Fault Code Guide

sumes full recirculation mode for 20 minutes.
This cycle repeats as long as the system re-
mains in recirculation mode.
The control head senses the recirculation door posi-
tion by reading the feedback voltage from the actua-
tor position sensor. The feedback voltage will be less
than the 5V reference voltage sent by the control
head to the sensor.
The target position is based on the recirculation but-
ton setting and internal control head algorithms. The
desired position is considered reached when one of
the following conditions is true, although this does
not necessarily mean that the position actually corre-
sponds to the desired recirculation button setting (for
example, if the actuator movement is limited due to
an obstruction).
• The actuator feedback position has been
reached.
• The actuator is stalled for more than 1 second;
the actuator feedback position does not
change for more than 1 second.
• The target position corresponds to an end stop
and an additional 1 second extra drive in the
same direction (to guarantee sealing) has been
performed.
The recirculation door should move from one ex-
treme position to the other when the recirculation
button is pressed on and then pressed off.
Perform the tests in Table 5 in the sequence pre-
sented. The directions under the column "What to Do
if Test Fails" are sometimes dependent on good re-
sults from previous tests. If any of the tests fail, stop
and perform the specified repair or check. If the recir-
culation door actuator passes the tests in Table 5
and the actuator still does not operate properly,
check for mechanical problems with the actuator. To
quickly check for normal operation, set the fan switch
to high and listen for a change in the sound of the
blower near the HVAC unit while pressing the recir-
culation button on and off. The blower will be louder
when recirculation is enabled.
Recirculation Door Actuator Circuit Tests
Test Conditions Test Point
Good
Result
What to Do if Test Fails
actuator motor
drive circuit
key on, engine off
recirculation door actuator
connector removed
fan (blower) speed on low
change the recirculation setting
while observing the digital
multimeter (DMM)
Measure across pins 5 and 6
of the recirculation door
actuator connector.
9V+ for
about 1
second
*
Check wiring between control
head and recirculation door
actuator.
If wiring is okay, replace the
control head.
actuator
position sensor
reference
voltage circuit
key on, engine off
recirculation door actuator
connector removed
Measure between pin 10 of
the recirculation door
actuator connector and the
battery negative post.
5V
actuator
position sensor
reference
ground circuit
key on, engine off
recirculation door actuator
connector removed
Measure between pin 8 of
the recirculation door
actuator connector and the
battery positive post.
12V
*
Cab Heater and Air Conditioner, Valeo 83.00
Troubleshooting
Business Class M2 Workshop Manual, Supplement 13, March 2008 300/11