Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0691 00: Cooling Fan Relay 1 Control Circuit Low VoltageDTC P0692 00: Cooling Fan Relay 1 Control Circuit High Voltage
DTC P0693 00: Cooling Fan Relay 2 Control Circuit Low Voltage
DTC P0694 00: Cooling Fan Relay 2 Control Circuit High Voltage
Diagnostic Fault Information
KR20A Cooling Fan Medium Speed 1 Relay
Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance |
|---|---|---|---|---|---|
Relay Coil Ignition Circuit | P0691 00, P0693 00 | P0691 00, P0693 00 | P0691 00, P0693 00 | -- | -- |
Relay Switch B+ Circuit | 1 | 1 | 1 | -- | -- |
Relay Control Circuit | P0693 00 | P0693 00 | P0693 00 | P0694 00 | -- |
Relay Controlled Output Circuit | 2 | 2 | 2 | 3 | -- |
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KR20B Cooling Fan Medium Speed Relay
Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance |
|---|---|---|---|---|---|
Relay Coil Ignition Circuit | P0691 00, P0693 00 | P0691 00, P0693 00 | P0691 00, P0693 00 | -- | -- |
Relay Switch B+ Circuit | 1 | 2 | 2 | -- | -- |
Relay Control Circuit | 3 | 4 | 4 | -- | -- |
Relay Controlled Output Circuit | 2 | 2 | 2 | 3 | -- |
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KR20D Cooling Fan High Speed Relay
Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance |
|---|---|---|---|---|---|
Relay Coil Ignition Circuit | P0693 00 | P0693 00 | P0693 00 | -- | -- |
Relay Switch B+ Circuit | 2 | 2 | 2 | -- | -- |
Relay Control Circuit | P0693 00 | 2 | P0693 00 | 1 | -- |
Relay Controlled Output Circuit | P0693 00 | 2 | P0693 00 | 3 | -- |
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KR20E Cooling Fan Speed Control Relay
Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance |
|---|---|---|---|---|---|
Relay Coil Ignition Circuit | P0691 00, P0693 00 | 1 | 1 | -- | -- |
Relay Switch Ignition Circuit | P0693 00 | 1 | P0693 00 | -- | -- |
Relay Control Circuit | 2 | 1 | 1 | -- | -- |
Relay Controlled Output Circuit | P0693 00 | 1 | P0693 00 | 4 | -- |
| |||||
KR20F Cooling Fan Relay
Circuit | Short to Ground | High Resistance | Open | Short to voltage | Signal Performance |
|---|---|---|---|---|---|
Relay Coil Ignition Circuit | P0691 00, P0693 00 | 3 | P0691 00, P0693 00 | -- | -- |
Relay Switch Ground Circuit | 2 | 3 | 3 | 3 | -- |
Relay Control Circuit | P0691 00 | 1 | P0691 00 | P0692 00 | -- |
Relay Controlled Output Circuit | -- | 1 | 1 | 1 | -- |
| |||||
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 fan is turned ON at a higher reduced speed. In high speed, the fan is turned ON at full speed. In low speed operation, the ECM provides ground to ECM terminal 51 (X1). The cooling fan relay activates and provides ground to the coils of the cooling fan medium speed 2 relay and the cooling fan speed control relay. The cooling fan speed control relay activates and provides power to the coil of the cooling fan high speed relay. The cooling fan high speed relay remains inactive because ECM terminal 71 (X2) is not grounded. The cooling fan medium speed 2 relay provides power to the engine cooling fan motor through cooling fan terminal 3 and the internal fan resistor. In medium speed operation, the ECM provides ground to ECM terminal 71 (X2). The cooling fan high speed relay remains inactive because power is not provided to the coil from the cooling fan speed control relay. The cooling fan medium speed 1 relay activates and provides power to the engine cooling fan motor through cooling fan terminal 2 and the internal fan resistor. In high speed operation, the ECM provides ground to ECM terminals 51 (X1) and 71 (X2). As previously described, power is now provided to both cooling fan terminals 2 and 3. In addition, power and ground are now provided to the coil of the cooling fan high speed relay. The cooling fan high speed relay activates and provides power to the engine cooling fan motor through cooling fan terminal 4, bypassing the resistors.
Conditions for Running the DTC
| • | The ignition voltage is between 8-18 V. |
| • | The engine is running greater than or equal to 400 RPM. |
Conditions for Setting the DTC
P0691 00
The ECM detects a short to ground or open circuit on the cooling fan relay control circuit for more than 1 s.
P0692 00
The ECM detects a short to voltage on the cooling fan relay control circuit for more than 1 s.
P0693 00
The ECM detects a short to ground or open circuit on the cooling fan high speed relay control circuit for more than 1 s.
