Jeep Cherokee (XJ): On-board diagnostics (OBD). Accessory drive belt diagnosis. Preliminary checks
COOLING SYSTEM RELATED DIAGNOSTICS The Powertrain Control Module (PCM) has been
programmed to monitor the certain following cooling
system components: If the problem is sensed in a monitored circuit
often enough to indicate an actual problem, a DTC is
stored. The DTC will be stored in the PCM memory
for eventual display to the service technician. (Refer
to Group 25, Emission Control Systems for proper
procedures) ACCESSING DIAGNOSTIC TROUBLE CODES To read DTC's and to obtain cooling system data,
refer to Group 25, Emission Control Systems for
proper procedures. DRB scan tool For operation of the DRB scan tool, refer to the
appropriate Powertrain Diagnostic Procedures service
manual. VISUAL DIAGNOSIS When diagnosing serpentine accessory drive belts,
small cracks that run across the ribbed surface of the
belt from rib to rib (Fig. 16), are considered normal.
These are not a reason to replace the belt. However,
cracks running along a rib (not across) are not normal.
Any belt with cracks running along a rib must
be replaced (Fig. 16). Also replace the belt if it has
excessive wear, frayed cords or severe glazing.
Refer to the Accessory Drive Belt Diagnosis charts
for further belt diagnosis.
1 - NORMAL CRACKS BELT OK NOISE DIAGNOSIS Noises generated by the accessory drive belt are
most noticeable at idle. Before replacing a belt to
resolve a noise condition, inspect all of the accessory
drive pulleys for alignment, glazing, or excessive end
play. ACCESSORY DRIVE BELT DIAGNOSIS CHART CONDITION POSSIBLE CAUSES CORRECTION ENGINE COOLING SYSTEM OVERHEATING Establish what driving conditions caused the complaint.
Abnormal loads on the cooling system such as
the following may be the cause: PROLONGED IDLE, VERY HIGH AMBIENT TEMPERATURE,
SLIGHT TAIL WIND AT IDLE, SLOW TRAFFIC, TRAFFIC
JAMS, HIGH SPEED OR STEEP GRADES. Driving techniques that avoid overheating are: TRAILER TOWING: Consult Trailer Towing section of owners manual.
Do not exceed limits. AIR CONDITIONING; ADD-ON OR AFTER MARKET: A maximum cooling package should have been
ordered with vehicle if add-on or after market A/C is
installed. If not, maximum cooling system components
should be installed for model involved per
manufacturer's specifications. RECENT SERVICE OR ACCIDENT REPAIR: Determine if any recent service has been performed
on vehicle that may effect cooling system.
This may be: NOTE: If investigation reveals none of the previous
items as a cause for an engine overheating complaint,
refer to following Cooling System Diagnosis
charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information. COOLING SYSTEM DIAGNOSIS CHART CONDITION POSSIBLE CAUSES CORRECTIONOn-board diagnostics (OBD)
Accessory drive belt diagnosis
Fig. 16 Belt Wear Patterns
2 - NOT NORMAL CRACKS REPLACE BELT
RIB CHUNKING (One or more ribs
has separated from belt body)
RIB OR BELT WEAR
BELT SLIPS
LONGITUDAL BELT CRACKING
9GROOVE JUMPING"
(Belt does not maintain correct
position on pulley)
BELT BROKEN
(Note: Identify and correct problem
before new belt is installed)
NOISE (Objectionable squeal,
squeak, or rumble is heard or felt
while drive belt is in operation)
TENSION SHEETING FABRIC
FAILURE
(Woven fabric on outside,
circumference of belt has cracked or
separated from body of belt)
CORD EDGE FAILURE
(Tensile member exposed at edges
of belt or separated from belt body)
Preliminary checks
TEMPERATURE GAUGE READS
LOW
TEMPERATURE GAUGE READS
HIGH OR THE COOLANT
WARNING LAMP ILLUMINATES.
COOLANT MAY OR MAY NOT BE
LOST OR LEAKING FROM THE
COOLING SYSTEM
TEMPERATURE GAUGE READING
IS INCONSISTENT (FLUCTUATES,
CYCLES OR IS ERRATIC)
PRESSURE CAP IS BLOWING
OFF STEAM AND/OR COOLANT
TO COOLANT TANK.
TEMPERATURE GAUGE READING
MAY BE ABOVE NORMAL BUT
NOT HIGH. COOLANT LEVEL MAY
BE HIGH IN COOLANT RESERVE/
OVERFLOW TANK
COOLANT LOSS TO THE
GROUND WITHOUT PRESSURE
CAP BLOWOFF. GAUGE READING
HIGH OR HOT
DETONATION OR PRE-IGNITION
(NOT CAUSED BY IGNITION
SYSTEM). GAUGE MAY OR MAY
NOT BE READING HIGH
HOSE OR HOSES COLLAPSE
WHILE ENGINE IS RUNNING
ELECTRIC RADIATOR FAN RUNS
ALL OF THE TIME (2.5L/4.0L
MODELS EQUIPPED WITH A/C
AND 4.0L MODELS EQUIPPED
WITH MAX COOLING)
ELECTRIC RADIATOR FAN WILL
NOT RUN AT ALL. GAUGE
READING HIGH OR HOT
(2.5L/4.0L MODELS EQUIPPED
WITH A/C AND 4.0L MODELS
EQUIPPED WITH MAX COOLING)
NOISY VISCOUS FAN/DRIVE
INADEQUATE HEATER
PERFORMANCE. THERMOSTAT
FAILED IN OPEN POSITIO
STEAM IS COMING FROM THE
FRONT OF VEHICLE NEAR THE
GRILL AREA WHEN WEATHER IS
WET, ENGINE IS WARMED UP
AND RUNNING, AND VEHICLE IS
STATIONARY. TEMPERATURE
GAUGE IS IN NORMAL RANGE
COOLANT COLOR
COOLANT LEVEL CHANGES IN
COOLANT RESERVE/OVERFLOW
TANK. TEMPERATURE GAUGE IS
IN NORMAL RANGE
Radiator coolant flow check. Cooling system-testing for leaks. Viscous fan drive
Other materials:
Diagnosis and testing
Charging system
The following procedures may be used to diagnose
the charging system if:
the generator lamp (if equipped) is illuminated
with the engine running
the voltmeter (if equipped) does not register
properly
an undercharged or overcharged battery condition
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