Cooling Fan Inoperative 1.8L RPO-LAY
Diagnostic Instructions
Circuit/System Description
The fan 1 relay provides power to the fan control module. The fan control module completes the fan motor circuit by providing a path to ground. The module energizes the fan and controls fan speed according to instructions received from the powertrain
control module (PCM).
Diagnostic Aids
| • | The fan relay electrical contacts may be pitted or sticking. Replace the relay, if tapping gently on the relay, or wiggling the relay causes a change in the relays operation. |
| • | The performance of the cooling relay may be affected by temperature. Check the relay after sitting outside overnight and after running the engine 30 minutes. |
Use the following relay cavity table in order to locate the correct cavities to probe during diagnosis. The table layout corresponds to the cavity layout of the relay block.
Cooling Fan 1 Relay
Terminal Identification
|
Relay Coil Ignition
| Relay Controlled Output
| Relay Switch B+
|
Relay Coil Control
|
Front of Vehicle
|
Reference Information
Schematic Reference
Engine Cooling Schematics
Connector End View Reference
Component Connector End Views
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
- Verify the HVAC system operates correctly.
- Ignition ON, command the cooling fan ON and OFF with a scan tool. Verify that the fan turns ON and OFF when changing between the commanded states.
Circuit/System Testing
- Ignition OFF, disconnect the PCM connector X1.
- Ignition ON, verify the cooling fan turns ON.
| ⇒ | If the fan is ON, replace the PCM. |
| ⇒ | If the fan is OFF, test the PCM fan control circuit for a short to ground. |
- Ignition OFF, remove the cooling fan 1 relay.
- Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit terminal 1 and ground.
| ⇒ | If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. |
- Connect a test lamp between the relay coil control circuit terminal 2 and the relay coil ignition circuit terminal 1. Verify the test lamp illuminates.
| ⇒ | If the test lamp does not illuminate, repair the open/high resistance in the relay coil control circuit. |
- Verify the test lamp illuminates between the relay switch B+ circuit terminal 3 and ground.
| ⇒ | If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the RDI FAN fuse is open, test the relay controlled output circuit terminal 5 for a short
to ground. If the circuit tests normal, test or replace the relay. |
- Ignition OFF, disconnect the fan control module (FCM).
- Connect a 20A fused jumper between the relay switch B+ circuit terminal 3 and the relay controlled output circuit terminal 5 of the fan 1 relay.
- Ignition ON, connect a test lamp to the FCM harness connector terminal 1. Verify the test lamp illuminates.
| ⇒ | If the test lamp does not illuminate, test the relay controlled output circuit for an open/high resistance. |
- Ignition OFF, disconnect the cooling fan electrical connector.
- Connect a 30A fused jumper between B+ and the cooling fan terminal 2.
- Connect a 30A fused jumper between ground and the cooling fan terminal 1. Verify the fan turns ON.
| ⇒ | If the fan is ON, test the FCM ground circuit terminal 3 for an open/high resistance. If the circuit tests normal, replace the FCM. |
| ⇒ | If the fan is OFF, test the cooling fan motor circuits for an open/high resistance. If the circuit tests normal, replace the cooling fan. |
Component Testing
- Ignition OFF, disconnect the relay.
- Test for 85-120 ohms at 20°C (68°F) between terminals 1 and 2.
| ⇒ | If the resistance is not within the specified range, replace the relay. |
- Test for infinite resistance between the following terminals:
| ⇒ | If not the specified range, replace the relay. |
- Install a 20A fused jumper wire between relay terminal 1 and 12 volts. Install a jumper wire between relay terminal 2 and ground. Test for less than 2 ohms between terminals 3 and 5.
| ⇒ | If greater than the specified range, replace the relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
Cooling Fan Inoperative 2.4L RPO-LAX
Diagnostic Instructions
Circuit/System Description
The powertrain control module (PCM) commands the fans ON in either high speed or low speed, depending on cooling requirements. In low speed, both fans are turned ON at a reduced speed. High speed has both fans turned ON at full speed.
In low speed operation, the PCM applies ground to the coil side of the low speed fan 3 relay. This energizes the coil and applies voltage directly to the auxiliary cooling fan through the switch side of the fan 3 relay. The fan is connected
in series to the main cooling fan through the de-energized series/parallel (S/P) fan control 2 relay. The series circuit operates both fans at low speed.
