I was just comparing my list of service codes (for 1991 Aerostar, Bronco, Explorer, Ranger, E- and F- Series) to those in the FAQ and have noted the following discrepancies:

14 7.3L Diesel (c): Engine RPM Sensor circuit failure

16 (o): IDM signal not received.

18 2.3L (r): SPOUT circuit open
        (c): Erratic IDM input to processor
   4.0L (r): SAW circuit failure
        (c): Loss of IDM input to processor/IDM circuit failure
   All Others (r): SPOUT circuit open
              (c): Loss of IDM input to processor/SPOUT ckt grounded

23 7.3L Diesel (or): Fuel Injection Pump Lever (FIPL) circuit is out of self-
        test range.

26 2.9L/4.0L (or): MAF (Mass Air Flow) signal out of range. 
   All Others (or): Transmission Oil Temperature (TOT) sensor our of range.

28 (c): Loss of IDM - Right Side.

39 (c): AXOD lock-up failure

41 (c): no HEGO switching detected.

45 4.0L (c): Coil 1, 2 or 3 failure

47 (o): 4x4 switch is closed. (E40D)

48 (c): Loss of IDM - Left Side

49 (c): 1 - 2 shift error (E40D).

53 7.3L Diesel (oc): Fuel Injection Pump Lever (FIPL) circuit is greater than
        maximum voltage.

56 2.9L/4.0L (oc): MAF sensor voltage too high.
   All Others (oc): Transmission Oil Temperature (TOT) indicated -40F, circuit
        open (E40D)

57 (c): AXOD Neutral Pressure Switch (NPS) circuit failed open.

59 (c): 2 - 3 shift error (E40D).

62 (c): Converter Clutch error (E40D).

63 7.3L Diesel (oc): Fuel Injection Pump Lever (FIPL) circuit is below
        minimum voltage. 

65 (r): Overdrive Cancel Switch (OCS) not changing state (E40D).

66 2.9L/4.0L (oc): MAF circuit below minimum test voltage.
   All Others (oc): Transmission Oil Temperature (TOT) indicated 290F, circuit
        grounded (E40D).

67 (o): Neutral Drive Switch (NDS) open, AC left on. 
   2.9L/4.0L (c): Clutch switch circuit failure.
   All Others (c): Manual Lever Position (MLP) is out of range; A/C on (E40D)

69 (c): 3 - 4 shift error (E40D).

86 (o): Shift Solenoid (SS) circuit failure.

88 (o): Loss of dual plug input control.

89 (o): Converter Clutch Override (CCO) circuit failure.

91 (o): Shift Solenoid 1 (SS1) circuit failure (E40D)

92 (o): Shift Solenoid 2 (SS2) circuit failure (E40D)

93 (o): Coast Clutch Solenoid (CCS) circuit failure (E40D).

94 (o): Coast Clutch Control (CCC) solenoid circuit failure (E40D).

97 (o): Overdrive Cancel Light (OCIL).

98 (o): Electronic Pressure Control (EPC) driver open in ECA (E40D).

99 (oc): Electronic Pressure Control (EPC circuit failure (E40D).