Dodge Ram Truck 1500-2500-3500. Manual — part 2019
MODE 2 CALIBRATION FAULT
24 - 76
HVAC - ELECTRICAL DIAGNOSTICS
DR/DH
MODE 2 CALIBRATION FAULT (CONTINUED)
For the Manual Temperature Control circuit diagrams (Refer to 24 - HEATING & AIR CONDITIONING - SCHEMAT-
ICS AND DIAGRAMS).
For a complete wiring diagram Refer to Section 8W.
Theory of Operation
NOTE: Diagnose and repair Actuator Circuit Test faults before diagnosing Overcurrent faults and Calibration
faults. Diagnose and repair Overcurrent faults before diagnosing Calibration faults.
The purpose of actuator calibration is to determine the total span of door travel between physical stops. To calibrate
the actuator, the A/C Heater Control first moves the door to its soft stop, and then counts the number of pulses it
takes to move the door to its other stop. An expected range of span is stored in the control’s memory. If the mea-
sured calibration value is not within the expected range, this fault will set.
For vehicles equipped with electric backlight (EBL), running the HVAC Door Recalibration will cause the EBL status
indicator to flash. If recalibration fails, the EBL status indicator will continue to flash until either the system passes
recalibration or the ignition key is cycled. When the EBL status indicator is flashing, it will not indicate EBL operating
status. However, the EBL mode switch will continue to function normally. When the EBL status indicator is flashing,
the A/C status indicator will not function. However, the A/C mode switch will continue to function normally.
For vehicles not equipped with electric backlight (EBL), no status indicator will flash when running the HVAC Door
Recalibration. If recalibration fails, the A/C status indicator will not function, however, the A/C mode switch will con-
tinue to function normally.
•
When Monitored:
When HVAC Door Recalibration is executed.
•
Set Condition:
If the span of mode door 2 is found outside the tolerance.
Possible Causes
(C29) MODE DOOR 2 DRIVER CIRCUIT SHORTED TO GROUND (WILL ALSO SET OVERCURRENT DTCs)
(C29) MODE DOOR 2 DRIVER CIRCUIT SHORTED TO VOLTAGE (WILL ALSO SET OVERCURRENT DTCs)
(C29) MODE DOOR 2 DRIVER CIRCUIT OPEN
(C34) COMMON DOOR DRIVER CIRCUIT OPEN
MODE DOOR ACTUATOR 2 OPEN
MODE DOOR ACTUATOR 2 BROKEN
MODE DOOR 2 BOUND UP
MODE DOOR 2 LINKAGE MISSING, BROKEN
A/C HEATER CONTROL
Diagnostic Test
1.
RUN THE ACTUATOR CIRCUIT TEST
Turn the ignition on.
With the DRBIII
T
in HVAC, select System Tests and then select Actuator Circuit Test. Allow the test to run to com-
pletion before proceeding.
Does the DRBIII
T
display any Actuator Circuit Test fault messages?
Yes
>> Diagnose and repair the fault(s). For Single-Zone HVAC systems, refer to *ACTUATOR CIRCUIT TEST
DIAGNOSTICS (SINGLE-ZONE) in this section. For Dual-Zone HVAC systems, refer to *ACTUATOR
CIRCUIT TEST DIAGNOSTICS (DUAL-ZONE) in this section.
No
>> Go To 2
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HVAC - ELECTRICAL DIAGNOSTICS
24 - 77
MODE 2 CALIBRATION FAULT (CONTINUED)
2.
CHECK FOR DTCS IN THE A/C HEATER CONTROL
NOTE: Diagnose and repair all Overcurrent DTCs before diagnosing Calibration faults.
With the DRBIII
T
, read HVAC DTCs.
Does the DRBIII
T
display any DTCs?
Yes
>> Diagnose and repair the DTC(s). Refer to the Table of Contents in this Section for a complete list of
HVAC related symptoms.
No
>> Go To 3
3.
CHECK THE RESISTANCE BETWEEN THE (C34) COMMON DOOR DRIVER CIRCUIT & THE (C29) MODE
DOOR 2 DRIVER CIRCUIT
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance between the (C34) Common Door Driver cir-
cuit and the (C29) Mode Door 2 Driver circuit in the A/C Heater Con-
trol C1 harness connector.
Is the resistance above 70.0 ohms?
Yes
>> Go To 4
No
>> Go To 6
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HVAC - ELECTRICAL DIAGNOSTICS
DR/DH
MODE 2 CALIBRATION FAULT (CONTINUED)
4.
CHECK (C29) MODE DOOR 2 DRIVER CIRCUIT FOR AN OPEN
Disconnect the Mode Door Actuator 2 harness connector.
Measure the resistance of the (C29) Mode Door 2 Driver circuit
between the A/C Heater Control C1 harness connector and the Mode
Door Actuator 2 harness connector.
Is the resistance below 5.0 ohms?
Yes
>> Go To 5
No
>> Repair the (C29) Mode Door 2 Driver circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8
-
ELECTRICAL/ELECTRONIC
CONTROL
MODULES/
FRONT
CONTROL
MODULE
-
DIAGNOSIS
AND
TESTING).
5.
CHECK (C34) COMMON DOOR DRIVER CIRCUIT FOR AN OPEN
Measure the resistance of the (C34) Common Door Driver circuit
between the A/C Heater Control C1 harness connector and the Mode
Door Actuator 2 harness connector.
Is the resistance below 5.0 ohms?
Yes
>> Replace the Mode Door Actuator 2 in accordance with the
Service Information.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8
-
ELECTRICAL/ELECTRONIC
CONTROL
MODULES/
FRONT CONTROL MODULE - DIAGNOSIS AND TEST-
ING).
No
>> Repair the (C34) Common Door Driver circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. (Refer to 8
-
ELECTRICAL/ELECTRONIC
CONTROL
MODULES/
FRONT
CONTROL
MODULE
-
DIAGNOSIS
AND
TESTING).
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HVAC - ELECTRICAL DIAGNOSTICS
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