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
- KM1 KOEO AND KOER DTCS P1460 OR P0645: VERIFY THAT ACCS PID IS OFF NOTE: Verify the AC and defrost were off during the KOEO/KOER self-tests. If the vehicle is not equipped with AC, the WAC circuit is not used and DTC P1460/P0645 can be ignored.
- Key on engine running.
- AC and defroster OFF.
- Access the PCM and monitor the ACCS PID.
Is the PID state OFF?
Yes No Key in OFF position
GO to KM2.ACCS input to PCM is requesting AC
REFER to the appropriate CLIMATE CONTROL SYSTEM article to the diagnose symptom. - KM2 CHECK THE VPWR VOLTAGE TO A/CC RELAY
- A/CC Relay connector disconnected.
- Key in ON position.
- Measure the voltage between:
( + ) A/CC Relay Connector, Harness Side ( - ) VPWR Ground Is the voltage greater than 10.5 V?
Yes No Key in OFF position
GO to KM3.REPAIR the open circuit
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
Rerun Self Test - KM3 CHECK THE A/CC RELAY
- REFER to the pin numbers molded on A/CC RELAY. Measure the resistance between either pin 1 or pin 85 and all the other pins of the relay. One measurement must be between 40 and 120 ohms, with the other measurements being greater than 10,000 ohms.
Are all the resistance checks OK?
Yes No GO to KM4. INSTALL a new A/CC relay
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
Rerun Self Test - KM4 CHECK THE A/CCR (WAC) CIRCUIT FOR A SHORT TO POWER IN THE HARNESS
- PCM connector disconnected.
- Key in ON position.
- Measure the voltage between:
( + ) A/CC Relay Connector, Harness Side ( - ) A/CCR Ground Is the voltage less than 1 V?
Yes No Key in OFF position
GO to KM5.REPAIR the short circuit
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
Rerun Self Test - KM5 CHECK THE A/CC (WAC) CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS
- Measure the resistance between:
( + ) A/CC Relay Connector, Harness Side ( - ) A/CCR Ground Is the resistance greater than 10K ohms?
Yes No GO to KM6. REPAIR the short circuit
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
Rerun Self Test - KM6 CHECK THE A/CC (WAC) CIRCUIT FOR AN OPEN IN THE HARNESS
- Measure the resistance between:
( + ) A/CC Relay Connector, Harness Side ( - ) PCM Connector, Harness Side A/CCR A/CCR Is the resistance less than 5 ohms?
Yes No INSTALL a new PCM.
Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
Rerun Self TestREPAIR the open circuit
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
Rerun Self Test - KM7 ACCS PID OFF WITH A/C ON: VERIFY THE A/C CLUTCH IS GETTING POWER
- Key on engine running.
- While listening for the A/C clutch to engage, turn the A/C on. If the clutch cannot be heard, disconnect the A/C clutch and connect a non-powered test lamp to the A/CC PWR and ground circuit to check for power.
Does the A/CC engage?
Yes No GO to KM8. REFER to the appropriate CLIMATE CONTROL SYSTEM article to the diagnose symptom. - KM8 CHECK THE ACCS CIRCUIT FOR AN OPEN IN THE HARNESS
- PCM connector disconnected.
- A/CC Assembly connector disconnected.
- Measure the resistance between:
( + ) PCM Connector, Harness Side ( - ) A/CC Assembly Connector, Harness Side A/CCS A/CC PWR Is the resistance less than 5 ohms?
Yes No INSTALL a new PCM.
Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .REPAIR the open circuit. - KM9 KOEO AND KOER DTC P1464: VERIFY THE A/C AND DEFROST WERE OFF DURING THE SELF-TEST
- Verify the A/C and defrost were off during the self-test.
Was the A/C and defrost off during the self-test?
Yes No For Vehicles with A/CC RLY
GO to KM10.
For All Others
GO to KM11.The A/CCS PID indicates an A/C OFF request is being sent to the PCM
Verify the test step results
A/C and defrost off
Rerun the self-test where the DTC P1464 was received. - KM10 CHECK THE ACCS PID
- Key in ON position.
- AC and defroster OFF.
- Access the PCM and monitor the ACCS PID.
Is the PID state ON?
Yes No Key in OFF position
The ACCS PID indicates that the PCM is being requested to turn on the A/C. ACCS
REFER to the appropriate CLIMATE CONTROL SYSTEM article to the diagnose symptom.The ACCS PID indicates that the ACCS input to the PCM is low
Verify the test step results
AC and defroster OFF
Rerun Self Test - KM11 CHECK THE ACCS PID
- Key in ON position.
- AC and defroster OFF.
- Access the PCM and monitor the ACCS PID.
Is the PID state ON?
Yes No Key in OFF position
GO to KM12.The ACCS PID indicates that the ACCS input to the PCM is low
Verify the test step results
AC and defroster OFF
Rerun Self Test - KM12 ACCS PID ON: DISCONNECT THE A/CCS AND CHECK IF THE ACCS PID TURNS OFF
- A/CCS Switch connector disconnected.
- Key in ON position.
- Access the PCM and monitor the ACCS PID.
Is the PID state OFF?
Yes No Verify operation of the A/CDSW
REFER to the appropriate CLIMATE CONTROL SYSTEM article to the diagnose symptom.Key in OFF position
GO to KM13. - KM13 CHECK THE A/CCS CIRCUIT FOR A SHORT TO POWER IN THE HARNESS
- PCM connector disconnected.
- Key in ON position.
- Measure the voltage between:
( + ) PCM Connector, Harness Side ( - ) A/CCS Ground Is the voltage less than 1 V?
Yes No INSTALL a new PCM.
Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .REPAIR the short circuit. - KM14 CONTINUOUS MEMORY DTCS P1460 OR P0645: CHECK THE A/CCR (WAC) CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS NOTE: If the vehicle is not equipped with AC, the WAC circuit is not used and the P1460/P0645 can be ignored.
- Key in ON position.
- CHECK the A/CCR (WAC) circuit for a short to ground while performing the following: (the A/C clutch clicks on when a fault is detected).
- Wiggle, shake, and bend small sections of the wiring harness while working from the component to the module.
- Lightly tap on the A/CC RLY to simulate road shock.
Is a fault indicated?
Yes No Key in OFF position
ISOLATE the fault and REPAIR as necessary
CLEAR the DTCs
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
REPEAT the self-test.GO to KM15. - KM15 CHECK THE A/CCR (WAC) FOR AN OPEN OR SHORT CIRCUIT TO POWER
- Key in ON position.
- Enter Output Test Mode. Refer to OUTPUT TEST MODE .
- Command the outputs ON.
- CHECK A/CCR (WAC) circuit for open or short to power while completing the following (the ACCS will click off when a fault is detected):
- Wiggle, shake, and bend small sections of the wiring harness while working from the component to the module.
- Lightly tap on the A/CC RLY to simulate road shock.
Is a fault indicated?
Yes No Key in OFF position
ISOLATE the fault and REPAIR as necessary
CLEAR the DTCs
Start Engine
Turn On AC Switch
Wait for 15 seconds
Turn Off AC Switch
REPEAT the self-test.Key in OFF position
Unable to duplicate or identify the fault at this time
GO to PINPOINT TEST Z step 1 .
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.