Page 4001 of 4284
Symptom:
P1486-EVAP LEAK MONITOR PINCHED HOSE FOUND
When Monitored and Set Condition:
P1486-EVAP LEAK MONITOR PINCHED HOSE FOUND
When Monitored: Immediately after a cold start, with battery/ambient temperature
between 4ÉC (40ÉF) and 32ÉC (90ÉF) and coolant temperature within -12ÉC (10ÉF) of
battery/ambient.
Set Condition: LDP Switch does not reach at least 3 closures with 10 seconds. LDP must
initial in normal conditions to mature failure.
POSSIBLE CAUSES
INTERMITTENT LDP MONITOR FAILURE
OBSTRUCTION IN EVAP SYSTEM BETWEEN EVAP CANISTER AND FUEL TANK
EVAP CANISTER OBSTRUCTED
OBSTRUCTION IN HOSE/TUBE BETWEEN EVAP CANISTER AND PURGE SOLENOID
LDP PRESSURE HOSE OBSTRUCTED
LEAK DETECTION PUMP
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 6
207
DRIVEABILITY - GAS
Page 4002 of 4284

TEST ACTION APPLICABILITY
2 To continue testing you will need Miller Tools #6872A Evap System Pressure Pump
and #8382 Gas Cap Tester Adapter.
WARNING: The test equipment is designed to be used to pressurize the
vehicles Evaporative System only. Using the equipment in a manner for
which it was not designed could be harmful.
Warning: Keep lighted cigarettes, sparks, flames, and other ignition sources
away from the test area to prevent the ignition of explosive gases. Keep the
test area well ventilated.
Note: The fuel tank should have between 20% & 80% of full to properly test
the Evap system.
Attach the power source red clip of Miller Tool #6872A to Battery (+) and the ground
black clip to Battery (-).
Perform the Evaporative System Pressure Pump self test that is specified on the
tester cover.
Remove gas cap and install Miller Tool #8382 on vehicle. Install gas cap to Miller Tool
#8382. Attach the pressure supply hose from Miller Tool #6872A to the fitting on
#8382.
Disconnect the vacuum supply hose at the Leak Detection Pump. Connect and apply
a continuous vacuum supply (i.e. 209Hg) to the Leak Detection Pump. A vacuum
pump such as an A/C recovery unit works well.
Turn the ignition on.
With the DRBIIItin System Tests, select Leak Detect Pump Test. Read instructions
and then press Enter. Select: #3 - HOLD PSI.
On Miller Tool #6872A, set the Pressure/Hold switch to Open and set the Vent switch
to Closed. Turn the pump timer On and watch the gauge.
When the gauge pressure reaches 149H2O, turn the Pressure/Hold Valve to Closed.
Turn the pump timer off.
Disconnect the hose at the EVAP Canister that goes to the Fuel Tank.
Did the pressure drop when the hose was disconnected?All
Ye s®Go To 3
No®Repair obstruction in the EVAP system between the EVAP
Canister and the fuel tank.
Perform POWERTRAIN VERIFICATION TEST VER - 6.
3Note: All previously disconnected hose(s) reconnected.
Re-pressurize the EVAP System. On Miller Tool #6872A, set the Pressure/Hold
switch to Open and set the Vent switch to Closed. Turn the pump timer On and watch
the gauge.
When the gauge pressure reaches 149H2O, turn the Pressure/Hold Valve to Closed.
Turn the pump timer off.
Disconnect the LDP Pressure hose at the EVAP Canister. The LDP Pressure hose is
the hose that connects the Evap Canister to the Leak Detection Pump.
Did the pressure drop when the hose was disconnected?All
Ye s®Go To 4
No®Replace the EVAP Canister.
Perform POWERTRAIN VERIFICATION TEST VER - 6.
208
DRIVEABILITY - GAS
P1486-EVAP LEAK MONITOR PINCHED HOSE FOUND ÐContinued
Page 4003 of 4284

