P0693
DTC P0480, P0481, P0691, P0692, P0693, or P0694Diagnostic Instructions
^ Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure.
^ Review [Strategy Based Diagnosis] for an overview of the diagnostic approach. Strategy Based Diagnosis
^ [Diagnostic Procedure Instructions - Vehicle Diagnostic Information] provides an overview of each diagnostic category. Diagnostic Procedure Instructions - Vehicle Diagnostic Information
DTC Descriptors
DTC P0480 Cooling Fan Relay 1 Control Circuit
DTC P0481 Cooling Fan Relay 2 Control Circuit
DTC P0691 Cooling Fan Relay 1 Control Circuit Low Voltage
DTC P0692 Cooling Fan Relay 1 Control Circuit High Voltage
DTC P0693 Cooling Fan Relay 2 Control Circuit Low Voltage
DTC P0694 Cooling Fan Relay 2 Control Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Cooling Fan Relay
Circuit/System Description
The Cooling Fan Relay 1 or the Fan Low Relay, and the Cooling Fan Relay 3 or the Fan Hi Relay are controlled by the engine control module (ECM). Battery voltage is supplied to the cooling fan relay coil. The ECM monitors the voltage on the control circuit of the relay. When the relay is OFF, the voltage should be near battery voltage on the control circuit of the relay. When the relay is commanded ON, the voltage will be low on the control circuit of the relay. The ECM provides ground on the control circuit of the relay using a low side driver.
Conditions for Running the DTC
^ The ignition voltage is between 8-18 volts.
^ The engine speed is more than 40 RPM.
^ The ECM driver transitions from ON to OFF or from OFF to ON.
Conditions for Setting the DTC
P0480
The ECM detects an open on the low speed cooling fan relay control circuit for more then 1 second.
P0481
The ECM detects an open circuit on the high speed cooling fan relay control circuit for more then 1 second.
P0691
The ECM detects a short to ground on the low speed cooling fan relay control circuit for more then 1 second.
P0692
The ECM detects a short to voltage on the low speed cooling fan relay control circuit for more then 1 second.
P0693
The ECM detects a short to ground on the high speed cooling fan relay control circuit for more then 1 second.
P0694
The ECM detects a short to voltage on the high speed cooling fan relay control circuit for more then 1 second.
Action Taken When the DTC Sets
DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs.
Conditions for Clearing the MIL/DTC
DTCs P0480, P0481, P0691, P0692, 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 fan control command parameters on the scan tool to know which fans are being commanded ON by the ECM.
^ The following tables illustrate the FAN 1 relay, FAN 2 relay and the FAN 3 relay terminal locations in the underhood fuse block:
Circuit/System Verification
1. Ignition ON, command the appropriate fan relay ON and OFF with a scan tool. You should hear or feel the relay click.
2. If the vehicle passes the Circuit/System Verification test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.
Circuit/System Testing
P0480, P0691, or P0692
1. Ignition OFF, disconnect the fan relay 1.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal and ground.
If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition voltage circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
3. Connect a test lamp between the control circuit terminal and the ignition voltage circuit terminal.
4. Command the fan relay 1 ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
5. If all circuits test normal, test or replace the relay.
P0481, P0693, or P0694
1. Ignition OFF, disconnect both fan relay 2 and fan relay 3.
2. Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit of both relays and ground.
If the test lamp does not illuminate, test the applicable ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all components connected to the ignition voltage circuit and replace as necessary.
3. Test for 2.6 - 4.6 volts between the relay coil control circuit terminal of both fan relays and ground.
If less than the specified range, test the relay coil control circuit for an open/high resistance or for a short to ground. If the circuits/connections test normal, replace the ECM.
If greater than the specified range, test the relay coil control circuit for a short to voltage. If the circuits/connections test normal, replace the ECM.
4. Connect a test lamp between the relay coil control circuit and the relay coil ignition circuit of the HI SPEED Fan Relay.
5. Command the Fan Relays 2 and 3 ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
If the test lamp is always OFF, replace the ECM.
6. If all circuits test normal, test or replace the relay.
Component Testing
1. Measure for 70 - 110 ohms of resistance between terminals 85 and 86 of the relay.
If the resistance is not within the specified range, replace the relay.
2. Measure for infinite resistance between the following terminals of the relay:
^ 30 and 86
^ 30 and 87
^ 30 and 85
^ 85 and 87
If continuity is detected, replace the relay.
3. Connect a 20-amp fused jumper wire from the positive terminal of the battery to relay terminal 85. Connect a jumper wire from the negative terminal of the battery to relay terminal 86. Measure for less than 2 ohms between terminals 30 and 87 of the relay.
If the resistance measures more than the specified value, replace the relay.
Repair Instructions
Perform the [Diagnostic Repair Verification - Vehicle Diagnostic Information] after completing the diagnostic procedure.
^ [Relay Replacement (Within an Electrical Center)] [Relay Replacement (Attached to Wire Harness)]
^ [Control Module References] for ECM replacement, setup, and programming Programming and Relearning