Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test Procedure
- KF1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS) P0480, P0481 AND P0482
Are any of the following DTCs present during PCM self-test P0480, P0481, or P0482?
Yes No For KOEO and KOER DTC P0480, GO to KF2.
For KOEO and KOER DTC P0481, GO to KF12.
For KOEO and KOER DTC P0482, GO to KF7.
For continuous memory DTC P0480, GO to KF17.
For continuous memory DTC P0481, GO to KF19.
For continuous memory DTC P0482, GO to KF21.For cooling fan always runs, GO to KF23.
For cooling fan does not operate, GO to KF24. - KF2 KOEO AND KOER DTC P0480: CHECK THE VPWR VOLTAGE TO LOW SPEED FC RELAY
- LFC Relay connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) LFC Relay Connector, Harness Side (-) Vehicle Battery VPWR - Pin 2 Negative terminal
Is the voltage greater than 10.5 V?
Yes No GO to KF3. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - KF3 CHECK FOR LFC CIRCUIT CYCLING NOTE: During KOEO on demand self-test, the LFC circuit will be cycled on and off.
- Connect a non-powered test lamp between:
Point A LFC Relay Connector, Harness Side Point B LFC Relay Connector, Harness Side VPWR - Pin 2 LFC - Pin 1 - Carry out the PCM KOEO on demand self-test.
Does the test lamp illuminate on and off during the KOEO on demand self-test?
Yes No INSTALL a new LFC relay. CLEAR the DTCs. REPEAT the self-test. REMOVE the test lamp.
GO to KF4. - Connect a non-powered test lamp between:
- KF4 CHECK THE LFC CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
- Ignition OFF.
- PCM connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) LFC Relay Connector, Harness Side (-) Vehicle Battery LFC - Pin 1 Negative terminal
Is the voltage less than 1 V?
Yes No GO to KF5. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. - KF5 CHECK THE LFC CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Measure the resistance between:
(+) LFC Relay Connector, Harness Side (-) Vehicle Battery LFC - Pin 1 Negative terminal
Is the resistance greater than 10K ohms?
Yes No GO to KF6. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- KF6 CHECK THE LFC CIRCUIT FOR AN OPEN IN THE HARNESS
- Measure the resistance between:
(+) LFC Relay Connector, Harness Side (-) PCM Connector, Harness Side LFC - Pin 1 LFC - Pin B34
Is the resistance less than 5 ohms?
Yes No GO to KF30. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- KF7 KOEO AND KOER DTC P0482: CHECK THE VPWR VOLTAGE TO MEDIUM SPEED FC RELAY
- MFC Relay connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) MFC Relay Connector, Harness Side (-) VPWR - Pin 2 Ground
Is the voltage greater than 10.5 V?
Yes No GO to KF8. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - KF8 CHECK FOR MFC CIRCUIT CYCLING NOTE: During KOEO on demand self-test, the MFC circuit will be cycled on and off.
- Connect a non-powered test lamp between:
Point A MFC Relay Connector, Harness Side Point B MFC Relay Connector, Harness Side VPWR - Pin 2 MFC - Pin 1 - Carry out the PCM KOEO on demand self-test.
Does the test lamp illuminate on and off during the KOEO on demand self-test?
Yes No INSTALL a new MFC relay. CLEAR the DTCs. REPEAT the self-test. REMOVE the test lamp.
GO to KF9. - Connect a non-powered test lamp between:
- KF9 CHECK THE MFC CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
- Ignition OFF.
- PCM connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) MFC Relay Connector, Harness Side (-) MFC - Pin 1 Ground
Is the voltage less than 1 V?
Yes No GO to KF10. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. - KF10 CHECK THE MFC CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Ignition OFF.
- Measure the resistance between:
(+) MFC Relay Connector, Harness Side (-) MFC - Pin 1 Ground
Is the resistance greater than 10K ohms?
Yes No GO to KF11. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. - KF11 CHECK THE MFC CIRCUIT FOR AN OPEN IN THE HARNESS
- Measure the resistance between:
(+) MFC Relay Connector, Harness Side (-) PCM Connector, Harness Side MFC - Pin 1 MFC - Pin B18
Is the resistance less than 5 ohms?
Yes No GO to KF30. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- KF12 KOEO AND KOER DTC P0481: CHECK THE VPWR VOLTAGE TO THE HIGH SPEED FC RELAY
- HFC Relay connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) HFC Relay Connector, Harness Side (-) VPWR - Pin 2 Ground
Is the voltage greater than 10.5 V?
Yes No GO to KF13. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - KF13 CHECK FOR HFC CIRCUIT CYCLING NOTE: During KOEO on demand self-test, the HFC circuit will be cycled on and off.
- Connect a non-powered test lamp between:
Point A HFC Relay Connector, Harness Side Point B HFC Relay Connector, Harness Side VPWR - Pin 2 HFC - Pin 1 - Carry out the KOEO on demand self-test.
