Cooling Fan Inoperative (LPL or LPV)
Diagnostic Instructions
Diagnostic Fault Information
Cooling Fan Low Speed Relay
Circuit
|
Short to Ground
|
High Resistance
|
Open
|
Short to Voltage
|
Signal Performance
|
Relay Coil Ignition
|
P0691
|
P0691
|
P0691
|
-
|
-
|
Relay Switch B+
|
1
|
1
|
1
|
-
|
-
|
Relay Coil Control
|
P0691
|
P0691
|
P0691
|
P0692
|
-
|
Relay Output Control
|
1
|
1
|
1
|
2
|
-
|
1. Fan Inoperative Without a DTC.
2. Fan Always ON Without a DTC.
|
|
| |
Cooling Fan Medium Speed Relay (w/AC), Cooling Fan High Speed
(w/o AC)
Circuit
|
Short to Ground
|
High Resistance
|
Open
|
Short to Voltage
|
Signal Performance
|
Relay Coil Ignition
|
P0693
|
P0693
|
P0693
|
-
|
-
|
Relay Switch B+
|
1
|
1
|
1
|
-
|
-
|
Relay Coil Control
|
P0693
|
P0693
|
P0693
|
P0694
|
-
|
Relay Output Control
|
1
|
1
|
1
|
2
|
-
|
1. Fan Inoperative Without a DTC.
2. Fan Always ON Without a DTC.
|
|
| |
Cooling Fan High Speed Relay (w/AC)
Circuit
|
Short to Ground
|
High Resistance
|
Open
|
Short to Voltage
|
Signal Performance
|
Relay Coil Ignition
|
P0695
|
P0695
|
P0695
|
-
|
-
|
Relay Switch B+
|
1
|
1
|
1
|
-
|
-
|
Relay Coil Control
|
P0695
|
P0695
|
P0695
|
P0696
|
-
|
Relay Output Control
|
1
|
1
|
1
|
2
|
-
|
1. Fan Inoperative Without a DTC.
2. Fan Always ON Without a DTC.
|
|
| |
Circuit/System Description
The engine control module (ECM) commands the fans ON in either
high speed, medium speed, or low speed, depending on cooling
requirements.
Low Speed
In low speed operation, the ECM applies ground to the coil side of
the cooling fan low speed relay with the cooling fan relay 1
control circuit.
This energizes the relay coil. The low speed cooling fan relay
supply power to the cooling fan motor through an internal fan
resistor.
Medium Speed
In medium speed operation, the ECM commands the medium speed fan
relay on. This energizes the relay coil. The medium speed cooling
fan relay supply power to the cooling fan motor through an internal
fan resistor. The cooling fan is connected to a dedicated ground,
and operates at medium speed.
High Speed
In high speed operation, the ECM applies a ground to the coil side
of all the high speed cooling fan relay. When energized, the high
speed relays apply voltage directly to the cooling fan through the
switch side of the relay.
Reference Information
Schematic Reference
Engine Cooling Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Cooling System Description and Operation
Electrical Information Reference
Circuit/System Verification
Cooling Fan Inoperative with AC
| 1. |
Verify that DTC P0116, P0117
or P0118 is not present. |
| 2. |
Command the Cooling Fan Relay
1 ON and OFF with a scan tool. The cooling fan motor should turn ON
at low speed and OFF when changing between the commanded
states. |
| ⇒ |
If the cooling fan motor does not operate
correctly, refer to Cooling Fan Inoperative with AC. |
| 3. |
Command the Cooling Fan Relay
2 ON and OFF with a scan tool. The cooling fan motor should turn ON
at medium speed and OFF when changing between the commanded
states. |
| ⇒ |
If the cooling fan motor does not operate
correctly, refer to Cooling Fan Inoperative with AC. |
| 4. |
Command the Cooling Fan Relay
3 ON and OFF with a scan tool. The cooling fan motor should turn ON
at high speed and OFF when changing between the commanded
states. |
| ⇒ |
If the cooling fan motor does not operate
correctly, refer to Cooling Fan Inoperative with AC. |
Cooling Fan Inoperative without AC
| 1. |
Verify that DTC P0116, P0117
or P0118 is not present. |
| 2. |
Command the Cooling Fan Relay
1 ON and OFF with a scan tool. The cooling fan motor should turn ON
at low speed and OFF when changing between the commanded
states. |
| ⇒ |
If the cooling fan motor does not operate
correctly, refer to Cooling Fan Inoperative without AC. |
| 3. |
Command the Cooling Fan Relay
2 ON and OFF with a scan tool. The cooling fan motor should turn ON
at medium speed and OFF when changing between the commanded
states. |
| ⇒ |
If the cooling fan motor does not operate
correctly, refer to Cooling Fan Inoperative without AC. |
Circuit/System Testing
Cooling Fan Inoperative with AC
| 1. |
Ignition OFF, disconnect the
relays listed below: |
| |
• |
KR20B Cooling Fan Medium Speed
2 Relay |
| |
• |
KR20C Cooling Fan Low Speed
Relay |
| |
• |
KR20D Cooling Fan High Speed
Relay |
| 2. |
Ignition ON, verify that a
test lamp illuminates between the circuit terminals listed below
and ground. |
| |
• |
KR20B Cooling Fan Medium Speed
2 Relay ignition circuit terminal 86 |
| |
• |
KR20C Cooling Fan Low Speed
Relay ignition circuit terminal 86 |
| |
• |
KR20C Cooling Fan Low Speed
Relay B+ circuit terminal 30 |
| |
• |
KR20D Cooling Fan High Speed
Relay ignition circuit terminal 86 |
| |
• |
KR20D Cooling Fan High Speed
Relay B+ circuit terminal 30 |
| ⇒ |
If the test lamp does not illuminate, replace the
X50A Fuse Block - Underhood. |
| 3. |
Verify that a test lamp
illuminates between the KR20B Cooling Fan Medium Speed 2 Relay B+
circuit terminal 30 and ground. |
| ⇒ |
If the test lamp does not illuminate, test the B+
circuit for an open/high resistance. If the circuit tests normal,
replace the X50A Fuse Block - Underhood. |
| 4. |
Connect a test lamp between
the terminals listed below and command the appropriate Cooling Fan
Relay ON with a scan tool. The test lamp should illuminate.
