
When Monitored:
The ignition on. T-Case Switch in 4W/LO position.
Set Condition:
The TIPM detects that the Front Axle Lock Signal circuit is shorted low.
Possible Causes
(A880) FUSED B+ CIRCUIT OPEN
(G303) FRONT AXLE LOCK SIGNAL CIRCUIT OPEN
(G304) FRONT AXLE LOCK CONTROL CIRCUIT OPEN
FRONT AXLE DISCONNECT (FAD) MODULE
TOTALLY INTEGRATED POWER MODULE (TIPM)
Diagnostic Test
1.ACTIVE DTC
CAUTION: Before removing the TIPM harness connectors, clean the connector and locking cam area of dirt
and debris. Failure to do so can result in the connector being jammed or damage to the locking cams on
the harness connector or module. Do not force the assist arm when releasingor installing the harness con-
nector.
Ignition on, engine not running.
With the scan tool, read the TIPM DTCs.
Is the status Active for this DTC?
Ye s>>
Go To 2
No>>
Go To 6
2.(A880) FUSED B+ OPEN
Turn the ignition off to the lock position.
Disconnect the FAD harness connector.
Ignition on, engine not running.
With the scan tool, actuate the Front Axle Lock Signal in the TIPM.
Using a 12-volt test light connected to ground, check the (A880) Front
Axle Lock Signal circuit in the FAD harness connector.
Does the test light illuminate brightly?
Ye s>>
Go To 3
No>>
Repair the (A880) Fused B+ circuit for an open.
Perform the TRANSFER CASE VERIFICATION TEST-VER
1. (Refer to 21 - TRANSMISSION/TRANSAXLE/TRANSFER
CASE - STANDARD PROCEDURE)

3.CHECK FOR A SHORTED CONDENSER FAN MOTOR
Reconnect the TIPM C8 harness connector.
Ignition on, engine not running.
With the scan tool, actuate the Condenser Fan.
Using a 12-volt test light connected to ground, probe the (C123) Con-
denser Fan Control Output circuit at the Condenser Fan Motor harness
connector.
Does the test light illuminate brightly and flash on and off?
Ye s>>
With the scan tool, de-actuate the Condenser Fan. Then,
replace the Condenser Fan Motor in accordance with the
Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
No>>
With the scan tool, de-actuate the Condenser Fan. Then,
Go To 4
4.INSPECT RELATED WIRING
NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Turn the ignition off.
Using the schematics as a guide, inspect the related wiring harness and connectors.
Pay particular attention to all Power and Ground circuits.
Were any problems found?
Ye s>>
Repair as necessary.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
No>>
Replace the TIPM in accordance with the Service Information.
Perform the BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES - STANDARD PROCEDURE)

When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.
Set Condition:
If the Totally Integrated Power Module (TIPM) detects a shorted high condition in the (C123) Condenser Fan
Control circuit.
Possible Causes
(C123) CONDENSER FAN CONTROL OUTPUT CIRCUIT SHORTED TO BATTERY VOLTAGE
EXCESSIVE RESISTANCE IN THE (Z823) GROUND CIRCUIT
CONDENSER FAN MOTOR
TIPM
Diagnostic Test
1.VERIFY DTC IS ACTIVE
Turn the ignition on.
With the scan tool, erase TIPM DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, actuate the Condenser Fan.
With the scan tool, read TIPM DTCs.
Does this DTC reset?
Ye s>>
With the scan tool, de-actuate the Condenser Fan. Then, Go To 2
No>>
With the scan tool, de-actuate the Condenser Fan. Then, check for an intermittent condition by inspect-
ing the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the
related connectors for broken, bent, corroded, and contaminated terminals.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
2.CHECK (C123) CONDENSER FAN CONTROL OUTPUT CIRCUIT FOR A SHORT TO BATTERY VOLTA G E
Turn the ignition off
Disconnect the TIPM C8 harness connector.
Disconnect the Condenser Fan Motor harness connector.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (C123) Con-
denser Fan Control Output circuit at the Condenser Fan Motor harness
connector.
Does the test light illuminate?
Ye s>>
Repair the (C123) Condenser Fan Control Output circuit for
a short to battery voltage.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
No>>
Go To 3

