PRE-RELEASE
DTC P1484
| DTC P1484 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptor |
DTC P1484 00
Cooling Fan System Performance
| Diagnostic Fault Information |
Cooling Fan Left High Speed Relay
| Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance | ||||||
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Relay Coil Ignition
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P0691 00
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P0691 00
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P0480 00
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-
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-
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Relay Switch B+
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1
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1
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1
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-
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-
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Relay Coil Control
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P0691 00
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P0691 00
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P0480 00
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P0692 00
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P1484 00
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||||||
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Relay Output Control
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1
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1
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1
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2
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-
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||||||
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|||||||||||
Cooling Fan Left Low Speed Relay, Cooling Fan Speed Control Relay and Cooling Fan Right Low Speed Relay
| Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance | ||||||
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Relay Coil Ignition Circuit
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P0693 00
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P0693 00
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P0481 00
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-
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-
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||||||
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Relay Switch B+ Circuit
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1
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1
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1
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-
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-
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||||||
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Relay Coil Control Circuit
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P0693 00
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P0693 00
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P0481 00
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P0694 00
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P1484 00
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||||||
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Relay Controlled Output Circuit
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1
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1
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1
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2
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-
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||||||
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Cooling Fan Medium Speed Relay
| Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance | ||||||
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Relay Coil Ignition Circuit
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P0695 00
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P0695 00
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P0482 00
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-
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-
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||||||
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Relay Switch B+ Circuit
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1
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1
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1
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-
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-
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||||||
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Relay Coil Control Circuit
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P0695 00
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P0695 00
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P0482 00
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P0696 00
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P1484 00
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Relay Controlled Output Circuit
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1
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1
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1
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2
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-
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||||||
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| Circuit/System Description |
The engine control module (ECM) commands the fan ON in either high speed, medium speed, or low speed, depending on cooling requirements. In low speed, the fan is turned ON at a reduced speed. In medium speed, the fans are turned ON at a higher reduced speed. In high speed, the fans are turned ON at full speed. In low speed operation, the ECM provides ground to ECM terminal 94 X2. The cooling fan relay activates and provides ground to the coil of the cooling fan left high speed relay. The cooling fan speed control relay remains inactive because ECM terminal 90 X2 is not grounded. The cooling fan left high speed relay provides power to the engine cooling fan right through engine cooling fan left and the internal fan resistor of engine cooling fan right.
In medium speed operation, the ECM provides ground to ECM terminal 90 X2. The cooling fan left low speed, cooling fan speed control relay and the cooling fan right low speed relay are activated. The internal fan resistor of the engine cooling fan left is provided with power through the cooling fan left low speed relay. The cooling fan speed control relay is active and therefore the engine cooling fan left terminal 3 is directly shorted to ground. The cooling fan right low speed relay is active and provides power to the internal resistor of the engine cooling fan right. The engine cooling fan right terminal 3 is directly shorted to ground. Both fans runs with medium speed.
In high speed operation, the ECM provides ground to ECM terminals 90 X2, 91 X2 and 94 X2. Cooling fan left high speed relay, cooling fan medium speed 1 relay, cooling fan left low speed relay, cooling fan speed control relay and cooling fan right low speed relay are activated. Power is now provided to both cooling fan terminals 1. The engine cooling fan relay left is directly shorted to ground through the cooling fan speed control relay. The engine cooling fan right is directly shorted to ground. In this constellation both fans run without resistor.
Conditions for Running the DTC
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The ignition voltage is between 8-18 V.
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The engine is running greater than or equal to 400 RPM.
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| Conditions for Setting the DTC |
The ECM detects an over current at the output powerstage.
| Action Taken When the DTC Sets |
DTC P1484 00 is a Type A DTC.
| Conditions for Clearing the DTC |
DTC P1484 00 is a Type A DTC.
| Reference Information |
Schematic Reference
Engine Cooling Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Cooling Fan Description and Operation (Diesel) Cooling Fan Description and Operation (LDK/A20NHT, LBW/A28NER, LAU/A28NET )
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
| 1. |
Command the Cooling Fan Relay 1 ON and OFF with a scan tool. The clicking sound of the relay should be heard when changing between the commanded states.
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| 2. |
If the relay does not operate correctly, refer to Cooling Fan Left High Speed Output Malfunction.
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| 3. |
Command the Cooling Fan Relay 2 ON and OFF with a scan tool. The clicking sound of the relay should be heard when changing between the commanded states.
