Diagnostic Aids

Perform this test only when directed here by QUICK TEST or a driveability symptom. This test is only intended to diagnose:

Wiring harness circuits (EDF, HEDF, EDF POWER-TO-FAN, HEDF POWER-TO-FAN, IGN START/RUN and GND).
EDF and HEDF relays.
Cooling fan.
ECA.

ECA determines engine cooling fan requirements and controls fan operation through EDF and HEDF outputs. HEDF relay is normally open. EDF is normally closed for Escort and Tracer and open for Probe.

Fig 1: EDF/HEDF Circuit ID

Fig 2: EDF/HEDF Circuit Connector Terminal ID

1) Code 563 Or Code 564: Check For Voltage At EDF/HEDF Relay Code 563 indicates faulty HEDF primary circuit. Code 564 indicates faulty EDF primary circuit. Possible causes for these faults are:

Open or shorted circuit.
Faulty fan relay.
Faulty ECA.

Turn ignition off. Disconnect EDF and HEDF relays. Disconnect cruise control servo. Set Digital Volt-Ohmmeter (DVOM) on 20-volt scale. Turn ignition on. Measure voltage between IGNITION START/RUN circuit at EDF/HEDF relay wiring harness connector and chassis ground. If voltage is more than 10.5 volts, go to step 2). If voltage is 10.5 volts or less, check fuse. If fuse is okay, repair open circuit and repeat QUICK TEST .

2) Enter Output State Check Use only VOM or DVOM for this step. DO NOT use scan tester. Turn ignition off. Disconnect cruise control servo wiring harness connector. Connect DVOM negative lead to STO terminal at self-test connector. Connect positive lead to positive battery terminal. Install a jumper wire between STI terminal and SIG RTN terminal at Self-Test connector. See Figure -Figure in CIRCUIT TEST B. Perform KOEO SELF-TEST until continuous memory test is complete. DVOM will read less than 1.0 volt when test is complete to indicate ECA has entered OUTPUT STATE CHECK. Depress and release throttle. If voltage increases to more than 10.5 volts, stay in OUTPUT STATE CHECK and go to step 3). If voltage does not increase to at least 10.5 volts, depress throttle to wide open throttle and release. If STO voltage increases to specification, leave equipment connected and go to CIRCUIT TEST QC step 2).

3) Check For EDF/HEDF Circuit Cycling With vehicle still in OUTPUT STATE CHECK, disconnect EDF or HEDF relay. Connect DVOM positive lead to IGNITION START/RUN circuit. Connect negative test lead to EDF or HEDF terminal at relay wiring harness connector. Depress throttle to cycle outputs off. Observe DVOM and depress throttle again. For EDF, wait until CHECK ENGINE light flashes once (about 10 seconds). For HEDF, wait until CHECK ENGINE light flashes twice (about 15 seconds). Release throttle. EDF/HEDF output is now on. To cycle off output, depress and release throttle. If voltage cycles (about a 1-volt change), replace EDF or HEDF relay and repeat QUICK TEST . If voltage does not cycle, remove jumper and go to step 4).

4) Check Continuity of EDF/HEDF Circuit Turn ignition off. Disconnect EDF or HEDF relay. Disconnect 60-pin ECA connector. Inspect terminals, and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving ECA disconnected. Set DVOM on 200-ohm scale. Perform appropriate following check:

Code 563 Measure resistance between breakout box HEDF test pin and HEDF terminal at HEDF relay wiring harness connector.
Code 564 Measure resistance between breakout box EDF test pin and EDF terminal at EDF relay wiring harness connector.

If resistance is less than 5 ohms, go to step 5). If resistance is 5 ohms or more, repair open circuit. Reconnect all components, and repeat QUICK TEST.

5) Check EDF/HEDF Circuit For Short To Power Disconnect EDF or HEDF relay. Turn ignition on. Measure voltage between breakout box EDF or HEDF test pin and negative battery terminal. If voltage is less than 1.0 volt, go to step 6). If voltage is 1.0 volt or more, repair short circuit. Reconnect all components, and repeat QUICK TEST . If code is still present, replace ECA.

6) Check EDF/HEDF Circuit For Short To Ground Turn ignition off. Disconnect EDF or HEDF relay. Measure resistance between breakout box EDF or HEDF test pin and test pins No. 40 and 60. If resistance is more than 10,000 ohms, replace ECA. Reconnect all components, and repeat QUICK TEST . If resistance is 10,000 ohms or less, repair short circuit. Reconnect all components, and repeat QUICK TEST.

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.

10) Low-Speed (EDF) And/Or High-Speed (HEDF) Cooling Fan Does Not Operate Turn ignition off. Disconnect EDF relay. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between HEDF relay terminal at EDF relay wiring harness connector and negative battery terminal. See Fig 3 . If voltage is more than 10.5 volts, go to step 13). If voltage is 10.5 volts or less, go to step 11).

Fig 3: EDF Relay Vehicle Harness Connector

11) Check For Voltage To HEDF Relay Turn ignition off. Disconnect EDF and HEDF relays. Set DVOM on 20-volt scale. Turn ignition on. Measure voltage between IGNITION RELAY (BATT + for Probe) terminal at HEDF relay vehicle harness connector and negative battery terminal. See Fig 4 . If voltage is more than 10.5 volts, go to step 12). If voltage is 10.5 volts or less, check fuse and ignition relay (Escort and Tracer). If fuse and/or relay are okay, repair open circuit.