P0694 00
The ECM detects a short to voltage on the cooling fan high speed relay control circuit for more than 1 s.
Action Taken When the DTC Sets
DTCs P0691 00, P0692 00, P0693 00and P0694 00 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0691 00, P0692 00, P0693 00and P0694 00 are Type B DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Command the Cooling Fan Relay 1ON and OFF with a scan tool. The fan should turn ON at low speed and OFF with each command.
- Command the Cooling Fan Relay 2 ON and OFF with a scan tool. The fan should turn ON at medium speed and OFF with each command.
- Command the Cooling Fan Relay 3 ON and OFF with a scan tool. The fan should turn ON at high speed and OFF with each command.
| ⇒ | If the fan does not operate correctly, go to low speed operation malfunction. |
| ⇒ | If the fan does not operate correctly, go to medium speed operation malfunction. |
| ⇒ | If the fan does not operate correctly, go to high speed operation malfunction. |
Circuit/System Testing
Note: Circuit/System Verification must be performed before Circuit/System Testing or misdiagnosis may result.
Low Speed Malfunction
- Ignition OFF, disconnect the relays listed below:
- Ignition ON, verify that a test lamp does not illuminate between relay controlled output circuit terminal of the relay connectors listed below and ground:
- Test for less than 1.0 Ω between the relay controlled output circuit terminal of the KR20F Cooling Fan Relay and ground.
- Verify that a test lamp illuminates between the relay coil ignition circuit terminal of each relay connector listed below and ground:
- Verify that a test lamp illuminates between the relay switch B+ circuit terminal of the KR20B Cooling Fan Medium Speed Relay connector and ground.
- Install a 10 A fused jumper wire between the relay coil ignition circuit terminal and the relay coil control circuit terminal of the KR20B Cooling Fan Medium Speed Relay connector.
- Verify that a test lamp illuminates between the relay switch ignition circuit terminal and the relay controlled output circuit terminal at the KR20F Cooling Fan Relay connector.
- Disconnect the harness connector at the G10 Cooling Fan Motor.
- Test for less than 1.0 Ω between the G10 Cooling Fan Motor ground circuit terminal 1 and ground.
- Connect the harness connector at the G10 Cooling Fan Motor.
- Connect a 60 A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal of the KR20B Cooling Fan Medium Speed Relay connector. Verify the cooling fan is activated at low speed.
- Verify that a test lamp does not illuminate between the relay coil control circuit terminal of the KR20F Cooling Fan Relay connector and ground.
- Test for 70-110 Ω between terminals 85 and 86 of the KR20F Cooling Fan Relay.
- Ignition OFF, connect a 10 A fused jumper wire between the relay coil ignition circuit terminal at the KR20F Cooling Fan Relay connector and terminal 85 at the KR20F Cooling Fan Relay.
- Connect a DMM set on the 10 A scale between the relay coil control circuit terminal at the KR20F Cooling Fan Relay connector and terminal 86 at the KR20F Cooling Fan Relay.
- Command the Fan Relay 1 OFF with a scan tool. The DMM should indicate less than 1 mA
- Command the Fan Relay 1 ON with a scan tool. The DMM should indicate more than 100 mA.
- If all circuits test normal, test the relays listed below for correct operation and replace the faulty relay.
| • | KR20B Cooling Fan Medium Speed Relay |
| • | KR20E Cooling Fan Speed Control Relay |
| • | KR20F Cooling Fan Relay |
| • | KR20B Cooling Fan Medium Speed Relay |
| • | KR20E Cooling Fan Speed Control Relay |
| ⇒ | If the test lamp illuminates, test the output circuit for a short to voltage. |
| ⇒ | If greater than the specified range, test the output circuit for an open/high resistance. |
| • | KR20B Cooling Fan Medium Speed Relay |
| • | KR20F Cooling Fan Relay |
| ⇒ | If the test lamp does not illuminate, test the relay coil 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 the relay switch controlled output circuit terminal at the KR20E Cooling Fan Speed Control Relay connector for a short to ground. If the circuit tests normal, test or replace the KR20E Cooling Fan Speed Control Relay. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay controlled output circuit terminal at the relay connectors listed below for a short to ground: |
| • | KR20B Cooling Fan Medium Speed Relay |
| • | KR20F Cooling Fan Relay |
| ⇒ | If the test lamp does not illuminate, test the relay switch ignition circuit terminal at the KR20F Cooling Fan Relay connector for an open/high resistance. |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the cooling fan does not activate at low speed, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the cooling fan. |
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If not within the specified range, replace the relay. |
| ⇒ | If greater than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
| ⇒ | If less than the specified range, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
| • | KR20B Cooling Fan Medium Speed Relay |
| • | KR20F Cooling Fan Relay |
Medium Speed Malfunction
- Ignition OFF, disconnect the KR20A Cooling Fan Medium Speed Relay.
