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Diagnostic Aids

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Fig 1: Identifying WAC Circuits & Connector Terminals (Continental)
G00013304Courtesy of FORD MOTOR CO.
Fig 2: Identifying WAC Circuits & Connector Terminals (Cougar, Escape, Explorer, Explorer Sport, Explorer Sport Trac, Focus, Mountaineer, Ranger, Sable, Taurus, Town Car & Windstar)
G00013306Courtesy of FORD MOTOR CO.
Fig 3: Identifying ACPSW & ACCS Circuits & Connector Terminals (Cougar, Crown Victoria, Escape, Focus, Grand Marquis, Sable, Taurus & Town Car)
G00013307Courtesy of FORD MOTOR CO.
Fig 4: Identifying WAC Circuits & Connector Terminals (Crown Victoria, Econoline 4.2L, Excursion, Expedition, Grand Marquis, Navigator & Pickup)
G00013310Courtesy of FORD MOTOR CO.
Fig 5: Identifying ACCS Circuits & Connector Terminals (Econoline 4.2L, Excursion, Expedition, Navigator & Pickup)
G00013311Courtesy of FORD MOTOR CO.
Fig 6: Identifying ACCS Circuits & Connector Terminals (Econoline Except 4.2L)
G00013312Courtesy of FORD MOTOR CO.
Fig 7: Identifying ACPSW & ACCS Circuits & Connector Terminals (Explorer, Explorer Sport, Explorer Sport Trac, Mountaineer & Ranger)
G00013308Courtesy of FORD MOTOR CO.
Fig 8: Identifying WAC Circuits & Connector Terminal (LS)
G00013305Courtesy of FORD MOTOR CO.
Fig 9: Identifying ACCS Circuits & Connector Terminals (Windstar)
G00013309Courtesy of FORD MOTOR CO.
WIDE OPEN THROTTLE A/C CUTOFF RELAY LOCATIONS

Application Location
Crown Victoria & Grand Marquis In Relay Center, On Left Side Of Engine Compartment
LS In Auxiliary Junction Box, On Left Side Of Engine Compartment
All Others In Battery Junction Box, In Engine Compartment
    NOTE: 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 ON-DEMAND SELF-TEST.

  1. 1) KOEO & KOER DTC P1460: Verify ACCS PID Is Off
    This DTC indicates an excessive current draw 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:
    • A/C Or Defroster On During Self-Test
    • Open Or Shorted WAC Circuit
    • Faulty WAC Relay
    • Open VPWR Circuit To WAC Relay
    • Faulty PCM

    Ensure A/C and defroster were off during KOEO and/or KOER ON-DEMAND SELF-TEST. If A/C or defroster was on during self-test, turn system off and repeat self-test. If vehicle is equipped with A/C, start engine and allow to idle. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. If ACCS PID value indicates OFF, go to next step. If ACCS PID value indicates ON, ACCS input to PCM is requesting A/C, see 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 ground and WAC relay VPWR cavity (IGN RUN on Continental). See Fig 1, Fig 2, Fig 4 or Fig 8 . If voltage is more than 10.5 volts, go to next step. On LS, if voltage is 10.5 volts or less, go to TEST B, step 5) . On all other models, if voltage is 10.5 volts or less, repair open in VPWR (IGN RUN on Continental) circuit. See A/C wiring diagram in appropriate A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.
    3. NOTE: Different applications will use an ISO micro relay or mini relay for a WAC relay.

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

    1. 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 Fig 10.
      Fig 10: Identifying ISO Micro Relay Cavity Terminals
      G98B00332Courtesy of FORD MOTOR CO.

    2. 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 Fig 11.
      Fig 11: Identifying ISO Mini Relay Terminals
      G97D28186Courtesy of FORD MOTOR CO.

    On either relay, if resistance is as specified, go to next step. If relay resistance is not as specified, replace WAC relay.

  4. 4) Check WAC Circuit For Short To VPWR 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 ground and WAC ISO micro relay cavity No. 1, or WAC ISO mini relay cavity No. 85. See Fig 11 or Fig 10 . If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to VPWR 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 ground and WAC ISO micro relay cavity No. 1, or WAC ISO mini relay cavity No. 85. 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.

  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 No. 1 (ISO micro), or cavity No. 85 (ISO mini). See Fig 1, Fig 2, Fig 4 or Fig 8 . If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in WAC circuit.
    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: Steps  10) and  11) 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 - CNG & GASOLINE article.

  7. 10) ACCS PID OFF With A/C On: Check For VPWR To A/C Clutch
    Disconnect A/C clutch connector. Connect test light between A/C clutch harness connector terminals. Start engine. Turn A/C on. If test light illuminates, VPWR 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 VPWR not being supplied to A/C clutch. A/C clutch is not cause of low idle symptom. Return to SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V - CNG & GASOLINE article to diagnose low idle problem. Repair as necessary. If low idle is not a problem and A/C clutch does operate, 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 PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of ACCS circuit between PCM harness connector terminal No. 41 and A/C clutch harness connector. See Fig 6. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open circuit 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: DTC P1464 can be set if A/C or defroster were on during KOEO or KOER ON-DEMAND SELF-TEST.

  9. 19) KOEO & KOER DTC P1464: Check ACCS PID
    This DTC indicates 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)
    • Short To VPWR In ACCS Circuit
    • Faulty A/C Demand Switch
    • Faulty WAC Relay
    • Faulty PCM

    Ensure both A/C and defroster were off during KOEO ON-DEMAND SELF-TEST and KOER ON-DEMAND SELF-TEST. If either A/C or defroster were on during self-test, turn system off and repeat self-test. Turn ignition switch to ON position. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. On Econoline (except 4.2L), if ACCS PID value indicates ON, go to next step. On all others, if ACCS PID value indicates ON, ACCS input to PCM is requesting A/C. Go to appropriate A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING to diagnose A/C always ON symptom. 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: Check ACCS PID Value With A/C Cycling Switch Disconnected

    Turn ignition switch to OFF position. Disconnect A/C cycling clutch. Using scan tool, select ACCS PID from PID/DATA MONITOR & RECORD menu. If ACCS PID value 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 VPWR in A/C demand circuit to A/C cycling switch.

  11. 21) Check ACCS Circuit For Short To VPWR 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 ground and PCM harness connector terminal No. 41 (ACCS circuit). See Fig 6. If voltage is one volt or more, repair short to VPWR in ACCS circuit. Verify symptom is no longer present. If voltage is less than one volt, replace PCM.
    12. NOTE: 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 ON-DEMAND SELF-TEST.

  12. 30) Continuous Memory DTC P1460: Check WAC Circuit For Intermittent Short To Ground
    This DTC indicates an excessive current draw 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:
    • A/C Or Defroster On During Self-Test
    • Open Or Shorted WAC Circuit
    • Faulty WAC Relay
    • Open VPWR Circuit To WAC Relay
    • Faulty PCM

    Turn ignition and A/C switch on. 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 Fig 1, Fig 2, Fig 4 or Fig 8 .
    • Lightly tap on WAC relay to simulate road shock.

    If any faults are found, isolate fault and repair as necessary. If no faults are found, go to next step.

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

    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 VPWR (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 any faults are found, isolate fault and repair as necessary. Perform KEEP ALIVE RANDOM ACCESS MEMORY RESET PROCEDURE under CLEARING CODES. If no faults are found, fault cannot be duplicated at this time. Go to TEST Z, step  1).

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