System Diagnostics - Chrysler Town and Country 2003 Owner's Manual

GENERAL INFORMATION
CAUTION: Automatic Temperature Control
(ATC) Modules with software versions 41 and
0A used in 2001 and 2002 RS/RG vehicles are
NOT compatible with software versions 13
and 0F used in 2003 RS/RG vehicles. Do NOT
install an ATC Module with software version
41 or 0A in a 2003 RS/RG vehicle or an ATC
Module with software version 13 or 0F in a
2001 or 2002 RS/RG vehicle. Use the DRBIII
to verify which version software the ATC
Module is using by selecting Body Systems,
Automatic Temperature Control, and then
selecting Module Display.
• a Two-Zone HVAC system on select models.
•
a Cabin Heater used in conjunction with the ATC
system. For additional information on this sys-
tem, refer to The AC Cooldown Test, under 3.9.1.4
System Diagnostics in this General Information
section, and refer to Cabin Heater under General
Information and Diagnostic Procedures in this
manual.
• deletion of the rear IR sensor.

3.9.1.4 SYSTEM DIAGNOSTICS

Fault detection is through active and stored Diag-
nostic Trouble Codes (DTCs)
• DTCs are displayed by the DRBIII .
• Active DTCs are those which currently exist in
the system. The condition causing the fault must
be repaired in order to clear this type of DTC.
• Stored DTCs are those which occurred in the
system since the ATC Module received the last
clear diagnostic info message.
The AC Cooldown Test:
• is actuated with the DRBIII .
• checks A/C system performance based on evapo-
rator temperature sensor input.
• forces the ATC to initiate the Cabin Heater Acti-
vation request when the vehicle is equipped with
a Diesel Cabin Heater Assist.
WARNING: DO NOT OPERATE THE DCHA IN
AN ENCLOSED AREA SUCH AS A GARAGE
THAT DOES NOT
VENTILATION FACILITIES. ALWAYS VENT
THE DCHA's EXHAUST WHEN OPERATING
THE DCHA. REFER TO VENTING THE
DCHA's EXHAUST UNDER CABIN HEATER IN
THE GENERAL INFORMATION PORTION OF
THIS SECTION FOR PROPER EXHAUST
VENTING INSTRUCTIONS.
FOLLOW THESE
RESULT IN PERSONAL INJURY OR DEATH.
HAVE EXHAUST
FAILURE TO
INSTRUCTIONS MAY
CAUTION: Do not activate the A/C Cooldown
Test with the engine off. Failure to follow
these instructions may result in internal
damage to the DCHA Heater Module.
The FCM monitors the PCI bus for the Cabin
Heater Activation request. The request car-
ries the status bit that the FCM requires to
activate its' Cabin Heater Assist Control out-
put. This output is a low side driver (coming
from FCM pin 15) which supplies a ground
signal to the Cabin Heater (pin 5). When the
Cabin Heater receives this ground signal in-
put, it interprets this as an activation signal.
The FCM low side driver is also capable of
diagnostic sensing. The driver will sense an
open circuit when the driver is off, and will
sense a short to voltage when the driver is on.
The FCM will set DTCs for both of these types
of faults. For additional information, refer to
Cabin Heater under General Information and
Diagnostic Procedures in the manual.
• will not run the air conditioning portion of this
test if ambient temperature is below 12°C (53°F).
The forced Cabin Heater activation will occur
even if the air conditioning portion of this test
fails to initiate because AC Cooldown test
criteria was not met. When activated, the
DCHA will operate for approximately seven
minutes. Three minutes to run and four min-
utes to purge.
• will pass the air conditioning portion of this test
if the evaporator temperature drops 6.7°C (20°F)
within two minutes of starting this test.
• messages (air conditioning related only) display
on the DRBIII after running this test.
These messages will clear after paging back
out of this test. Therefore, it is important to
note all of the AC Cooldown test messages
before doing so.
All Cabin Heater-related DTCs display under
Cabin Heater, Read DTCs.
• will cause the DELAY and Snowflake VF seg-
ments on the ATC to flash for 162 seconds (RG
with DCHA only). If the air conditioning portion
of this test fails, the DELAY and Snowflake VF
segments will continue to flash until the vehicle
is driven more than three miles.
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