Chrysler Le Baron, Dodge Dynasty, Plymouth Acclaim. Manual - part 205

DIAGNOSTIC TROUBLE CODE 12—IN-CAR
TEMPERATURE SENSOR/ASPIRATOR
FAILURE

(1) Disconnect 21-way connector at control. With

an ohmmeter, measure the resistance between pin
#20 and pin #7. Refer to Temperature Refer-
ence—Diagnostic Trouble Code 11 chart for electrical
values.

(2) Check for continuity between pin #20 and

chassis ground. If continuity is present, repair and
retest.

DIAGNOSTIC TROUBLE CODE 13—BLEND
DOOR FAILED TO DRIVE TO HEAT POSITION

(1) Check door and linkage for binding.
(2) Disconnect 21-way connector from control head

and the 5-way connector from the blend air door ac-
tuator. Check continuity between pin #6 of the 21-
way connector and pin #5 of the 5-way connector. If
continuity is shown, go to step 3. If continuity is not
shown, repair circuit for an open circuit and retest
system.

(3) Plug in the 5-way connector and check for re-

sistance between pins #4 and #6 of the 21-way con-
nector. A resistance of 20-50 ohms should be present.
If not, replace actuator. If correct, proceed to step 4.

(4) If steps 1 and 2 indicate no failures, replace the

ATC control head.

DIAGNOSTIC TROUBLE CODE 14—BLEND
DOOR FAILED TO DRIVE TO COLD POSITION

First check the 5-way connector to the blend

air door actuator for proper connection

(1) Check door and linkage for binding.
(2) Remove the 21-way connector from the control.

With ignition ON, check for ignition voltage between
pin #8 of the 21-way connector and chassis ground.
If voltage is present, repair circuit for short to igni-
tion voltage. If voltage is not present, proceed to step
3.

(3) Turn ignition OFF. With the 21-way still re-

moved, disconnect the 5-way connector from the
blend air door actuator. Check for continuity between
pin #8 of the 21-way connector and pin #1 of the
5-way connector. If continuity is not present, repair
open circuit. If present, continue to step 4.

(4) Install the 5-way connector back into the blend

air door actuator and check for continuity between
the pins #7 and #8 of the 21-way connector. If con-
tinuity is present, replace the ATC control. If conti-
nuity is not present, replace the blend air door
actuator.

DIAGNOSTIC TROUBLE CODE 15—BLEND
DOOR FEEDBACK SHORTED TO GROUND

(1) Remove the 21-way connector from the control

and the 5-way connector from the blend air door ac-
tuator.

(2) Check for continuity between pin #8 of the 21-

way connector and chassis ground. If present, repair
circuit for short to ground. If not present, continue to
step 3.

(3) Plug in the 5-way connector and measure resis-

tance between pins #7 and #8 of the 21-way connec-
tor. If the resistance is less than 10 ohms, replace the
actuator. If not, replace the control head.

DIAGNOSTIC TROUBLE CODE 16—MODE
DOOR MOVED DURING BLEND DOOR TEST

(1) Remove the 21-way connector from the control

and the 5-way connector from the three actuators.

(2) Check for continuity between pin #4 of the 21-

way connector and pin #4 of each actuator. If conti-
nuity is not present for a particular actuator circuit,
repair that circuit and retest system. If continuity is
present for all circuits, continue to step 3.

(3) Plug in the 5-way connectors and check for re-

sistance between pins #4 and #6 of the 21-way con-
nector for the blend air actuator. Then check pins #4
and #5 of the 21-way for the mode actuator. The re-
sistance should be between 20-50 ohms. If either of
the actuators do not pass the resistance tests, replace
that particular actuator and retest the system. If
both pass the resistance test, replace the ATC con-
trol.

DIAGNOSTIC TROUBLE CODE 17—MODE
DOOR FAILED TO DRIVE TO DEFROST

(1) Disconnect 21-way connector from control head

and the 5-way connector from the blend air door ac-
tuator. Check continuity between pin #5 of the 21-
way connector and pin #5 of the 5-way connector. If
continuity is present, proceed to step 2. If continuity
is not present, repair open circuit and retest system.