3.CHECK (Z823) GROUND CIRCUIT FOR AN OPEN
Turn the ignition off.
Reconnect the TIPM C8 harness connector.
NOTE: The test light should illuminate brightly. Compare the
brightness to that of a direct connection to the battery.
Using a 12-volt test light connected to 12 volts, probe the (Z823)
Ground circuit at the Condenser Fan Motor harness connector.
Does the test light illuminate brightly?
Ye s>>
Go To 4
No>>
Repair the excessive resistance in the (Z823) Ground cir-
cuit.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
4.CHECK CONDENSER FAN MOTOR
Ignition on, engine not running.
With the scan tool, actuate the Condenser Fan.
Using a 12-volt test light connected to ground, probe the (C123) Con-
denser Fan Control Output circuit at the Condenser Fan Motor harness
connector.
Does the test light illuminate brightly and flash on and off?
Ye s>>
With the scan tool, de-actuate the Condenser Fan. Then,
replace the Condenser Fan Motor in accordance with the
Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
No>>
With the scan tool, de-actuate the Condenser Fan. Then,
Go To 5
5.INSPECT RELATED WIRING
NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the related wiring harness and connectors.
Pay particular attention to all Power and Ground circuits.
Were any problems found?
Ye s>>
Repair as necessary.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
No>>
Replace the TIPM in accordance with the Service Information.
Perform the BODY VERIFICATION TEST – VER 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

3.CHECK CONDENSER FAN MOTOR
Reconnect the TIPM C8 harness connector.
Ignition on, engine not running.
With the scan tool, actuate the Condenser Fan.
Using a 12-volt test light connected to ground, probe the (C123) Con-
denser Fan Control Output circuit at the Condenser Fan harness con-
nector.
Does the test light illuminate brightly and flash on and off?
Ye s>>
With the scan tool, de-actuate the Condenser Fan. Then,
replace the Condenser Fan Motor in accordance with the
Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
No>>
With the scan tool, de-actuate the Condenser Fan. Then,
Go To 4
4.INSPECT RELATED WIRING
NOTE: Before continuing, check the TIPM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors.
Pay particular attention to all Power and Ground circuits.
Were any problems found?
Ye s>>
Repair as necessary.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).
No>>
Replace the Totally Integrated Power Module in accordance with the Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).

5.CHECK (C123) CONDENSER FAN CONTROL OUTPUT FROM TIPM
Reconnect the TIPM C8 harness connector.
Ignition on, engine not running.
With a scan tool, actuate the Condenser Fan.
Using the 12-Volt test light connected to ground, probe the (C123) Con-
denser Fan Control Output circuit in the Condenser Fan Motor harness
connector.
Does the test light illuminate brightly?
Ye s>>
With a scan tool, de-actuate the Condenser Fan. Then,
replace the Condenser Fan Motor in accordance with the
Service Information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MODULES -
STANDARD PROCEDURE).
No>>
With a scan tool, de-actuate the Condenser Fan. Then,
replace the TIPM in accordance with the Service Informa-
tion.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES - STANDARD PROCEDURE).

