Group 87 Climate Control, Fault Codes
Troubleshooting
MID 146 SID 22 Pressure Sensor, Refrigerant
W8003237
T8009496
Component: A34 Climate Control Unit, E32 Climate
Unit
General information
The sensor measures pressure in the air conditioning
(A/C) system. The pressure signal is used to activate
the engine cooling fan. The sensor is located on the
pressure line between the drier / refrigerant reservoir and
the expansion valve. A high pressure at the sensor may
be caused by a blocked expansion valve. Low pressure at
the sensor may be caused by a blocked drier / refrigerant
reservoir or loss of refrigerant.
Fault code
FMI 3
Abnormally high voltage or short-circuit to higher voltage.
Conditions for fault code:
•
If the control unit receives a signal from the sensor that
is higher than 4.5V the control unit interprets this as an
error and a fault code is stored
Possible cause:
•
Signal cable short-circuited to higher voltage
•
Ground lead short-circuited to higher voltage
•
A blocked expansion valve may cause a high voltage
or pressure reading
Reaction from the control unit:
•
Fault code is stored
•
Yellow lamp requested
Noticeable external symptoms:
•
Yellow lamp lights up
•
No cooling effect
Appropriate check:
•
See “MID 146 SID 22 Pressure Sensor Refrigerant
High Pressure Side, Check ” page 38
FMI 4
Abnormally low voltage or short-circuit to lower voltage
Conditions for fault code:
•
If the control unit receives a signal from the sensor that
is lower than 0.3V the control unit interprets this as an
error and an fault code is stored
Possible cause:
•
Signal cable short-circuited to ground / sensor ground
•
A blocked reciever drier may cause a low voltage or
pressure reading.
•
An expansion valve that is stuck open could also cause
a low voltage reading to occur.
Reaction from the control unit:
•
Fault code is stored
•
Yellow lamp requested
Noticeable external symptoms:
•
Yellow lamp lights up
•
No cooling effect
Appropriate check:
•
See “MID 146 SID 22 Pressure Sensor Refrigerant
High Pressure Side, Check ” page 38
37