TEST ACTION APPLICABILITY
4Note: All previously disconnected hose(s) reconnected.
Re-pressurize the EVAP System. On Miller Tool #6872A, set the Pressure/Hold
switch to Open and set the Vent switch to Closed. Turn the pump timer On and watch
the gauge.
When the gauge pressure reaches 149H2O, turn the Pressure/Hold Valve to Closed.
Turn the pump timer off.
Disconnect the EVAP hoses at the Purge Solenoid.
Did the pressure drop when the hose was disconnected?All
Ye s®Go To 5
No®Repair or replace hose/tube as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 6.
5 Disconnect and remove the LDP pressure hose. The LDP pressure hose is the hose
that connects the EVAP Canister to the Leak Detection Pump.
Inspect the LDP pressure hose for any obstructions or physical damage.
Is the LDP pressure hose free from defects?All
Ye s®Replace the Leak Detection Pump.
Perform POWERTRAIN VERIFICATION TEST VER - 6.
No®Repair/replace hose as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 6.
6 At this time, the conditions required to set the DTC are not present.
Note: Use the Freeze Frame Data to help you duplicate the conditions that
set the DTC. Pay particular attention to the DTC set conditions, such as,
VSS, MAP, ECT, and Load.
Note: A thorough visual inspection of the Evap system hoses, tubes, and
connections may save time in your diagnosis. Look for any physical damage
or signs of wetness at connections. The strong smell of fuel vapors may aid
diagnosis also.
Note: Refer to any Technical Service Bulletins (TSB's) that may apply.
With the DRBIIItin System Tests, perform the LDP Monitor Test. This will force the
PCM to run the LDP Monitor. If the monitor fails, further diagnosis is required to
find faulty component. If the monitor passes, the condition is not present at this time.
Were any problems found?All
Ye s®Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 6.
No®Test Complete.
209
DRIVEABILITY - GAS
P1486-EVAP LEAK MONITOR PINCHED HOSE FOUND ÐContinued
Page 4004 of 4284

Symptom:
P1491-RAD FAN CONTROL RELAY CIRCUIT
When Monitored and Set Condition:
P1491-RAD FAN CONTROL RELAY CIRCUIT
When Monitored: With the ignition on. Battery voltage greater than 10 volts.
Set Condition: An open or shorted circuit is detected in the radiator fan relay control
circuit.
POSSIBLE CAUSES
RADIATOR FAN RELAY INTERMITTENT OPERATION
INTERMITTENT CONDITION
GROUND CIRCUIT
FUSED B+ OUTPUT CIRCUIT
POWERTRAIN CONTROL MODULE
RADIATOR FAN RELAY CONTROL CIRCUIT SHORT TO GROUND
RADIATOR FAN RELAY CONTROL CIRCUIT OPEN (IPM)
RADIATOR FAN RELAY CONTROL CIRCUIT OPEN (PCM)
RADIATOR FAN RELAY CONTROL CIRCUIT SHORTED TO GROUND (IPM)
RADIATOR FAN RELAY CONTROL CIRCUIT SHORT TO GROUND (PCM)
INTELLIGENT POWER MODULE (OPEN)
INTELLIGENT POWER MODULE (SHORTED)
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, actuate the Radiator Fan Relay.
Are both Radiator Fan operating?All
Ye s®Go To 2
No®Go To 4
2 Turn the ignition on.
With the DRBIIIt, actuate the Radiator Fan Relay.
Wiggle the wiring harness from the Radiator Fan Relay to the PCM while the relay
is actuating.
Did the Radiator Fan Relay stop when wiggling the wiring harness?All
Ye s®Repair as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 3
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Page 4005 of 4284

TEST ACTION APPLICABILITY
3WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE
PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.
NOTE: The conditions that set the DTC are not present at this time. The
following list may help in identifying the intermittent condition.
With the engine running at normal operating temperature, monitor the DRB
parameters related to the DTC while wiggling the wiring harness. Look for param-
eter values to change and/or a DTC to set.
Review the DRB Freeze Frame information. If possible, try to duplicate the
conditions under which the DTC was set.
Refer to any Technical Service Bulletins (TSB) that may apply.
Visually inspect the related wiring harness. Look for any chafed, pierced, pinched, or
partially broken wires.
Visually inspect the related wiring harness connectors. Look for broken, bent, pushed
out, or corroded terminals.
Were any of the above conditions present?All
Ye s®Repair as necessary
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Test Complete.
4 Turn the ignition off.
Disconnect the Radiator Fan Relay harness connector.
Using a 12-volt test light connected to 12-volts, probe the Ground circuit in the
Radiator Fan Relay harness connector.
Does the test light illuminate?All
Ye s®Go To 5
No®Repair the Ground circuit for an open.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
5NOTE: Inspect the Radiator Fan fuse located in the IPM.
Turn the ignition off.
Disconnect the Radiator Fan Relay harness connector.
Measure the voltage of the Fused B+ Output circuit in the Radiator Fan Relay
harness connector.
Is the voltage above 11.0 volts?All
Ye s®Go To 6
No®Repair the Fused B+ circuit. Check and replace any open fuses.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
6NOTE: Ensure the Radiator Fan Relay harness connector is connected.
Turn the ignition off.
Disconnect the PCM harness connector.
Turn the ignition on.
Using a jumper wire, momentarily jumper the Radiator Fan Relay Control circuit to
ground.
Did the Radiator Fans operate?All
Ye s®Replace and program the Powertrain Control Module in accor-
dance with the Service Information.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 7
211
DRIVEABILITY - GAS
P1491-RAD FAN CONTROL RELAY CIRCUIT ÐContinued
Page 4006 of 4284