Fig 4: HEDF Relay Vehicle Harness Connector

12) Check Continuity Between EDF & HEDF Relays Turn ignition off. Disconnect EDF and HEDF relays. Measure resistance between HEDF terminal at EDF relay vehicle harness connector and output to EDF terminal at HEDF relay vehicle harness connector. See Fig 5 . If resistance is less than 5 ohms, replace HEDF relay. If resistance is 5 ohms or more, repair open circuit and reconnect all components.

Fig 5: EDF & HEDF Relay Harness Connectors

13) Check Circuits From EDF Relay To Fan Turn ignition off. Disconnect EDF relay. Install a jumper wire between HEDF terminal and POWER-TO-FAN terminal at EDF relay vehicle harness connector. See Fig 6 . Turn ignition on. If fan operates, remove jumper and go to step 16). If fan does not operate, remove jumper wire and go to step 14).

Fig 6: EDF Relay Vehicle Harness Connector

14) Check EDF POWER-TO-FAN Circuit Continuity Turn ignition off. Disconnect EDF relay and cooling fan. Measure resistance between POWER-TO-FAN terminal at EDF vehicle harness connector and POWER-TO-FAN input terminal at cooling fan vehicle harness connector. See Fig 7 . If resistance is 5 ohms or less, go to step 15). If resistance is more than 5 ohms, repair open circuit and reconnect all components.

Fig 7: EDF & Cooling Fan Vehicle Harness Connector (Escort & Tracer)

15) Check Cooling Fan Ground Circuit Turn ignition off. Disconnect EDF relay and cooling fan. Measure resistance between GND circuit at cooling fan vehicle harness connector and negative battery terminal. If resistance is less than 5 ohms, replace cooling fan. Reconnect all components. If resistance is 5 ohms or more, repair open circuit.

16) Check Circuits From HEDF Relay To Fan Turn ignition off. Disconnect EDF relay. Disconnect 60-pin ECA connector. Inspect terminals. Repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV), leaving ECA disconnected. On Escort and Tracer, install a jumper wire between test pins No. 31 and 40 at breakout box. On Probe, install a jumper wire between test pins No. 33 and 40 at breakout box. Turn ignition on. If fan runs at high speed, replace EDF relay. If fan does not run at high speed, remove jumper wire and go to step 17).

17) Check HEDF Power-To-Fan Voltage At Fan Turn ignition off.Disconnect EDF relay and cooling fan. On Escort and Tracer, install a jumper wire between test pins No. 31 and 40 at breakout box. On Probe, install a jumper wire between test pins No. 33 and 40 at breakout box. Turn ignition on. Measure voltage between HEDF POWER-TO-FAN circuit at cooling fan vehicle harness connector and negative battery terminal. See Fig 8 . If voltage is more than 10.5 volts, replace cooling fan. If voltage is 10.5 volts or less, remove jumper wire and go to step 18).

Fig 8: Cooling Fan Vehicle Harness Connector (Escort & Tracer)

18) Check HEDF POWER-TO-FAN Circuit Continuity Turn ignition off. Disconnect cooling fan, HEDF and EDF relays. Measure resistance between HEDF POWER-TO-FAN terminal at HEDF relay vehicle harness connector and HEDF POWER-TO-FAN terminal at cooling fan vehicle harness connector. See Fig 9 . If resistance is 5 ohms or less, replace HEDF relay. If resistance is more than 5 ohms, repair open circuit. Reconnect all components, and recheck system operation.

Fig 9: HEDF Relay Vehicle Harness Connector (Escort & Tracer)

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 18) to step 25). No test procedures have been omitted.

25) Low-Speed (EDF) or High-Speed (HEDF) Cooling Fan Always On Ensure A/C is off. For Probe models, go to step 26). On Escort and Tracer, ensure relay contacts are not always closed if cooling fan is always on with ignition off but operates normally with ignition on. If relay is okay, check circuit to fan relays for a short to power. If system does not operate as described, go to step 26).

26) Check For Relay Always Closed Turn ignition off. Disconnect EDF relay. Turn ignition on. If fan continues to run, go to step 27). If fan does not continue to run, replace EDF relay.

27) Check HEDF Relay Turn ignition off. Disconnect EDF and HEDF relays. Turn ignition on. If fan continues to run, go to step 28). If fan does not continue to run, replace HEDF relay.

28) Check EDF POWER-TO-FAN Circuit For Short to Power Turn ignition off. Disconnect EDF and HEDF relays. Disconnect cooling fan. Turn ignition on. Measure voltage between EDF POWER-TO-FAN circuit at cooling fan vehicle harness connector and negative battery terminal. See Fig 10 . If voltage is 1.0 volt or more, repair short to power in EDF POWER-TO-FAN circuit. If voltage is less than 1.0 volt, repair short to power in HEDF POWER-TO-FAN circuit.

Fig 10: Cooling Fan Vehicle Harness Connector (Escort & Tracer)