Chrysler Pacifica. Manual - part 136

TEST

ACTION

APPLICABILITY

NOTE: Active DTCs must be resolved before diagnosing stored DTCs.
NOTE: Anytime a DTC becomes active or a Cooldown Test fault message is
displayed proceed to the conclusion question.
NOTE: If multiple DTCs appear, diagnose those that relate to a short circuit
first.
Start the engine.
Press the ATC’s PWR switch on.
Verify that the front blower motor operates correctly in all speeds. Diagnose and
repair all blower related faults before proceeding with this test.
CAUTION: The work area ambient temperature must be above 15.6°C (60°F)
and the evaporator temperature must be above 12°C (53°F) in order to test
A/C system operation.
NOTE: Before actuating the AC Cooldown Test, verify that the A/C compres-
sor is not running. If the compressor is running, turn the A/C off and allow
the evaporator to warm up before proceeding with the test.
NOTE: Running the AC Cooldown test will cause the DELAY & Snowflake
VF segments to flash. If the test fails, the DELAY & Snowflake VF segments
will continue to flash until the vehicle is driven more than 3 miles or a
successful Cooldown test is performed.
NOTE: Messages will display on the DRBIII

t after running the AC Cooldown

Test. These messages will clear after paging back out of this test function.
Therefore, it is important to note all messages before doing so.
With the DRBIII

t in ATC, System Tests, actuate the AC Cooldown test. If any

Cooldown Test fault messages appear, proceed to the conclusion question, otherwise,
proceed as follows:
Set the front blower speed to low.
Press the REAR fan mode switch on, so that it is in manual mode. The word

9REAR9

should display on the ATC display panel. The word

9AUTO9 should not be displayed.

Press the DUAL mode switch off. The word

9DUAL9 should not be displayed on the

ATC display panel. This will allow the DRIVER BLEND mode switch to control both
driver and pass temp settings.
Set the driver temperature to 60°F (16°C). The passenger temperature should also
display 60°F (16°C).
Monitor the DRBIII

t for active ATC DTCs while performing the following test steps.

Press the RECIRC mode switch on, wait 30 seconds, and then press it off.
Press the A/C mode switch on, wait 30 seconds, and then press it off.
Press the REAR DEFOG mode switch on, wait 30 seconds, and then press it off.
Press the EBL mode switch on, wait 30 seconds, and then press it off.
Press the DUAL mode switch on.
Set the driver temperature to the max heat setting, wait 30 seconds, and then set it
to the max cool setting. Repeat this step for the passenger temperature.
Press the MODE switch, placing the mode door in each position for 30 seconds, and
then return it to the panel position.
Press the AUTO HI mode switch, wait 30 seconds, and then press the AUTO LO mode
switch. When the function is complete, reset the front blower speed to low.
Turn the Rear Booster Fan Rear Control switch to AUTO for 30 seconds, then slowly
turn it from AUTO to high speed and then back to AUTO.
With the DRBIII

t in ATC, Miscellaneous, reset the ATC.

Does the DRBIII

t display any active ATC DTCs or Cooldown Test fault messages?

All

Yes

→ Return to the Heating & A/C symptom list and choose the

symptom(s)
Perform BODY VERIFICATION TEST - VER 1.

→ DTC may not have been erased after a repair. If possible, verify

recent service. Otherwise, inspect related wiring for chafed,
pierced, pinched, & partially broken wires & connectors for
broken, bent, pushed out, & corroded terminals. Repair as neces-
sary.
Perform BODY VERIFICATION TEST - VER 1.

541

HEATING & A/C

AC PRESSURE SENSOR FAULT (STORED) - ATC —

Continued

Symptom:

BACKLIGHT DIMMING RX FAILURE (ACTIVE) - MTC

When Monitored and Set Condition:

BACKLIGHT DIMMING RX FAILURE (ACTIVE) - MTC

When Monitored:

With the ignition on.

Set Condition:

If the A/C Heater Control does not receive the dimming function message

from the Body Control Module (BCM) for more than 5 seconds, then the mode switch status
indicators on the A/C Heater Control will default to daytime brightness and the DTC will
set.