|
| |
• |
KR20C Cooling Fan Low Speed
Relay ignition circuit terminal 86 and the control circuit terminal
85 |
| |
• |
KR20B Cooling Fan Medium Speed
2 Relay ignition circuit terminal 86 and the control circuit
terminal 85 |
| |
• |
KR20D Cooling Fan High Speed
Relay ignition circuit terminal 86 and the control circuit terminal
85 |
| ⇒ |
If the test lamp does not illuminate, test the
control circuit for a short to voltage or an open/high resistance.
If the circuit tests normal, replace the K20 Engine Control
Module. |
| 5. |
Ignition OFF, disconnect the
harness connector at the G10 Cooling Fan Motor. |
| 6. |
Verify that a test lamp
illuminates between the ground circuit terminal 1 and B+.
|
| ⇒ |
If the test lamp does not illuminate, test the
ground circuit for an open/high resistance. |
| 7. |
Connect the harness connector
at the G10 Cooling Fan Motor. |
| 8. |
Install a 60 A fused jumper
wire between the terminals listed below and verify the G10 Cooling
Fan Motor is activated. |
| |
• |
KR20B Cooling Fan Medium Speed
2 Relay B+ circuit terminal 30 and the control circuit terminal
87 |
| |
• |
KR20C Cooling Fan Low Speed
Relay B+ circuit terminal 30 and the control circuit terminal
87 |
| |
• |
KR20D Cooling Fan High Speed
Relay B+ circuit terminal 30 and the control circuit terminal
87 |
| ⇒ |
If the G10 Cooling Fan Motor is not activated,
test the control circuit for a short to ground or an open/high
resistance. If the circuit tests normal, replace the G10 Cooling
Fan Motor. |
| 9. |
If all circuit tests normal,
test or replace the appropriate cooling fan relay. |
Cooling Fan Inoperative without AC
| 1. |
Ignition OFF, disconnect the
relays listed below: |
| |
• |
KR20C Cooling Fan Low Speed
Relay |
| |
• |
KR20D Cooling Fan High Speed
Relay |
| 2. |
Ignition ON, verify that a
test lamp illuminates between the circuit terminals listed below
and ground. |
| |
• |
KR20C Cooling Fan Low Speed
Relay ignition circuit terminal 86 |
| |
• |
KR20C Cooling Fan Low Speed
Relay B+ circuit terminal 30 |
| |
• |
KR20D Cooling Fan High Speed
Relay ignition circuit terminal 86 |
| |
• |
KR20D Cooling Fan High Speed
Relay B+ circuit terminal 30 |
| ⇒ |
If the test lamp does not illuminate, replace the
X50A Fuse Block - Underhood. |
| 3. |
Connect a test lamp between
the terminals listed below and command the appropriate Cooling Fan
Relay ON with a scan tool. The test lamp should illuminate.
|
| |
• |
KR20C Cooling Fan Low Speed
Relay ignition circuit terminal 86 and the control circuit terminal
85 |
| |
• |
KR20D Cooling Fan High Speed
Relay ignition circuit terminal 86 and the control circuit terminal
85 |
| ⇒ |
If the test lamp does not illuminate, test the
control circuit for a short to voltage or an open/high resistance.
If the circuit tests normal, replace the K20 Engine Control
Module. |
| 4. |
Ignition OFF, disconnect the
harness connector at the G10 Cooling Fan Motor. |
| 5. |
Verify that a test lamp
illuminates between the ground circuit terminal 1 and B+.
|
| ⇒ |
If the test lamp does not illuminate, test the
ground circuit for an open/high resistance. |
| 6. |
Connect the harness connector
at the G10 Cooling Fan Motor. |
| 7. |
Install a 60 A fused jumper
wire between the terminals listed below and verify the G10 Cooling
Fan Motor is activated. |
| |
• |
KR20C Cooling Fan Low Speed
Relay B+ circuit terminal 30 and the control circuit terminal
87 |
| |
• |
KR20D Cooling Fan High Speed
Relay B+ circuit terminal 30 and the control circuit terminal
87 |
| ⇒ |
If the G10 Cooling Fan Motor is not activated,
test the control circuit for a short to ground or an open/high
resistance. If the circuit tests normal, replace the G10 Cooling
Fan Motor. |
| 8. |
If all circuit tests normal,
test or replace the appropriate cooling fan relay. |
Component Testing
Dynamic Test
| 1. |
Ignition OFF, disconnect the
applicable relay. |
| 2. |
Test for 70-110 Ω
between terminals 85 and 86 of the relay. |
| ⇒ |
If the resistance is not within the specified
range, replace the relay. |
| 3. |
Test for infinite resistance
between the following terminals: |
| ⇒ |
If not the specified value, replace the relay. |
| 4. |
Install a 20 A fused jumper
wire between relay terminal 85 and 12 V. Install a jumper wire
between relay terminal 86 and ground. Test for less than 2 Ω
between terminals 30 and 87. |
| ⇒ |
If greater than the specified value, replace the
relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
