Carry out fault
finding on the
injection system
(sub-function: cold
loop and engine
cooling for low
speed fan assembly
activation).
D
AFTER REPAIRCarry out a complete check with the diagnostic tool.