POSSIBLE CAUSES

NO COMMUNICATION WITH BODY CONTROL MODULE (BCM)

BODY CONTROL MODULE (BCM) DTC(S) PRESENT

DIMMING MESSAGE NOT SEEN AT RATE EXPECTED

A/C HEATER CONTROL

BODY CONTROL MODULE (BCM)

TEST

ACTION

APPLICABILITY

Turn the ignition on.
With the DRBIII

t, attempt to communicate with the Body Control Module (BCM).

Was the DRBIII

t able to communicate with the Body Control Module (BCM)?

All

Yes

→ Go To 2

→ Refer to the Communication category for the related symptom.

Perform BODY VERIFICATION TEST - VER 1.

Turn the ignition on.
With the DRBIII

t, read Body Control Module (BCM) DTCs.

Does DRBIII

t display any DTCs?

All

Yes

→ Refer to the appropriate category for the related symptom(s).

Perform BODY VERIFICATION TEST - VER 1.

→ Go To 3

542

HEATING & A/C

TEST

ACTION

APPLICABILITY

NOTE: Make sure that the Panel Dimmer switch is not in set in Funeral
Mode.
Turn the ignition on.
Turn the park lamps on.
Press the A/C Heater Control’s power switch on.
Press the A/C mode switch on.
Press the EBL mode switch on.
Press the Recirc mode switch on.
Rotate the Panel Dimmer switch in both directions while watching the mode switch
status indicators on the A/C Heater Control.
Do the mode switch status indicators dim & brighten respectively?

All

Yes

→ No problem found at this time.

Perform BODY VERIFICATION TEST - VER 1.

→ Go To 4

Turn the ignition on.
With the DRBIII

t in HVAC, select Monitor Display and then select PCI Bus

Messages. From the list, select VF DIM Msg Present.
Does the DRBIII display: VF DIM Msg present: Yes?

All

Yes

→ Replace the A/C Heater Control in accordance with the Service

Information.
Perform BODY VERIFICATION TEST - VER 1.

→ Replace and program the Body Control Module (BCM) in accor-

dance with the Service Information.
Perform BODY VERIFICATION TEST - VER 1.

543

HEATING & A/C

BACKLIGHT DIMMING RX FAILURE (ACTIVE) - MTC —

Continued

Symptom List:

BLEND CALIBRATION FAULT - MTC
MODE CALIBRATION FAULT - MTC
RECIRCULATION CALIBRATION FAULT - MTC
ZONE CALIBRATION FAULT - MTC

Test Note:

All symptoms listed above are diagnosed using the same tests.

The title for the tests will be BLEND CALIBRATION FAULT -
MTC.

When Monitored and Set Condition:

BLEND CALIBRATION FAULT - MTC

When Monitored:

When the HVAC Door Recalibration is executed.

Set Condition:

If the passenger blend door’s span is found outside the tolerance due to:

open door actuator electrical circuits; a bad door actuator; broken door linkage; a bound up
door; door actuator electrical circuits shorted to voltage; door actuator electrical circuits
shorted to ground. A short to voltage or ground on the door actuator electrical circuits will
also set door actuator overcurrent faults.

MODE CALIBRATION FAULT - MTC

When Monitored:

When the HVAC Door Recalibration is executed.

Set Condition:

If the mode door’s span is found outside the tolerance due to: open door

actuator electrical circuits; a bad door actuator; broken door linkage; a bound up door; door
actuator electrical circuits shorted to voltage; door actuator electrical circuits shorted to
ground. A short to voltage or ground on the door actuator electrical circuits will also set
door actuator overcurrent faults.

RECIRCULATION CALIBRATION FAULT - MTC

When Monitored:

When the HVAC Door Recalibration is executed.

Set Condition:

If the recirculation door’s span is found outside the tolerance due to: open

door actuator electrical circuits; a bad door actuator; broken door linkage; a bound up door;
door actuator electrical circuits shorted to voltage; door actuator electrical circuits shorted
to ground. A short to voltage or ground on the door actuator electrical circuits will also set
door actuator overcurrent faults.

ZONE CALIBRATION FAULT - MTC

When Monitored:

When the HVAC Door Recalibration is executed.

Set Condition:

If the driver blend door’s span is found outside the tolerance due to: open

544

HEATING & A/C

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