Does the test lamp illuminate on and off during the KOEO on demand self-test?
Yes No INSTALL a new HFC relay. CLEAR the DTCs. REPEAT the self-test. REMOVE the test lamp.
GO to KF14. - Connect a non-powered test lamp between:
- KF14 CHECK THE HFC CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
- PCM connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) HFC Relay Connector, Harness Side (-) Vehicle Battery HFC - Pin 1 Negative terminal
Is the voltage less than 1 V?
Yes No GO to KF15. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. - KF15 CHECK THE HFC CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Measure the resistance between:
(+) HFC Relay Connector, Harness Side (-) Vehicle Battery HFC - Pin 1 Negative terminal
Is the resistance greater than 10K ohms?
Yes No GO to KF16. REPAIR the short circuit. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- KF16 CHECK THE HFC CIRCUIT FOR AN OPEN IN THE HARNESS
- Measure the resistance between:
(+) HFC Relay Connector, Harness Side (-) PCM Connector, Harness Side HFC - Pin 1 HFC - Pin B36
Is the resistance less than 5 ohms?
Yes No GO to KF30. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - Measure the resistance between:
- KF17 CONTINUOUS MEMORY DTC P0480: CHECK THE LFC CIRCUIT FOR AN INTERMITTENT OPEN OR SHORT TO VOLTAGE
- A/C and defrost off.
- Left Fan Motor connector disconnected.
- Right Fan Motor connector disconnected.
- Connect a non-powered test lamp between:
Point A Left Fan Motor Connector, Harness Side Point B Left Fan Motor Connector, Harness Side LSFAN PWR - Pin 1, 2 GND - Pin 3 - Ignition ON, engine OFF.
- Enter Output Test Mode. Refer to OUTPUT TEST MODE (OTM) .
- Command the low speed fan ON.
- Observe the test lamp for an indication of a concern while carrying out the following. Note that the lamp turns off when a concern is detected.
- Shake, wiggle, and bend the LFC circuit(s).
- Shake, wiggle, and bend the VPWR circuit to the LFC relay.
- Lightly tap on the low speed FC relay to simulate road shock
Is a concern present?
Yes No ISOLATE the concern and REPAIR as necessary. GO to KF18. - KF18 CHECK THE LFC CIRCUIT FOR AN INTERMITTENT SHORT TO GROUND
- Ignition ON, engine OFF.
- Command the outputs OFF
- Observe the test lamp for an indication of a concern while completing the following. Note that the lamp turns on when a concern is detected.
- Shake, wiggle, and bend the LFC circuit(s).
- Lightly tap on the LFC relay to simulate road shock
Is a concern present?
Yes No ISOLATE the concern and REPAIR as necessary. Unable to duplicate or identify the concern at this time.
GO to PINPOINT TEST Z . - KF19 CONTINUOUS MEMORY DTC P0481: CHECK THE HFC CIRCUIT FOR AN INTERMITTENT OPEN OR SHORT TO VOLTAGE
- A/C and defrost off.
- Left Fan Motor connector disconnected.
- Right Fan Motor connector disconnected.
- Connect a non-powered test lamp between:
Point A Right Fan Motor Connector, Harness Side Point B Right Fan Motor Connector, Harness Side HSFAN PWR - Pin 2 GND - Pin 1 - Ignition ON, engine OFF.
- Enter Output Test Mode. Refer to OUTPUT TEST MODE (OTM) .
- Command the high speed fan ON.
- Observe the test lamp for an indication of a concern while completing the following. Note that the lamp turns on when a concern is detected.
- Shake, wiggle, and bend the HFC circuit(s).
- Shake, wiggle, and bend the VPWR circuit to the HFC relay.
- Lightly tap on the high speed FC relay to simulate road shock
Is a concern present?
Yes No ISOLATE the concern and REPAIR as necessary. GO to KF20. - KF20 CHECK THE HFC CIRCUIT FOR AN INTERMITTENT SHORT TO GROUND
- Ignition ON, engine OFF.
- Command the outputs OFF
- Observe the test lamp for an indication of a concern while completing the following. Note that the lamp turns on when a concern is detected.
- Shake, wiggle, and bend the HFC circuit(s).
Is a concern present?
Yes No ISOLATE the concern and REPAIR as necessary. Unable to duplicate or identify the concern at this time.
GO to PINPOINT TEST Z . - KF21 CONTINUOUS MEMORY DTC P0482: CHECK THE MFC CIRCUIT FOR AN INTERMITTENT OPEN OR SHORT TO VOLTAGE
- A/C and defrost off.
- Left Fan Motor connector disconnected.
- Right Fan Motor connector disconnected.
- Connect a non-powered test lamp between:
Point A Right Fan Motor Connector, Harness Side Point B Right Fan Motor Connector, Harness Side MSFAN PWR - Pin 2 GND - Pin 1 - Ignition ON, engine OFF.
