For 1990-2009 cars

## DTC P0691-P0694 Dual Fan

### 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 Descriptors

DTC P0691: Fan Control 1 Circuit Low Voltage
DTC P0692: Fan Control 1 Circuit High Voltage
DTC P0693: Fan Control 2 Circuit Low Voltage
DTC P0694: Fan Control 2 Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Fan Low Cooling Fan Relay Control Circuit | P0691 | P0691 | P0692 | --
Fan Low Cooling Fan Relay Coil Voltage Supply Circuit | P0691 | P0691 | -- | --
Fan High Cooling Fan Relay Control Circuit | P0693 | P0693 | P0694 | --
Fan High Cooling Fan Relay Coil Voltage Supply Circuit | P0693 | P0693 | -- | --

### Circuit/System Description

The engine control module (ECM) grounds the K2 relay, the K10 relay, and the K11 relay control circuits through an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line that is monitored by the ECM. When the ECM is commanding a component ON, the voltage potential of the control circuit should be low, near 0 volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. If the ECM detects that the actual state of the control circuit does not match the expected state, a DTC will set.

### Conditions for Running the DTCs

• | DTC P0606 is not set.

• | The system voltage is more than 9 volts.

• | The engine is running.

### Conditions for Setting the DTCs

• | An improper voltage level has been detected on the cooling fan relay control circuit.

• | The condition must be present for a minimum of 5 seconds.

### Action Taken When the DTC Sets

DTCs P0691, P0692, P0693 and P0694 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0691, P0692, P0693 and P0694 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

• | Master Electrical Component List

• | Component Connector End Views

#### Description and Operation

Cooling Fan Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Electrical Center Identification Views

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Ignition ON, command the cooling fans to High Speed, Low Speed, and OFF. Both cooling fans should turn on High Speed, Low Speed, and OFF when changing between the commanded states.

### Circuit/System Testing

1. Ignition OFF, disconnect all 3 cooling fan relays listed below:

• | K2 relay

• | K11 relay

• | K10 relay

2. Ignition ON, verify that a test lamp does not illuminate between each of the control circuit terminals listed below and ground:

• | K2 relay 87

• | K11 relay 87

• | K10 relay 87a

⇒ | If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the B+ circuit terminal 86 of each relay and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Verify that a test lamp illuminates between the B+ circuit terminal 30 of the K2 and K11 relays and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the appropriate cooling fan.

5. Disconnect the harness connector at each cooling fan.
6. Test for less than 2 ohms between the Engine Cooling Fan-Left ground circuit terminal A and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect a jumper wire between the K10 relay terminals 30 and 87 to complete the Engine Cooling Fan-Right ground.
8. Test for less than 2 ohms between the Engine Cooling Fan-Right ground control circuit terminal A and ground.

⇒ | If greater than the specified range, test the ground control circuit and fuse block ground circuit connector X1 terminal 5 for an open/high resistance. If the circuits test normal, test or replace the fuse block.

9. Connect the harness connectors at both cooling fans.
10. With the K10 relay jumper wire still in place, connect a 30A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87 of the K2 relay, then the K11 relay. Verify each cooling fan activates.

⇒ | If a cooling fan does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the cooling fan.

11. Turn the ignition OFF and allow the ECM to completely power down.
12. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85 of the K2 relay.
13. Ignition ON, command the low speed fan 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.

14. Turn the ignition OFF and allow the ECM to completely power down.
15. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85 of the K10 relay.
16. Ignition ON, command the high speed fans 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.

17. Turn the ignition OFF and allow the ECM to completely power down.
18. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85 of the K11 relay.
19. Ignition ON, command the high speed fans 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, test the control circuit for an open/high resistance.

20. If all circuits test normal, test or replace the appropriate relay listed below:

• | Engine Cooling Fan-Right inoperative on low speed only or high speed only-K10 relay

• | Engine Cooling Fan-Right inoperative on both low speed and high speed-K2 relay

• | Engine Cooling Fan-Left operates on low speed but not on high speed-K11 relay

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Engine Coolant Fan Motor Replacement

• | Control Module References

## DTC P0691-P0694 Single Fan

### 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 Descriptors

DTC P0691: Fan Control 1 Circuit Low Voltage
DTC P0692: Fan Control 1 Circuit High Voltage
DTC P0693: Fan Control 2 Circuit Low Voltage
DTC P0694: Fan Control 2 Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Low Speed Cooling Fan Relay Control Circuit | P0691 | P0691 | P0692 | --
Low Speed Cooling Fan Relay Coil Voltage Supply Circuit | P0691 | P0691 | -- | --
High Speed Cooling Fan Relay Control Circuit | P0693 | P0693 | P0694 | --
High Speed Cooling Fan Relay Coil Voltage Supply Circuit | P0693 | P0693 | -- | --

### Circuit/System Description

The engine control module (ECM) grounds the relay control circuits through an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line that is monitored by the ECM. When the ECM is commanding a component ON, the voltage potential of the control circuit should be low, near 0 volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. If the ECM detects that the actual state of the control circuit does not match the expected state, a DTC will set.

### Conditions for Running the DTC

• | The engine is running.

• | The system voltage is more than 9 volts.

• | DTC P0606 is not set.

### Conditions for Setting the DTCs

• | An improper voltage level has been detected on the cooling fan relay control circuit.

• | The condition must be present for a minimum of 30 seconds.

### Action Taken When the DTC Sets

DTCs P0691, P0692, P0693 and P0694 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0691, P0692, P0693 and P0694 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

• | Master Electrical Component List

• | Component Connector End Views

#### Description and Operation

Cooling Fan Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Electrical Center Identification Views

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Ignition ON, command each relay ON and OFF with a scan tool. Feel or listen to verify that each relay turns ON and OFF with each command.

### Circuit/System Testing

1. Ignition OFF, disconnect the appropriate relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.

⇒ | If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the ignition circuit terminal 30 and ground.

⇒ | If the test lamp does not illuminate, test the 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 control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the appropriate relay.

4. Verify that a test lamp illuminates between the ignition circuit terminal 86 and ground.

⇒ | If the test lamp does not illuminate, test the ignition circuit for an open/high resistance.

5. Disconnect the harness connector at the cooling fan.
6. Test for less than 1 ohm between the cooling fan ground circuit terminal 1 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the cooling fan.
8. Connect a 20A fused jumper wire between the ignition circuit terminal 86 and the control circuit terminal 87. Verify the cooling fan is activated.

⇒ | If the cooling fan does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the cooling fan.

9. Connect a test lamp between the ignition circuit terminal 30 and the control circuit terminal 85.
10. Clear the DTCs with a scan tool.
11. Command the appropriate relay 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.

12. If all circuits test normal, test or replace the appropriate relay.

### Component Testing

#### Relay Test

1. Ignition OFF, disconnect the appropriate relay.
2. Test for 75-90 ohms between terminals 85 and 86.

⇒ | If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 30 and 86

• | 30 and 87

• | 30 and 85

• | 85 and 87

⇒ | If not the specified value, replace the relay.

4. Test for less than 1 ohm between terminals 30 and 87A.

⇒ | If greater than the specified range, replace the relay.

5. Install a 5A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 1 ohm between terminals 30 and 87.

⇒ | If greater than the specified range, replace the relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Engine Coolant Fan Motor Replacement

• | Auxiliary Engine Coolant Fan and Fan Motor Replacement

• | Control Module References