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                                             Engine Codes (Ford EEC-IV)

On the Fox body, the Ford harness to connect a code scanner can be found on the driver side, between the firewall
and strut tower in the engine bay.  The yellow arrow is pointing to the two necessary plugs that will be used.  If your
car hasn't been played with too much, they may still be under a small plastic housing attached to the rear side of the
strut tower.  Rigging up a volt meter is one way to get the codes without buying a scanner.  I've never tried that
method, but the scanner is only about $35 for these cars.  Spending the $35 on the scanner and book is much easier
than trying the other method, and then asking around what the information you found means.  It will also allow you
clear the codes when you've finished repairing the vehicle if necessary.

  •  11     System pass, no problems detected.

  •  12     Unable to raise engine speed above idle.  Check BYP valve.

  •  13     Unabe to lower engine speed below idle.  Check BYP valve.

  •  14     ECA detected an intermittent loss of the Profile Ignition Pick Up (PIP) signal.

  •  15     Problems with the Keep Alive Memory in the ECA.

  •  16     Idle speed control is beyond the self-test limit during Engine Run test.
               Check BYP, throttle adjustment, and vacuum leaks.  If any of the codes
               31-34 are also present, there may be an EGR problem creating code 16.

  •  17     RPM are below the self-test limit.  (Code 17 does not exist on the 2.3 or 5.0L).

  •  18     Loss of Tach signal to the ECA.

  •  19     Loss of power to the ECA during KOEO.  If the vehicle is equipped with DIS then it
               could be failure of CID identification or camshaft input signal.  Otherwise replace
               the ECA.

  •  21     Engine Coolant Temperature sender (ECT).  KOEO test is less than 50 deg or
                greater than 250 degrees Fahrenheit.

  •  22     No signal from the Manifold Absolute Pressure sensor (MAP) or Barometric
                Pressure sensor (BP).

  •  23     Throttle Position sensor (TP).  Voltage out of specification (outside the range of
                .2 to 4.84 volts).

  •  24     Air Charge Temperature (ACT).  Voltage out of specification (less than
               50 degrees or greater than 250).

  •  25     Knock Sensor (KS) signal not detected.

  •  26     Mass Air Flow sensor (MAF) out of range.  Output at idle should be between
               .2 and 1.5 volts.  KOER test the ECA expects to see about .8 volt from the MAF.

  •  27     Vehicle Speed Sensor (VSS) voltage too low.

  •  29     Vehicle Speed Sensor (VSS) did not deliver a signal to the ECA when other
                sensor show the vehicle is moving.

  •  31     EGR Valve Position sensor (EVP) voltage is below minimum specifications.

  •  32     EGR Valve Position sensor (EVP) voltage has gone beyond its limits.

  •  33     EGR Valve Position sensor indicates that the EGR valve is not opening.

  •  34     EGR Valve Position sensor signal voltage out of range.  Connection at the EVP
                sensor is bad, the sensor is faulty, or the EGR valve is not seating properly.

  •  35     EGR Valve Position (EVP) voltage is greater than 4.81 volts going to the ECA.

  •  38     Idle Tracking Switch (ITS) circuit open.  (Located in the ISC motor, the ITS
                tells the ECA when the throttle is closed.

  •  39     The Automatic Transaxle Overdrive (AXOD) bypass clutch is not applying

  •  41     EGO or HEGO sensor voltage was stuck low for the last 40 operations of the
                engine.  (Lean).

  •  42     EGO or HEGO sensor voltage was stuck high for too long.  (Rich).

  •  43     EGO indicates the engine is running lean at WOT, (only generated on the
                1.9L engine).

  •  44     Problems in the Thermactor Air Control system.  Check vacuum lines, air pump,
                diverter valve, and solenoids.

  •  45     Thermactor air flow is always upstream during the Engine Run self-test.  Check
                items listed in code 44.

  •  46     Thermactor Air System is unable to bypass air (vent to atmosphere).

  •  47     EGO sensor indicates Vane Airflow Meter (VAF) voltage too low.

  •  48     VAF voltage too high.  (Unique to the 1.9L engine).

  •  51     Engine Coolant Temperature (ECT) sensor voltage is too high (cold reading).

  •  52     Power Steering Pressure Switch circuit is open or no changes detected.

  •  53     Throttle Position (TP) sensor voltage is too high.

  •  54     Air Charge Temperature (ACT) sensor voltage is too high.

  •  55     Indicates that key power to the ECA pin 5 has been lost.  Check for a short.

  •  56     MAF sensor voltage is too high.

  •  57     Neutral Pressure Switch failed (AXOD transmission).

  •  59     Transmission code on all but the 3L SHO engine.  If on the SHO - check the
                low speed fuel pump circuit.

  •  61     ECT voltage is too low.

  •  62     Problem with the wiring between the ECA and the transmission.

  •  63     Throttle Position sensor voltage is too low.

  •  64     Air Charge Temperature sensor is too low.

  •  65     Transmission problem on all but the 1.9L engine.  Otherwise the ECA failed to
                enter closed-loop mode.  Check the EGO sensor wiring.

  •  66     MAF sensor voltage too low.

  •  67     Check voltage at pin 10 on the ECA.  (If greater than 1 volt, check for a short
                in the air conditioner clutch circuit.

  •  69     Refer to a transmission specialist.

  •  70     Problem with the ECA Data Communication Link

  •  71     Problem with the ECA - software reset was detected.

  •  72     Little vacuum change during the testing.  Check the vacuum supply to the
                MAP sensor.

  •  73     Throttle position did not change enough during the test.  Blip the throttle
                during a retest.

  •  74     Brake on/off (BOO) action was not detected during the test.

  •  75     Brake on/off switch always a closed circuit.  Check the voltage at ECA pin 2.

  •  77     Operator did not perform the goose test with the accelerator.

  •  78     Power interrupt detected.

  •  79     Air conditioner was possibly on during the test.

  •  81     Thermactor Air Diverter (TAD) solenoid failed.

  •  82     Thermactor Air Bypass (TAB) solenoid failed.

  •  84     EGR Vacuum solenoid failed.

  •  85     Cannister Purge (CANP) solenoid failed.

  •  87     Fuel pump relay circuit failed.  Check inertia switch first.

  •  88     Electric cooling fan failed.

  •  89     Refer to a transmission specialist.

  •  91     EGO sensor voltage on the left was stuck low for a period of time (Lean).

  •  92     EGO sensor voltage on the left was stuck high for a period of time (Rich).

  •  93     Throttle Position sensor voltage was too low at full ISC motor extension.

  •  94     Thermactor Air System with banks 5-8 are not working.

  •  95     Fuel pump secondary circuit failed or Thermactor air flow always upstream.

  •  96     Fuel pump secondary circuit failed or high-speed fuel pump circuit failed.
                Thermactor Air System will not bypass.

  •  97     Right side EGO sensor voltage indicates rich during lean conditions.

  •  98     A system problem is present causing the ECA to operate in a failsafe mode.
                Make repairs noted in a KOEO test prior to further testing.

  •  99     Repeat the KOEO test.  If the code returns, consider replacing the ECA.