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Test Km: Wot A/C Cut-Off: Testing

WARNING: This page does not describe the selected car, but rather 25 other vehicles, including the 2002 Lincoln Town Car, 2002 Lincoln Navigator, 2002 Lincoln LS, 2002 Lincoln Continental, and 2002 Lincoln Blackwood. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION  table of fault code setting condition.
FAULT CODE SETTING CONDITION

Fault Code KOEO KOER Continuous Memory
P1460  KM1  KM1  KM30
P1464  KM19  KM19  
    NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: Ensure A/C and defroster were off during KOEO and/or KOER self-test. If vehicle is not equipped with A/C, disregard DTC P1460. DTC P1460 can be set if A/C or defroster were on during KOEO or KOER self-test.

  1. 1) KOEO & KOER DTC P1460: Verify ACCS PID Is OFF
    DTC P1460 is set when an excessive current draw is detected when PCM grounds Wide Open Throttle A/C Cut-Off (WAC) circuit, or voltage is not detected on WAC circuit when PCM interrupts ground on WAC circuit. Possible causes are:
    • Open Or Shorted WAC Circuit
    • Faulty WAC Relay (Or CCRM)
    • Open VPWR Circuit To WAC Relay
    • Faulty PCM

    If A/C or defroster was on during self-test, turn system off and repeat self-test. Ensure A/C and defroster are off during self-test. If KOEO or KOER DTC P1460 is present, start engine and allow to idle. Using scan tool, access ACCS PID from PID/DATA MONITOR & RECORD menu. If ACCS PID indicates OFF, go to next step. If ACCS PID indicates ON, ACCS input to PCM is requesting A/C. Diagnose A/C ALWAYS ON under SYMPTOM TESTS in appropriate A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.

  2. 2) Check VPWR Voltage To WAC Relay

    Turn ignition switch to OFF position. Remove WAC relay. For WAC relay locations, refer to WIDE OPEN THROTTLE A/C CUTOFF RELAY LOCATIONS  table. Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and VPWR cavity (IGN RUN on Continental) at WAC relay. See Figure-Figure . If voltage is more than 10.5 volts, go to next step. On LS and Thunderbird, if voltage is 10.5 volts or less, go to TEST B, step 5) , or repair open in VPWR (or IGN RUN) circuit (all others). See A/C wiring diagram in appropriate A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair.
    3. NOTE: Different applications will use an ISO micro relay or ISO mini relay for a WAC relay. For relay identification, refer to illustrations. See Figure or Figure .

  3. 3) Check WAC Relay
    Turn ignition switch to OFF position and proceed as follows:

    • ISO Mini Relay

      Measure resistance between relay terminal No. 85 and 86. Resistance should be 40-120 ohms. Measure resistance between terminals No. 85 and all other relay terminals. Resistance should be more than 10 k/ohms. See Figure.

    • ISO Micro Relay

      Measure resistance between relay terminal No. 1 and 2. Resistance should be 40-120 ohms. Measure resistance between terminals No. 1 and all other relay terminals. Resistance should be more than 10 k/ohms. See Figure.

    On either relay, if resistance is as specified, go to next step. If relay resistance is not as specified, replace WAC relay. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair.

  4. 4) Check WAC Circuit For Short To PWR In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and WAC circuit at WAC relay cavity. See Figure or Figure and Figure-Figure . If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in WAC circuit. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair.

  5. 5) Check WAC Circuit For Short To Ground In Harness

    Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between chassis ground and WAC circuit at WAC relay cavity. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in WAC circuit. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair.

  6. 6) Check WAC Circuit For Open In Harness

    Using a DVOM, measure resistance of WAC circuit between PCM harness connector and WAC relay cavity. See Figure or Figure and Figure-Figure . If resistance is less than 5 ohms, replace PCM. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair. If resistance is 5 ohms or more, repair open in WAC circuit. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 6) to step 10). No test procedures have been omitted.
    7. NOTE: Diagnostic procedures beginning with step  10) are performed when directed here from LOW IDLE WITH A/C ON (Econoline 4.6L, 5.4L and 6.8L only) symptom under SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V - GASOLINE & NGV article.

  7. 10) ACCS PID OFF With A/C On: Verify A/C Clutch Is Getting PWR
    Start engine and allow to idle. Listen for A/C clutch to engage while turning A/C on. If clutch can be heard engaging, go to next step. If A/C clutch cannot be heard, turn ignition switch to OFF position. Disconnect A/C clutch connector. Connect test light between PWR and GND circuits at A/C clutch harness connector. Again, start engine and allow to idle. Turn A/C on. If test light illuminates, PWR is being supplied to A/C clutch, but ACCS PID value reads OFF. Go to next step. If test light does not illuminate, ACCS PID is OFF due to PWR not being supplied to A/C clutch. A/C clutch is not cause of low idle symptom. Return to LOW IDLE WITH A/C ON under SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V - GASOLINE & NGV article to continue diagnosing low idle concern. Repair as necessary. If a low idle symptom is not the concern and A/C clutch operates normally, see appropriate A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.

