Symptom:
REAR IR SENSOR NOT CALIBRATED (ACTIVE)
When Monitored and Set Condition:
REAR IR SENSOR NOT CALIBRATED (ACTIVE)
When Monitored: With the ignition on and the IOD fuse installed.
Set Condition: This DTC is set if the ATC cannot read the IR sensor values or the IR
sensor values are not within a defined range of the HVAC air door motor counts.
POSSIBLE CAUSES
BCM
IGNITION SWITCH (RUN) CIRCUIT OPEN
KDB CLOCK CIRCUIT SHORTED TO VOLTAGE
KDB DATA CIRCUIT SHORTED TO GROUND
KDB DATA CIRCUIT SHORTED TO VOLTAGE
KDB CLOCK CIRCUIT SHORTED TO GROUND
KDB DATA CIRCUIT OPEN
ATC - KDB DATA CIRCUIT FAULT
KDB CLOCK CIRCUIT OPEN
ATC - KDB CLOCK CIRCUIT FAULT
REAR AUTOMATIC TEMPERATURE CONTROL SWITCH
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Turn the ignition on.
Measure the voltage of the Ignition Switch (Run) circuit.
Is the voltage above 10.0 volts?All
Ye s®Go To 2
No®Go To 13
2 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Turn the ignition on.
Measure the voltage of the KDB Data circuit.
Is the voltage above 10.0 volts?All
Ye s®Go To 3
No®Go To 10
276
AUTOMATIC TEMPERATURE CONTROL
TEST ACTION APPLICABILITY
3 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Turn the ignition on.
Measure the voltage of the KDB Data circuit.
Is the voltage above 1.0 volt?All
Ye s®Repair the KDB Data circuit for a short to voltage.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 4
4 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Use Scope input cable CH7058, Cable to Probe adapter CH7062, and the red and
black test probes.
Connect the scope input cable to the channel one connector on the DRB. Attach the
red and black leads and the cable to probe adapter to the scope input cable.
Select Lab Scope.
Select Live.
Select 12 volt square wave.
Press F2 for Scope.
Press F2 and use the arrows to set the voltage range to 20 volts, the Offset to 4.0, and
the Probe to x10. Press F2 again and set the divisions to 40ms/Div, then press F2
again when complete.
Connect the Black lead to the chassis ground. Connect the Red lead to the KDB Clock
circuit in the Rear Automatic Temperature Control Switch harness connector.
Turn the ignition on.
Observe the voltage display on the DRB Lab Scope.
NOTE: The lab scope pattern should look similar to the example given in the
support material and cycle from approximately 0 volts to 8.0 volts.
Did the lab scope pattern and voltage react as noted above?All
Ye s®Go To 5
No®Go To 6
5 If there are no possible causes remaining, view repair. All
Repair
Replace the Rear Automatic Temperature Control Switch.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
6 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Turn the ignition on.
Measure the voltage of the KDB Clock circuit.
Is the voltage above 1.0 volt?All
Ye s®Repair the KDB Clock circuit for a short to voltage.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 7
277
AUTOMATIC TEMPERATURE CONTROL
REAR IR SENSOR NOT CALIBRATED (ACTIVE) ÐContinued
TEST ACTION APPLICABILITY
7 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance between ground and the KDB Clock circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 8
No®Repair the KDB Clock circuit for a short to ground.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
8 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance of the KDB Clock circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 9
No®Repair the KDB Clock circuit for an open.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
9 If there are no possible causes remaining, view repair. All
Repair
Replace the ATC.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
10 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance between ground and the KDB Data circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 11
No®Repair the KDB Data circuit for a short to ground.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
11 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance of the KDB Data circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 12
No®Repair the KDB Data circuit for an open.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
278
AUTOMATIC TEMPERATURE CONTROL
REAR IR SENSOR NOT CALIBRATED (ACTIVE) ÐContinued
Symptom:
REAR KEYBOARD FAULT (ACTIVE)
POSSIBLE CAUSES
BCM
IGNITION SWITCH (RUN) CIRCUIT OPEN
KDB CLOCK CIRCUIT SHORTED TO VOLTAGE
KDB DATA CIRCUIT SHORTED TO GROUND
KDB DATA CIRCUIT SHORTED TO VOLTAGE
KDB CLOCK CIRCUIT SHORTED TO GROUND
KDB DATA CIRCUIT OPEN
ATC - KDB DATA CIRCUIT FAULT
KDB CLOCK CIRCUIT OPEN
ATC - KDB CLOCK CIRCUIT FAULT
REAR ATC SWITCH GROUND CIRCUIT OPEN
REAR AUTOMATIC TEMPERATURE CONTROL SWITCH
TEST ACTION APPLICABILITY
1 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Measure the resistance of the Rear ATC Switch Ground circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 2
No®Repair the Rear ATC Switch Ground circuit for an open.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
2 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Turn the ignition on.
