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• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Relay Coil Ignition Circuit | P0480 04, P0481 04 | P0480 04, P0481 04 | - | - |
Relay Switch Ignition Circuit | * | * | - | - |
Fan Relay 1 Control Circuit | P0480 02 | P0480 04 | P0480 01 | P0480 54 |
Fan Relay 2 Control Circuit | P0481 02 | P0481 04 | P0481 01 | P0481 54 |
Fan Relay 3 Control Circuit | P0482 02 | P0482 04 | P0482 01 | P0482 54 |
Relay Controlled Output Control | * | * | ** | - |
*Fans inoperative without a DTC. **Fans always ON without a DTC. |
The engine control module (ECM) 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 ECM applies ground to the coil side of the low speed fan relay. This energises the coil and applies voltage directly to the main cooling fan through the switch side of the low relay. The main fan is connected in series to the auxiliary cooling fan through the de-energised series/parallel fan control relay. The series circuit operates both fans at low speed.
In high speed operation, the ECM applies a ground to the coil side of the low speed fan relay, the fan control relay, and the high speed fan relay. When energised, the high speed fan relay applies voltage directly to the auxiliary cooling fan through the switch side of the relay. Simultaneously, the low speed fan relay and the fan control relay provide ignition voltage and a direct path to ground for the main cooling fan. With both fans connected in a parallel circuit, each fan receives full voltage and operates at high speed.
• | The ignition is ON or the engine is running. |
• | The ignition voltage is greater than 10 V. |
• | The DTCs run continuously once the above conditions are met. |
The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 1 s.
DTCs P0480, P0481, and P0482 are Type C DTCs.
DTCs P0480, P0481, and P0482 are Type C DTCs.
Cooling System Description and Operation : 2.4L LAF → 2.0L Diesel LNP
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | 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 relay coil ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary. |
⇒ | If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module. |
⇒ | If the resistance is not within the specified range, replace the relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If not the specified range, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Relay Replacement : Within an Electrical Center → Attached to Wire Harness |
• | Control Module References for ECM replacement, setup, and programming |
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