  8. 11) Check ACCS Circuit For Open In Harness

    Turn ignition switch to OFF position. Disconnect A/C clutch connector, if not done previously. Disconnect PCM connector. Inspect connectors for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of ACCS circuit between PCM harness connector and A/C clutch harness connector. See Figure and Figure . If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in ACCS circuit between A/C clutch and PCM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 11) to step 19). No test procedures have been omitted.
    9. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: Ensure both A/C and defroster were off during KOEO and KOER self-test. If either A/C or defroster were on during self-test, turn system off and repeat self-test.

  9. 19) KOEO & KOER DTC P1464: Check ACCS PID
    DTC P1464 can be set if A/C or defroster is on during KOEO or KOER self-test. DTC P1464 is set when ACCS input to PCM was high during self-test. Possible causes for this fault are:
    • A/C On During Self-Test
    • Short To VPWR In A/C Clutch VPWR Circuit (Applications With Normally Closed WAC Relay)
    • ACCS Circuit Shorted To PWR
    • Faulty A/C Demand Switch
    • Faulty WAC Relay (Or CCRM)
    • Faulty PCM

    Turn ignition switch to ON position. Using scan tool, access ACCS PID from PID/DATA MONITOR & RECORD menu. If ACCS PID value indicates ON, go to next step (Econoline except 4.2L), go to appropriate A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING to diagnose A/C ALWAYS ON symptom (all others). If ACCS PID value indicates OFF, this indicates that ACCS input to PCM is low. Verify self-test results. Leave A/C and defroster off and repeat QUICK TEST .

  10. 20) ACCS PID ON: Disconnect A/C Cycling Switch & Check If ACCS PID Indicates OFF

    Turn ignition switch to OFF position. Disconnect A/C cycling switch. Turn ignition switch to ON position. Using scan tool, access ACCS PID from PID/DATA MONITOR & RECORD menu. If ACCS PID indicates ON, go to next step. If ACCS PID value indicates OFF, check operation of A/C demand switch. See appropriate A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. Repair as necessary. If A/C demand switch is okay, repair short to PWR in A/C demand circuit to A/C cycling switch.

  11. 21) Check ACCS Circuit For Short To PWR In Harness

    Turn ignition switch to OFF position. Disconnect PCM connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and ACCS circuit at PCM harness connector. See Figure and Figure . If voltage is less than one volt, replace PCM. If voltage is one volt or more, repair short to PWR in ACCS circuit. Verify symptom is no longer present.
    12. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: If vehicle is not equipped with A/C, WAC circuit is not used and DTC P1460 can be ignored.

  12. 30) Continuous Memory DTC P1460: Check WAC Circuit For Intermittent Short To Ground
    DTC P1460 is set when an excessive current draw is detected when PCM grounds Wide Open Throttle A/C Cut-Off (WAC) circuit, or voltage is not detected on WAC circuit when PCM interrupts ground on WAC circuit. Possible causes are:
    • Open Or Shorted WAC Circuit
    • Faulty WAC Relay (Or CCRM)
    • Open VPWR Circuit To WAC Relay
    • Faulty PCM

    Ensure A/C is off. Turn ignition switch to ON position. Check WAC circuit for short to ground (fault will be indicated by A/C clicking on) while performing the following:

    • Shake, wiggle and bend WAC circuit between PCM and WAC relay. See Figure-Figure .
    • Lightly tap on WAC relay to simulate road shock.

    If no faults are found, go to next step. If any faults are found, isolate fault and repair as necessary. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair.

  13. 31) Check WAC Circuit For Intermittent Open Or Short To PWR

    Ensure ignition switch is turned to ON position. Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command ALL OUTPUTS ON. Check WAC circuit for open or short to PWR (fault will be indicated by A/C clicking off) while performing the following:
    • Shake, wiggle and bend WAC circuit between PCM and WAC relay.
    • Shake, wiggle and bend VPWR circuit to WAC relay.
    • Lightly tap on WAC relay to simulate road shock.

    If no faults are found, check for intermittent faults. Go to TEST Z, step  1). If any faults are found, isolate fault and repair as necessary. Perform PCM RESET PROCEDURE under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. Start engine and allow to idle. Turn A/C on and wait 15 seconds. Turn A/C off and repeat QUICK TEST to verify repair.

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