In high speed operation, the PCM applies a ground to the coil side of the low speed fan 3 relay, the S/P fan 2 relay, and the high speed fan 1 relay. When energized, the high speed fan 1 relay applies voltage directly to the
main cooling fan through the switch side of the relay. Simultaneously, the low speed fan 3 relay and the S/P fan 2 relay provide ignition voltage and a direct path to ground for the auxiliary cooling fan. With both fans connected in a parallel
circuit, each fan receives full voltage and operates at high speed.
Diagnostic Aids
| • | The fan relay electrical contacts may be pitted or sticking. Replace the relay, if tapping gently on the relay, or wiggling the relay causes a change in the relays operation. |
| • | The performance of the relay may be affected by temperature. Check the relay after sitting outside overnight and after running the engine 30 minutes. |
Use the following relay cavity table in order to locate the correct cavities to probe during diagnosis. The table layout corresponds to the cavity layout of the relay block.
Cooling Fan 1 Relay
Terminal Identification
|
Relay Coil Ignition
| Relay Controlled Output
| Relay Switch B+
|
Relay Coil Control
|
Front of Vehicle
|
Cooling Fan 2 Relay
Terminal Identification
|
Relay Controlled Input
| Ground
| Relay Coil Control
|
Relay Controlled Output
|
Relay Coil Ignition
|
Front of Vehicle
|
Cooling Fan 3 Relay
Terminal Identification
|
Relay Controlled Output
| Relay Switch B+
| Relay Coil Control
|
Relay Coil Ignition
|
Front of Vehicle
|
Reference Information
Schematic Reference
Engine Cooling Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Cooling Fan Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the fans ON and OFF with a scan tool. Verify that the fans turn ON and OFF when changing between the commanded states.
Circuit/System Testing
- Ignition OFF, remove the cooling fan relays.
Important: The following test must be performed on all cooling fan relay circuits.
- Ignition ON, verify that a test lamp illuminates between the relay coil ignition circuit terminal 1 and ground.
| ⇒ | If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. |
- Connect a test lamp between the fan relay coil control circuit terminal 2 and the relay coil ignition circuit terminal 1.
- Command the cooling fan relays 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 does not turn ON and OFF, test the relay coil control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PCM. |
- Connect a 30A fused jumper between the relay controlled input circuit terminal 3 and the ground circuit terminal 5 at the S/P fan 2 relay connector. This will complete the auxiliary fan ground circuit. Leave this jumper in place
for the remainder of this procedure.
Important: The following test must be performed on both the high speed fan 1 relay circuit and the low speed fan 3 relay circuit.
- Ignition ON, verify that a test lamp illuminates between ground and the relay switch B+ circuit terminals as listed below:
| ⇒ | If the test lamp does not illuminate, test the appropriate relay switch B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay switch 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 relay. |
Important: The following test must be performed first on the high speed fan 1 relay circuit and next on the low speed fan 3 relay circuit. Leave the jumper connected to the low speed fan relay circuit for the next
test.
- Connect a 30A fused jumper between the relay switch B+ circuit terminal and the relay controlled output circuit terminal as listed below. Verify the appropriate fan is activated.
| • | Fan 1 relay terminal 3 and terminal 5 |
| • | Fan 3 relay terminal 5 and terminal 3 |
| ⇒ | If the appropriate fan does not activate, test the relay controlled output circuit for a short to ground or an open/high resistance. If the circuit tests normal, test the fan ground circuit for an open/high resistance. If the circuit tests normal,
replace the fan. |
- Install the S/P fan 2 relay. Verify both fans activate at low speed.
| ⇒ | If both fans do not activate, test the relay controlled output circuit terminal 4 of the S/P fan 2 relay for a short to ground or an open/high resistance. |
- If all circuits test normal, test or replace the relay.
Component Testing
- Ignition OFF, disconnect the relay.
- Test for 85-120 ohms at 20°C (68°F) between terminals 1 and 2.
| ⇒ | If the resistance is not within the specified range, replace the relay. |
- Test for infinite resistance between the following terminals:
| ⇒ | If not the specified range, replace the relay. |
- Test for less than 2 ohms between terminals 3 and 4.
| ⇒ | If greater than the specified range, replace the relay. |
- Install a 20A fused jumper wire between relay terminal 1 and 12 volts. Install a jumper wire between relay terminal 2 and ground. Test for less than 2 ohms between terminals 3 and 5.
| ⇒ | If greater than the specified range, replace the relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
