P0693
DTC P0481, P0693, or P0694 (LFW, LFX)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0481
- Cooling Fan Relays 2 and 3 Control Circuit
DTC P0693
- Cooling Fan Relays 2 and 3 Control Circuit Low Voltage
DTC P0694
- Cooling Fan Relays 2 and 3 Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The engine cooling fan system is composed of one cooling fan, a series of 5 relays, the engine control module (ECM), and the associated wiring. The cooling fan assembly includes two individual resistors mounted to each side of the cooling fan shroud. This combination of components enables the ECM to operate the cooling fan at 3 speeds using two fan control circuits.
To operate the fan, the ECM activates the applicable relay by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.
Conditions for Running the DTC
* The ignition voltage is greater than 11 volts.
* The ECM driver transitions from ON to OFF or from OFF to ON.
* DTCs P0481, P0693, and P0694 run continuously when the conditions above are met.
Conditions for Setting the DTC
The commanded state of the ECM driver and actual state of the control circuit do not match for greater than 5 seconds.
Action Taken When the DTC Sets
DTCs P0481, P0693, and P0694 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0481, P0693, and P0694 are Type B DTCs.
Diagnostic Aids
* The ECM has the capability of providing command to the fan relays even when a scan tool output control is being used. Always refer to the scan tool Cooling Fan Relay Command parameters to know which fans are being commanded ON by the ECM.
* The scan tool cooling fan output control operates as follows:
- Cooling Fan Relay 1 operates the fan at a low speed
- Cooling Fan Relay 2 and 3 operates the fan at a medium speed
- Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed
* When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the correct orientation in the fuse block. Test the mating electrical terminals for tightness.
Reference Information
Schematic Reference
Engine Cooling Schematics [1][2]Cooling System
Connector End View Reference
* Component Connector End Views Connector End Views By Name
* Electrical Center Identification Views X50A Fuse Block - Underhood Label
Description and Operation
Cooling Fan Description and Operation (LF1, LFW, LFX) Cooling Fan Description and Operation (LF1, LFW, LFX)
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, command the cooling fan ON and OFF in low, medium and high speed, with a scan tool. Verify that the cooling fan operates at the correct speed in each of the commanded states.
2. Engine operating, observe the DTC information with a scan tool. Verify DTC P0480, P0691, or P0692 is not set.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, disconnect the KR20 cooling fan relays listed below:
* KR20P COOL FAN 2 Relay 9
* KR20D COOL FAN 1 Relay 13
2. Ignition ON, verify that a test lamp illuminates between ground and the KR20P relay coil ignition circuit terminal 86.
• If the test lamp does not illuminate, test the relay coil ignition circuit for an open/high resistance.
Note: The following tests must be performed on each relay control circuit.
3. Connect the red lead of the DMM to a control circuit terminal listed below. Connect the black lead to ground. Set the DMM on the diode setting. The DMM should display OL.
* KR20P COOL FAN 2 relay terminal 85
* KR20D COOL FAN 1 relay terminal 86
• If less than the specified range, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
Note:
* A short to voltage may cause the cooling fan driver to over heat and turn OFF. Turn the ignition OFF for 30 seconds to allow the driver to cool, then retest if the control function does not operate.
* The following test must be performed on each relay control circuit.
4. Command the cooling fan relay ON and OFF at high speed, with a scan tool. The DMM should transition from OL when commanded OFF to less than 1 V when commanded ON.
* KR20P COOL FAN 2 relay terminal 85
* KR20D COOL FAN 1 relay terminal 86
• If the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or for a short to voltage. If the circuit tests normal, replace the K20 ECM.
5. If all circuits test normal, test or replace the appropriate KR20 relay.
Component Testing
1. Ignition OFF, disconnect the KR20 cooling fan relay.
2. Test for 60-100 ohm between terminals 85 and 86.
• If not within the specified range, replace the KR20 cooling fan relay.
3. Measure the resistance between the terminals listed below. The DMM should display OL.
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If less than the specified range, replace the KR20 cooling fan relay.
4. Connect a 20 A fused jumper wire between relay terminal 85 and B+. Connect a jumper wire between relay terminal 86 and ground. Test for less than 2 ohm between terminals 30 and 87.
• If greater than the specified range, replace the KR20 cooling fan relay.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)
* Control Module References Control Module References for ECM replacement, setup, and programming