Measure the voltage of the Ignition Switch (Run) circuit.
Is the voltage above 10.0 volts?All
Ye s®Go To 3
No®Go To 14
3 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Turn the ignition on.
Measure the voltage of the KDB Data circuit.
Is the voltage above 10.0 volts?All
Ye s®Go To 4
No®Go To 11
280
AUTOMATIC TEMPERATURE CONTROL
TEST ACTION APPLICABILITY
4 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Turn the ignition on.
Measure the voltage of the KDB Data circuit.
Is the voltage above 1.0 volt?All
Ye s®Repair the KDB Data circuit for a short to voltage.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 5
5 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Use Scope input cable CH7058, Cable to Probe adapter CH7062, and the red and
black test probes.
Connect the scope input cable to the channel one connector on the DRB. Attach the
red and black leads and the cable to probe adapter to the scope input cable.
Select Lab Scope.
Select Live.
Select 12 volt square wave.
Press F2 for Scope.
Press F2 and use the arrows to set the voltage range to 20 volts, the Offset to 4.0, and
the Probe to x10. Press F2 again and set the divisions to 40ms/Div, then press F2
again when complete.
Connect the Black lead to the chassis ground. Connect the Red lead to the KDB Clock
circuit in the Rear Automatic Temperature Control Switch harness connector.
Turn the ignition on.
Observe the voltage display on the DRB Lab Scope.
NOTE: The lab scope pattern should look similar to the example given in the
support material and cycle from approximately 0 volts to 8.0 volts.
Did the lab scope pattern and voltage react as noted above?All
Ye s®Go To 6
No®Go To 7
6 If there are no possible causes remaining, view repair. All
Repair
Replace the Rear Automatic Temperature Control Switch.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
7 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Turn the ignition on.
Measure the voltage of the KDB Clock circuit.
Is the voltage above 1.0 volt?All
Ye s®Repair the KDB Clock circuit for a short to voltage.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
No®Go To 8
281
AUTOMATIC TEMPERATURE CONTROL
REAR KEYBOARD FAULT (ACTIVE) ÐContinued
TEST ACTION APPLICABILITY
8 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance between ground and the KDB Clock circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 9
No®Repair the KDB Clock circuit for a short to ground.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
9 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance of the KDB Clock circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 10
No®Repair the KDB Clock circuit for an open.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
10 If there are no possible causes remaining, view repair. All
Repair
Replace the ATC.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
11 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance between ground and the KDB Data circuit.
Is the resistance above 100k ohms?All
Ye s®Go To 12
No®Repair the KDB Data circuit for a short to ground.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
12 Turn the ignition off.
Disconnect the Rear Automatic Temperature Control Switch harness connector.
Disconnect the ATC C2 harness connector.
Measure the resistance of the KDB Data circuit.
Is the resistance below 5.0 ohms?All
Ye s®Go To 13
No®Repair the KDB Data circuit for an open.
With the DRBIIIt, reset the ATC after repair/replacement is
complete.
Perform BODY VERIFICATION TEST - VER 1.
282
AUTOMATIC TEMPERATURE CONTROL
REAR KEYBOARD FAULT (ACTIVE) ÐContinued
lock the front wheels first. Any torque transfer from
the rear axle to the front axle disturbs the ABS/brak-
ing system and causes potential instabilities on a
slippery surface. The BOC de-couples the rear driv-
eline as soon the rear wheels begin to spin faster
than the front wheels (front wheels locked) in order
to provide increased braking stability. Furthermore
the BOC also reduces the likelihood of throttle off
over-steer during cornering. In a throttle off maneu-
ver, the BOC once again de-couples the rear driveline
forcing all the engine brake torque to the front
wheels. This eliminates the chance of lateral slip on
the rear axle and increases it on the front. The vehi-
cle will therefore tend to understeer, a situation
which is considered easier to manage in most circum-
stances. During this maneuver, and during the ABS
braking event, the BOC does not transmit torque
through to the rear wheels. The rear driveline mod-
ule, with the BOC, will perform the same as a front
wheel drive vehicle during these events. The gear
ratio offset between the front and rear differentials
force the BOC into the overrunning mode most of the
time. This allows BOC to significantly reduce the
rolling resistance of the vehicle, which improves fuel
consumption, allows the downsizing of the driveline
components, and prevents the PTU and propshaft
joints from overheating.
OPERATION
In order to achieve all-wheel drive operation in
reverse, the overrunning clutch locking functional
direction must be reversible. The bi-directional over-
running clutch (BOC) changes the operational mode
direction depending on the propeller shaft direction.
The propeller shaft rotates in the clockwise (when
viewed from the front) direction when the vehicle is
moving forward, which indexes the BOC to the for-
ward overrunning position. When the vehicle is in
reverse, the propeller shaft will rotate counter-clock-
wise and index the BOC to the reverse overrunning
position.