(2) Plug in the 5-way connector and check for re-

sistance between pins #4 and #5 of the 21-way con-
nector. A resistance of 20-50 ohms should be present.
If not, replace actuator. If correct, proceed to step 3.

(3) If steps 1 and 2 do not indicate any failures, re-

place the ATC control head.

DIAGNOSTIC TROUBLE CODE 18—MODE
DOOR FAILED TO DRIVE TO PANEL

Check the 5-way connector to the mode door

actuator for proper installation.

(1) Check the door and linkage for binding.
(2) Remove the 21-way connector from the control.

With ignition ON, check for ignition voltage between
pin #16 of the 21-way connector and chassis ground.
If voltage is present, repair circuit for short to igni-
tion voltage. If voltage is not present, proceed to step
3.

(3) Turn ignition OFF. With the 21-way connector

still removed, disconnect the 5-way connector from
the mode door actuator. Check for continuity be-
tween pin #16 of the 21-way connector, and pin #1

HEATING AND AIR CONDITIONING

24 - 81

of the 5-way connector. If continuity is not present,
repair circuit for an open. If present, continue to step
4.

(4) Install 5-way connector back into the mode

door actuator. Then check for continuity between
pins #7 and #16 of the 21-way connector. If continu-
ity is present, replace the ATC control. If continuity
is not present, replace the mode door actuator.

DIAGNOSTIC TROUBLE CODE 19—MODE
DOOR FEEDBACK SHORTED TO GROUND

(1) Remove the 21-way connector from the control,

and the 5 way connector from the mode door actua-
tor.

(2) Check for continuity between pin #16 of the

21-way connector and chassis ground. If present, re-
pair circuit for short to ground. If not present, con-
tinue to step 3.

(3) Plug in the 5-way connector and measure resis-

tance between pins #7 and #16 of the 21-way con-
nector. If the resistance is less than 10 ohms, replace
the actuator. If not, replace the control head.

DIAGNOSTIC TROUBLE CODE 20—BLEND
DOOR MOVED DURING MODE DOOR TEST

(1) Remove the 21-way connector from the control

and the 5-way connector from the three actuators.

(2) Check for continuity between pin #4 of the 21-

(3) Plug in the 5-way connectors and check for re-

sistance between pins #4 and #6 of the 21-way con-
nector for the blend air actuator. Then check pins #4
and #5 of the 21-way connector for the mode actua-
tor. The resistance should be between 20-50 ohms. If
either of the actuators do not pass the resistance
tests, replace that particular actuator and retest the
system. If both pass the resistance test, replace the
ATC control.

DIAGNOSTIC TROUBLE CODE 21—ROM
CHECK SUM ERROR

During the Diagnostics test, the computer will ver-

ify it’s own internal program. If it finds any part to
be bad, a Diagnostic Trouble Code 21 will be set.
This Diagnostic Trouble Code is not serviceable. If a
Fail Code 21 occurs, the ATC Control Module must
be replaced.

DIAGNOSTIC TROUBLE CODE 22—COMPUTER
ERROR

If incorrect data is found in the ATC Control com-

puter module, a Diagnostic Trouble Code 22 will be
set. This Fail Code is not serviceable. If a Diagnostic
Trouble Code 22 occurs, the ATC Control Module
must be replaced.

DIAGNOSTIC TROUBLE CODE 23—BLEND
DOOR FEEDBACK FAILED

This Diagnostic Trouble Code is set during normal

ATC operation. The Diagnostic Trouble Code will be
set only after the ATC control has been operating for
15 minutes. The control will compensate for the feed-
back failure immediately upon power up, but the Di-
agnostic Trouble Code will not be set until the time
limit has been met.

Diagnostic Trouble Code 23 will be stored within

the ATC Control, and must be cleared after the fail-
ure has been repaired. To clear this Diagnostic Trou-
ble Code, refer to Erasing Diagnostic Trouble Codes
23 through 28 from ATC Control.

Follow service procedures for Diagnostic Trouble

Codes 14 and 15 when repairing.