Condition Possible Causes Correction
5. Engine overheating.5. Refer to Cooling for more information. Test the
cooling system and repair, if required.
The low side pressure is too
high, and the high side
pressure is too low.1. Accessory drive belt
slipping.1. Refer to Cooling for more information. Inspect
the accessory drive belt condition and tension.
Tighten or replace the accessory drive belt, if
required.
2. Fixed orifice tube not
installed.2. See A/C Orifice Tube in this group. Replace the
liquid line, if required.
3. Faulty A/C compressor.3. See A/C Compressor in this group. Replace the
compressor, if required.
The low side pressure is too
low, and the high side
pressure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid, Suction, and Discharge Line in this
group. Inspect the refrigerant lines for kinks, tight
bends or improper routing. Correct the routing or
replace the refrigerant line, if required.
2. Restricted refrigerant flow
through the fixed orifice
tube.2. See A/C Orifice Tube in this group. Replace the
liquid line, if required.
3. Restricted refrigerant flow
through the condenser.3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
HEATER PERFORMANCE
Before performing the following tests, refer to Group 7 - Cooling for the procedures to check the engine coolant
level and flow, engine coolant reserve/recovery system operation, accessory drive belt condition and tension, radi-
ator air flow and the fan drive operation. Perform the HVAC System Test (refer to 24 - HVAC Electrical Diagnostics).
If any diagnostic trouble codes (DTCs) are found in the A/C-heater control, powertrain control module (PCM) or
engine control module (ECM) (depending on engine application), gateway module or totally integrated power module
(TIPM), repair as necessary.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system through two heater hoses. With the engine idling at normal oper-
ating temperature, set the temperature control to maximum heat position,the mode control to the floor position, and
the blower motor control to the highest speed position. Using a test thermometer, check the temperature of the air
being discharged from the floor outlets. Compare the test thermometer reading to the Heater Temperature Refer-
ence chart.
HEATER TEMPERATURE REFERENCE
Ambient Air Temperature16° C
(60° F)21° C
(70° F)26° C
(80° F)32° C
(90° F)
Minimum Air Temperature at
Floor Outlet62° C
(144° F)64° C
(147° F)65° C
(150° F)67° C
(153° F)
If the heater outlet air temperature is below the minimum specification, refer to Group 7 - Cooling. Both of the heater
hoses should be hot to the touch. The coolant return heater hose should be slightly cooler than the coolant supply
heater hose. If the return hose is much cooler than the supply hose, locate and repair the engine coolant flow
obstruction in the cooling system. RefertoGroup7-Coolingformoreinformation.
OBSTRUCTED COOLANT FLOW
Possible locations or causes of obstructed coolant flow are as follows:
Faulty water pump.
Faulty thermostat.
Pinched or kinked heater hoses.

TUBE-A/C ORIFICE
DESCRIPTION
The fixed A/C orifice tube is installed in the A/C liquid
line and provides a restriction in the liquid refrigerant
line between the A/C condenser and the A/C evapora-
tor. This restriction established the pressure differential
between the high and low-pressure sides of the A/C
system.
The A/C orifice tube includes a diffuser screen (1),
O-ring seals (2) to seal it to the inner wall of the A/C
liquid line, an inlet filter screen (3) and the fixed orifice
(4).
OPERATION
The fixed A/C orifice tube is used to meter the flow of liquid refrigerant into the A/C evaporator. The high-pressure
liquid refrigerant from the A/C condenser expands into a low-pressure liquid as it passes through the metering orifice
and diffuser screen of the A/C orifice tube.
The A/C orifice tube is not serviceable and cannot be repaired and, if faulty or plugged, the A/C liquid line must be
replaced (Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING/LINE-A/C LIQUID - DESCRIPTION).
DIAGNOSIS AND TESTING
A/C ORIFICE TUBE
WARNING: The A/C liquid line between the A/C condenser and the A/C orifice tube can become hot enough
to burn the skin. Use extreme caution when performing the following test toprevent possible personal
injury.
NOTE: The A/C orifice tube can be checked for proper operation using the following procedure. However,
the A/C orifice tube is only serviced as a part of the A/C liquid line. If the results of this test indicate that the
A/C orifice tube is obstructed or missing, the A/C liquid line must be replaced.
1. Confirm that the refrigerant system is properly charged (Refer to 24 - HEATING & AIR CONDITIONING - DIAG-
NOSIS AND TESTING - A/C PERFORMANCE).
2. Start the engine. Turn on the A/Csystem and confirm that the compressor clutch is engaged.
3. Allow the A/C system to operate for five minutes.
4. Lightly and cautiously touch the A/C liquid line near the condenser outlet at the front of the engine compartment.
TheA/Cliquidlineshouldbehottothetouch.
5. Touch the A/C liquid line near the evaporator inlet at the rear of the engine compartment. The A/C liquid line
should be cold to the touch.
6. If there is a distinct temperature differential between the two ends of the A/C liquid line, the A/C orifice tube is in
good condition. If there is little or no detectable temperature differential between the two ends of the A/C liquid
line, the A/C orifice tube is obstructed or missing and the A/C liquid line must be replaced (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/LINE-A/C LIQUID - REMOVAL).