- Ignition ON, verify that a test lamp does not illuminate between the relay controlled output circuit terminal and ground.
- Verify that a test lamp illuminates between the relay coil ignition circuit terminal and ground.
- Verify that a test lamp illuminates between the relay switch B+ circuit terminal and ground.
- Connect a 60 A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal. Verify the cooling fan is activated at medium speed.
- Test for less than 1 V between the relay coil control circuit terminal and ground.
- Test for 70-110 Ω between terminals 85 and 86 of the KR20A Cooling Fan Medium Speed Relay.
- Ignition OFF, connect a 10 A fused jumper wire between the relay coil ignition circuit terminal at the KR20A Cooling Fan Medium Speed Relay connector and terminal 85 at the KR20A Cooling Fan Medium Speed Relay.
- Connect a DMM set on the 10 A scale between the relay coil control circuit terminal at the KR20A Cooling Fan Medium Speed Relay connector and terminal 86 at the KR20A Cooling Fan Medium Speed Relay.
- Command the Fan Relay 1 and 2 OFF with a scan tool. The DMM should indicate less than 1 mA.
- If less than the specified range, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
- If all circuits test normal, test or replace the KR20A Cooling Fan Medium Speed Relay.
| ⇒ | If the test lamp illuminates, test the output circuit for a short to voltage. |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
| ⇒ | If the cooling fan does not activate, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the G10 Cooling Fan Motor. |
| ⇒ | If more than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, test the KR20E Cooling Fan Speed Control Relay for correct operation. If the relay tests normal, replace the K20 Engine Control Module. |
| ⇒ | If not within the specified range, replace the KR20A Cooling Fan Medium Speed Relay. |
| ⇒ | If greater than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
High Speed Malfunction
- Ignition OFF, disconnect the relays listed below:
- Ignition ON, verify that a test lamp does not illuminate between the relay controlled output circuit terminal at the KR20D Cooling Fan High Speed Relay connector and ground.
- Verify that a test lamp illuminates between the relay coil ignition circuit terminal of the KR20E Cooling Fan Speed Control Relay connector and ground.
- Verify that a test lamp illuminates between the relay switch ignition circuit terminal of the KR20E Cooling Fan Speed Control Relay connector and ground.
- Install a 10 A fused jumper wire between the relay switch ignition circuit terminal and the relay controlled output circuit terminal of the KR20E Cooling Fan Speed Control Relay connector.
- Verify that a test lamp illuminates between the relay coil ignition circuit terminal of the KR20D Cooling Fan High Speed Relay connector and ground.
- Verify that a test lamp illuminates between the relay switch B+ circuit terminal of the KR20D Cooling Fan High Speed Relay connector and ground.
- Connect a 60 A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal of the KR20D Cooling Fan High Speed Relay connector. Verify the cooling fan is activated at high speed.
- Ignition OFF, remove the KR20A Cooling Fan Medium Speed Relay.
- Test for less than 5 Ω between the relay coil control circuit terminals at the relay connectors listed below:
- If all circuits test normal, test the relays listed below for correct operation and replace the faulty relay.
| • | KR20D Cooling Fan High Speed Relay |
| • | KR20E Cooling Fan Speed Control Relay |
| ⇒ | If the test lamp illuminates, test the output circuit for a short to voltage. |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the ignition circuit terminal for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the relay controlled output circuit for a short to ground. If the circuit tests normal, test or replace the G10 Cooling Fan Motor. |
| ⇒ | If the cooling fan does not activate at high speed, test the output circuit for an open/high resistance. If the circuit tests normal, test or replace the G10 Cooling Fan Motor. |
| • | KR20A Cooling Fan Medium Speed Relay |
| • | KR20D Cooling Fan High Speed Relay |
| ⇒ | If more than the specified range, test the KR20D Cooling Fan High Speed Relay coil control circuit for and open/high resistance. |
| • | KR20D Cooling Fan High Speed Relay |
| • | KR20E Cooling Fan Speed Control Relay |
Component Testing
Dynamic Test
- Ignition OFF, disconnect the applicable relay.
- Test for 70-110 Ω between terminals 85 and 86 of the relay.
- Test for infinite resistance between the following terminals:
- Test for less than 2 Ω between terminals 30 and 87A.
- 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 the resistance is not within the specified range, replace the relay. |
| • | 30 and 86 |
| • | 30 and 87 |
| • | 30 and 85 |
| • | 85 and 87 |
| • | 30 and 86 |
| ⇒ | If not the specified value, replace the relay. |
| ⇒ | If more than the specified value, replace the relay. |
| ⇒ | If more than the specified value, replace the relay. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Engine Control Module Replacement for ECM replacement, setup, and programming |