TEST ACTION APPLICABILITY
7 Turn the ignition off.
Disconnect the Radiator Fan Relay harness connector.
Disconnect the PCM harness connector.
Measure the resistance of the Radiator Fan Relay Control circuit between the
Radiator Fan Relay harness connector and the PCM harness connector.
Is the resistance below 5.0 ohms?All
Ye s®Go To 8
No®Go To 11
8 Turn the ignition off.
Disconnect the Radiator Fan Relay harness connector.
Disconnect the PCM harness connector.
Measure the resistance of the Radiator Fan Relay Control circuit in the Radiator Fan
Relay harness connector to ground.
Is the resistance below 5.0 ohms?All
Ye s®Go To 9
No®Replace Radiator Fan Relay.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
9 Turn the ignition off.
Disconnect the Radiator Fan Relay harness connector.
Disconnect the IPM C2 harness connector.
Measure the resistance of the Radiator Fan Relay Control circuit in the Radiator Fan
Relay harness connector to ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Radiator Fan Relay Control circuit for a short to
ground between the Radiator Fan Relay harness connector and
the IPM harness connector.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Go To 10
10 Turn the ignition off.
Disconnect the PCM harness connector.
Disconnect the IPM C3 harness connector.
Measure the resistance of the Radiator Fan Relay Control circuit in the PCM harness
connector to ground.
Is the resistance below 5.0 ohms?All
Ye s®Repair the Radiator Fan Relay Control circuit for a short to
ground between PCM harness connector and the IPM harness
connector.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Replace the IPM Fuse & Relay Center.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
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DRIVEABILITY - GAS
P1491-RAD FAN CONTROL RELAY CIRCUIT ÐContinued
Page 4007 of 4284

TEST ACTION APPLICABILITY
11 Turn the ignition off.
Disconnect the Radiator Fan Relay harness connector.
Disconnect the IPM C2 harness connector.
Measure the resistance of the Radiator Fan Relay Control circuit between the IPM
harness connector and the Radiator Fan Relay harness connector.
Is the resistance below 5.0 ohms.All
Ye s®Go To 12
No®Repair the Radiator Fan Relay Control circuit for an open
between the Radiator Fan Relay harness connector and the IPM
harness connector.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
12 Turn the ignition off.
Disconnect the PCM harness connector.
Disconnect the IPM C3 harness connector.
Measure the resistance of the Radiator Fan Relay Control circuit between the IPM
harness connector and the PCM harness connector.
Is the resistance below 5.0 ohms.All
Ye s®Replace the IPM Fuse & Relay Center.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
No®Repair the Radiator Fan Relay Control circuit for an open
between PCM harness connector and the IPM harness connector.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
213
DRIVEABILITY - GAS
P1491-RAD FAN CONTROL RELAY CIRCUIT ÐContinued
Page 4008 of 4284

Symptom:
P1494-LEAK DETECT PUMP SW OR MECHANICAL FAULT
When Monitored and Set Condition:
P1494-LEAK DETECT PUMP SW OR MECHANICAL FAULT
When Monitored: Immediately after a cold start, with battery/ambient temperature
between 4ÉC (40ÉF) and 32ÉC (90ÉF) and coolant temperature within -12ÉC (10ÉF) of
battery/ambient.
Set Condition: The state of the switch does not change when the solenoid is energized.
POSSIBLE CAUSES
LDP VACUUM SUPPLY
WIRING HARNESS INTERMITTENT
LEAK DETECTION PUMP
LDP SWITCH SENSE CIRCUIT SHORTED TO GROUND
LDP SWITCH SENSE CIRCUIT OPEN
POWERTRAIN CONTROL MODULE
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRBIIIt, read DTC's.
Is the Good Trip displayed and equal to zero?All
Ye s®Go To 2
No®Go To 7
2 Turn the ignition off.
Disconnect the vacuum supply hose at the Leak Detection Pump.
Connect a vacuum gauge to the disconnected vacuum supply hose at the Leak
Detection Pump.
Start the engine and read the vacuum gauge.
Does the vacuum gauge read at least 13 in/Hg?All
Ye s®Go To 3
No®Repair leak or obstruction in vacuum hose as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 6.
214
DRIVEABILITY - GAS