- Enter Output Test Mode. Refer to OUTPUT TEST MODE (OTM) .
- Command the low speed fan ON.
- Observe the test lamp for an indication of a concern while carrying out the following. Note that the lamp turns off when a concern is detected.
- Shake, wiggle, and bend the MFC circuit(s).
- Shake, wiggle, and bend the VPWR circuit to the MFC relay.
- Medium speed FC relay low speed FC relay
Is a concern present?
Yes No ISOLATE the concern and REPAIR as necessary. GO to KF22. - KF22 CHECK THE MFC CIRCUIT FOR AN INTERMITTENT SHORT TO GROUND
- Ignition ON, engine OFF.
- Command the outputs OFF
- Observe the test lamp for an indication of a concern while completing the following. Note that the lamp turns off when a concern is detected.
- Shake, wiggle, and bend the MFC circuit(s).
Is a concern present?
Yes No ISOLATE the concern and REPAIR as necessary. Unable to duplicate or identify the concern at this time.
GO to PINPOINT TEST Z . - KF23 COOLING FAN ALWAYS RUNS (NO DTCS): VERIFY THE FAN IS NOT ON BECAUSE OF A/C PRESSURE SWITCH (A/CP) INPUT TO THE PCM NOTE: The cooling fans can run when high engine cooling system temperature are present.
- Air conditioning or defrost off.
- Ignition ON, engine running.
- Access the PCM and monitor the AC_REQ PID.
Is the PID state no?
Yes No GO to KF24. REFER to the DIAGNOSIS AND TESTING , to DIAGNOSE the air conditioning is always on.
CLEAR the DTCs. REPEAT the self-test. - KF24 CHECK THE VPWR VOLTAGE TO LOW SPEED FC RELAY
- LFC Relay connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) LFC Relay Connector, Harness Side (-) Vehicle Battery VPWR - Pin 2 Negative terminal
Is the voltage greater than 10.5 V?
Yes No GO to KF25. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - KF25 CHECK FOR LFC CIRCUIT CYCLING NOTE: During KOEO on demand self-test, the LFC circuit will be cycled on and off.
- Connect a non-powered test lamp between:
Point A LFC Relay Connector, Harness Side Point B LFC Relay Connector, Harness Side VPWR - Pin 2 LFC - Pin 1 - Carry out the PCM KOEO on demand self-test.
Does the test lamp illuminate on and off during the KOEO on demand self-test?
Yes No GO to KF26. REMOVE the test lamp.
GO to KF4. - Connect a non-powered test lamp between:
- KF26 CHECK THE VPWR VOLTAGE TO MEDIUM SPEED FC RELAY
- Ignition OFF.
- MFC Relay connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) MFC Relay Connector, Harness Side (-) VPWR - Pin 2 Ground
Is the voltage greater than 10.5 V?
Yes No GO to KF27. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - KF27 CHECK FOR MFC CIRCUIT CYCLING NOTE: During KOEO on demand self-test, the MFC circuit will be cycled on and off.
- Connect a non-powered test lamp between:
Point A MFC Relay Connector, Harness Side Point B MFC Relay Connector, Harness Side VPWR - Pin 2 MFC - Pin 1 - Carry out the PCM KOEO on demand self-test.
Does the test lamp illuminate on and off during the KOEO on demand self-test?
Yes No GO to KF28. REMOVE the test lamp.
GO to KF9. - Connect a non-powered test lamp between:
- KF28 CHECK THE VPWR VOLTAGE TO HIGH SPEED FC RELAY
- Ignition OFF.
- HFC Relay connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
(+) HFC Relay Connector, Harness Side (-) VPWR - Pin 2 Ground
Is the voltage greater than 10.5 V?
Yes No GO to KF29. REPAIR the open circuit. CLEAR the DTCs. REPEAT the self-test. - KF29 CHECK FOR HFC CIRCUIT CYCLING NOTE: During KOEO on demand self-test, the HFC circuit will be cycled on and off.
- Connect a non-powered test lamp between:
Point A HFC Relay Connector, Harness Side Point B HFC Relay Connector, Harness Side VPWR - Pin 2 HFC - Pin 1 - Carry out the KOEO on demand self-test.
Does the test lamp illuminate on and off during the KOEO on demand self-test?
Yes No The PCM primary FC circuits are OK.
REFER to the appropriate SYSTEM WIRING DIAGRAMS article to check the relay(s).
INSTALL a new FC relay if necessary.
To check the secondary FC circuits,
REFER to the DIAGNOSIS AND TESTING .REMOVE the test lamp.
GO to KF14. - Connect a non-powered test lamp between:
- KF30 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
- pushed out pins.
- corrosion.
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test and verify the concern is still present.
Is the concern still present?
Yes No INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) . The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.