The BOC acts as a mechanical stator. It is active
(transmitting torque), or it is not active and in over-
running mode (not transmitting torque). This ªall or
nothingº approach to torque transfer would cause a
sudden application of all available power to the rear
wheels, which is not desirable. Therefore it is run in
series with a viscous coupler to smooth, dampen, and
limit the transmission of torque to the rear axle and
to prevent a step style torque input to the rear axle.
STEADY STATE, LOW TO MODERATE SPEED, NO
FRONT WHEEL SLIP, FORWARD DIRECTION
During normal driving conditions, (no wheel slip),
the inner shaft (front axle) and outer race (viscous
coupler) are running at different speeds due to the
different gear ratios between the front and rear dif-
ferentials. In this condition, the outer race is always
spinning faster (overdriving between 5-32 rpm) than
the inner shaft. When the BOC (Fig. 29) is running
under these conditions, at low vehicle speeds the
drag shoes and the cage keep the rollers up on the
left side (forward side) of the inner shaft flats. This is
what is known as ªoverrunning mode.º Notice that
when the clutch is in overrunning mode, the rollers
are spinning clockwise and with the outer race, thus
no torque is being transferred.
NOTE: Low speed, forward and reverse operation is
identical, just in opposite directions. (Fig. 29)
shows forward direction in reverse the rollers are
on the other side of the flats due to a reversal of
the cage force.
TRANSIENT CONDITION (BOC LOCKED), FRONT
WHEEL SLIP, FORWARD DIRECTION
When the front wheels lose traction and begin to
slip, the propeller shaft and rear axle pinion speed
difference decreases to zero. At this point the input
shaft (cam) becomes the driving member of the BOC
(Fig. 30), compressing the rollers against the outer
race. This locks the input shaft with the outer race
and transmits torque to the housing of the viscous
coupler, that in turn transmits torque to the rear
axle pinion. It should also be noted that when the
device is locked, the inner shaft and the outer race
are rotating at the same speed. The rollers are
pinched at this point and will stay locked until a
torque reversal (no front wheel slip) occurs. When
locked, the viscous coupler slips during the torque
transfer and the amount of torque transferred is
dependent on the coupling characteristic and the
amount of front wheel slip.
3 - 38 REAR DRIVELINE MODULERS
BI-DIRECTIONAL OVERRUNNING CLUTCH (Continued)
DIAGNOSIS AND TESTING - ENGINE COOLANT
THERMOSTAT
The thermostat is operated by a wax filled cham-
ber (pellet) which is sealed. When heated coolant
reaches a predetermined temperature the wax pellet
expands enough to overcome the closing spring and
water pump pressure, which forces the valve to open.
Coolant leakage into the pellet will cause a thermo-
stat to fail open. Do not attempt to free up a thermo-
stat with a screwdriver.
Thermostat diagnostics is included in powertrain
control module's (PCM) programing for on-board
diagnosis. The malfunction indicator light (MIL) will
illuminate and a diagnostic trouble code (DTC) will
be set when an ªopen too soonº condition occurs. Do
not change a thermostat for lack of heater perfor-
mance or temperature gauge position, unless a DTC
is present. For other probable causes, (Refer to 7 -
COOLING/ENGINE - DIAGNOSIS AND TESTING) .
Thermostat failing shut is the normal long term
mode of failure, and normally, only on high mileage
vehicles. The temperature gauge will indicate this
(Refer to 7 - COOLING/ENGINE - DIAGNOSIS AND
TESTING) .
ENGINE COOLANT
THERMOSTAT - 2.4L
REMOVAL
(1) Drain cooling system below the thermostat
level. (Refer to 7 - COOLING - STANDARD PROCE-
DURE)
(2) Remove radiator upper hose from the coolant
outlet housing (Fig. 7).
(3) Remove coolant outlet housing bolts and hous-
ing (Fig. 8).
(4) Remove thermostat. Discard gasket and clean
both gasket sealing surfaces.
INSTALLATION
(1) Place a new gasket (dipped in clean water) on
the coolant outlet connector surface. Position thermo-
stat with air bleed at the 12 o'clock position in ther-
mostat housing (Fig. 8).
(2) Position the coolant outlet connector and gas-
ket over the thermostat, making sure thermostat is
seated in the thermostat housing.
(3) Position outlet connector to thermostat housing
and install bolts (Fig. 8). Tighten bolts to 28 N´m
(250 in. lbs.).
(4) Install the radiator upper hose to coolant outlet
housing (Fig. 7).
(5) Refill the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
Fig. 7 RADIATOR HOSES TO ENGINE - 2.4L
1 - UPPER HOSE
2 - LOWER HOSE
Fig. 8 Thermostat and Outlet Connector - 2.4L
Engine
1 - THERMOSTAT
2 - GASKET
3 - COOLANT OUTLET CONNECTOR
4 - BOLT
7 - 22 ENGINERS
ENGINE COOLANT THERMOSTAT (Continued)