DIAGNOSTIC TROUBLE CODE 24—MODE
DOOR FEEDBACK FAILED

This Diagnostic Trouble Code is set during normal

Diagnostic Trouble Code 24 will be stored within

the ATC Control, and must be cleared after the fail-
ure has been repaired. To clear this Diagnostic Trou-
ble Code, refer to Erasing Diagnostic Trouble Codes
23 through 28 From ATC Control.

Follow service procedures for Diagnostic Trouble

Codes 18 and 19 when repairing.

DIAGNOSTIC TROUBLE CODE 25—AMBIENT
TEMPERATURE SENSOR FAILURE

This Diagnostic Trouble Code is set during normal

Diagnostic Trouble Code 25 will be stored within

the ATC Control, and must be cleared after the fail-
ure has been repaired. To clear this Diagnostic Trou-
ble Code, refer to Erasing Diagnostic Trouble Codes
23 through 28 from ATC Control.

Follow service procedures for Diagnostic Trouble

Code 11 when repairing.

DIAGNOSTIC TROUBLE CODE 26—IN-CAR
TEMPERATURE SENSOR/ASPIRATOR FAILED

This Diagnostic Trouble Code is set during normal

ATC operation. The Diagnostic Trouble Code will be
set only after the ATC control has been operating for
15 minutes. The control will compensate for the feed-

24 - 82

HEATING AND AIR CONDITIONING

back failure immediately upon power up, but the Di-
agnostic Trouble Code will not be set until the time
limit has been met.

Diagnostic Trouble Code 26 will be stored within

the ATC Control, and must be cleared after the fail-
ure has been repaired. To clear this Diagnostic Trou-
ble Code, refer to Erasing Diagnostic Trouble Codes
23 through 28 from ATC Control.

Follow service procedures for Diagnostic Trouble

Code 12 when repairing.

DIAGNOSTIC TROUBLE CODE 27—SUN LOAD
SENSOR FAILED

This Diagnostic Trouble Code is set during normal

Diagnostic Trouble Code 27 will be stored within

the ATC Control, and must be cleared after the fail-
ure has been repaired. To clear this Diagnostic Trou-
ble Code, refer to Erasing Diagnostic Trouble Codes
23 through 28 from ATC Control.

Follow service procedures for Diagnostic Trouble

Code 12 when repairing.

DIAGNOSTIC TROUBLE CODE 28—WATER
TEMPERATURE SENSOR FAILED

This Diagnostic Trouble Code is set during normal

Diagnostic Trouble Code 28 will be stored within

the ATC Control and must be cleared after the fail-

ure has been repaired. To clear this Diagnostic Trou-
ble Code, refer to Erasing Diagnostic Trouble Codes
23 through 28 from ATC Control.

Follow service procedures for Diagnostic Trouble

Code 10 when repairing.

ERASING DIAGNOSTIC TROUBLE CODES

Diagnostic Trouble Codes 23 through 28 are stored

within the ATC in the computer memory. These
codes may be erased from the memory after the cor-
rect repairs have been made. Intermittent Diagnostic
Trouble Codes 23 through 28 will be stored until
they are erased.

(1) Run the DIAGNOSTIC TEST.
(2) Depress the PANEL button to access all Diag-

nostic Trouble Codes. When the Display begins flash-
ing alternating zeros, you can do three things:
• Do nothing, and in five seconds control will return
to normal ATC operation. All codes will remain
stored in the control.
• Depress any button within five seconds, other than
A/C, and stop the test immediately. Control will re-
turn to normal ATC operation.
• Depress the A/C button within five seconds, and
proceed to the erasing procedure. By depressing the
A/C button, you will not erase any Diagnostic Trou-
ble Codes. You will only access the next part of the
procedure. Proceed to step 3.

(3) After you depress the A/C button the display

will alternate E’s. This is for ERASE. You can now
do two things:
• Do nothing, and in five seconds, all Diagnostic
Trouble Codes from 23 through 28 will be erased
from the ATC control.
• Depress any button within five seconds, and Diag-
nostic Trouble Codes will not be erased.

Control will return to normal ATC operation.

HEATING AND AIR CONDITIONING

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