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| 4. |
If the relay does not operate correctly, refer to Cooling Fan Left Low Speed Output Malfunction.
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| 5. |
Command the Cooling Fan Relay 3 ON and OFF with a scan tool. The clicking sound of the relay should be heard when changing between the commanded states.
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| 6. |
If the relay does not operate correctly, refer to Cooling Fan Medium Speed Output Malfunction.
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| Circuit/System Testing |
Cooling Fan Left High Speed Output Malfunction
| 1. |
Ignition OFF, disconnect the KR20J Cooling Fan Left High Speed Relay.
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| 2. |
Ignition ON, verify that a test lamp does not illuminate between the relay coil control circuit terminal and ground.
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| 3. |
If the test lamp illuminates, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
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| 4. |
Ignition OFF, disconnect the K20 Engine Control Module. Test for an infinite resistance between the relay coil control circuit terminal and ground.
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| 5. |
If less than the specified value, test the relay coil control circuit for a short to ground.
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| 6. |
Test for less than 5.0 Ω between relay coil control circuit terminal and K20 Engine Control Module terminal 94 X2.
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| 7. |
If greater than the specified value, test the relay coil control circuit for an open/high resistance.
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| 8. |
Test for 70-110 Ω between 85 and 86 of the KR20J Cooling Fan Left High Speed Relay.
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| 9. |
If the resistance is not within the specified range, replace the KR20J Cooling Fan Left High Speed Relay.
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Cooling Fan Left Low Speed Output Malfunction
| 1. |
Ignition OFF, disconnect the KR20G Cooling Fan Left Low Speed Relay.
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| 2. |
Ignition ON, verify that a test lamp does not illuminate between the relay coil control circuit terminal and ground.
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| 3. |
If the test lamp illuminates, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
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| 4. |
Ignition OFF, disconnect the K20 Engine Control Module. Test for an infinite resistance between the relay coil control circuit terminal and ground.
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| 5. |
If less than the specified value, test the relay coil control circuit for a short to ground.
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| 6. |
Test for less than 5.0 Ω between relay coil control circuit terminal and K20 Engine Control Module terminal 94 X2.
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| 7. |
If greater than the specified value, test the relay coil control circuit for an open/high resistance.
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| 8. |
Test for 70-110 Ω between terminals 85 and 86 of the KR20G Cooling Fan Left Low Speed Relay.
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| 9. |
If the resistance is not within the specified range, replace the KR20G Cooling Fan Left Low Speed Relay.
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Cooling Fan Medium Speed Output Malfunction
| 1. |
Ignition OFF, disconnect the KR20A Cooling Fan Medium Speed 1 Relay.
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| 2. |
Ignition ON, verify that a test lamp does not illuminate between the relay coil control circuit terminal and ground.
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| 3. |
If the test lamp illuminates, test the relay coil control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
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| 4. |
Ignition OFF, disconnect the K20 Engine Control Module. Test for an infinite resistance between the relay coil control circuit terminal and ground.
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| 5. |
If less than the specified value, test the relay coil control circuit for a short to ground.
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| 6. |
Test for less than 5.0 Ω between relay coil control circuit terminal and K20 Engine Control Module terminal 94 X2.
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| 7. |
If greater than the specified value, test the relay coil control circuit for an open/high resistance.
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| 8. |
Test for 70-110 Ω between terminals 85 and 86 of the KR20A Cooling Fan Medium Speed 1 Relay.
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| 9. |
If the resistance is not within the specified range, replace the KR20A Cooling Fan Medium Speed 1 Relay.
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| Component Testing |
Dynamic Test
| 1. |
Ignition OFF, disconnect the applicable relay.
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| 2. |
Test for 70-110 Ω between terminals 85 and 86 of the relay.
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| 3. |
If the resistance is not within the specified range, replace the relay.
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| 4. |
Test for infinite resistance between the following terminals:
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30 and 86
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30 and 87
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30 and 85
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85 and 87
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30 and 86
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If not the specified value, replace the relay.
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| 5. |
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.
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| 6. |
If more than the specified value, replace the relay.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Relay Replacement (Attached to Wire Harness)
Relay Replacement (Within an Electrical Center)
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Control Module References
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| Repair Verification |
| 1. |
Ignition ON, verify with a scan tool that the ECM is not commanding fan activation.
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| 2. |
Ignition ON, observe that the fan is not activated.
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