1990 35th Anniversary Thunderbird Registry

EEC-IV System Fault Codes

Vehicle Test Performed:
O = Key on Engine Off (KOEO)
R = Key on Engine Running(KOER)
C = Continuous Memory

EEC IV Code Test Performed Code Definition
11   System Pass
12 R RPM at idle out of range / high
13 O,R,C RPM at idle out of range / low
14 O,C Profile Ignition Pickup (PIP) failure
15 O PCM Read Only Memory (ROM) test failed
15 C Power interruption to computer memory or PCM Keep Alive Memory (KAM) test failed
18 R,C SPOUT circuit open or IDM circuit failure (SPOUT circuit grounded
18 C Loss of TACH input to ECA/ SPOUT circuit grounded
19 C Distributorless Ignition Cylinder Identification circuit failure
21 O,R,C Cooling temperature sensor out of specified range or ECT out of range
22 O,R,C Manifold Absolute Pressure (MAP) or BARO sensor out of range
23 O,R,C Throttle Position (TP) sensor signal out of range
24 O,R Intake Air Charge Temperature sensor or vane air temperature sensor or EDIS fault
25 R Knock Sensor not sensed during Dynamic Response Test
26 O,R Mass air flow sensor out of range
29 C Insufficient input from Vehicle Speed Sensor
31 O,R,C EGR valve position sensor below minimum voltage
32 O,R,C EGR valve not seated. Closed voltage low.
33 R,C EGR valve not opening. Insufficient flow.
34 O,R,C EGR valve pressure transducer voltage above closed limit
35 O,R,C EGR signal voltage too high
38 C Idle control circuit open
39 C Automatic overdrive circuit failure (transmission failure)
41 R,C Oxygen Sensor indicating system lean, right side
42 R,C Oxygen Sensor indicating system rich, right side
44 C Exhaust Gas Temperature Switch failed; catalyst too high temperature
45 C Coil Pack 1 (A) circuit failed
46 C Coil Pack 2 (B) circuit failed
47 C Spark Location Error
48 C Coil Pack 3 (C) ciruit failed
49 C SPOUT signal default to 10 degrees BTDC
51 O,C Coolant temperature sensor circuit open
52 O,R Power Steering Pressure Switch (PSPS) circuit open
53 O,C Throttle Position (TP) sensor above maximum voltage
54 O,C Air Charge Temperature sensor circuit open
61 O,C Engine coolant temperature sensor circuit grounded
63 O,C Throttle Position (TP) circuit fault, below minimum voltage
64 O,C Air Charge Temperature circuit grounded
66 C Mass air flow sensor fault, below minimum voltage
67 O,R,C Neutral Drive Switch fault, switch circuit open / Air conditioner on during self-test
67 C Clutch switch fault
72 R Insufficient Mass Air Flow change during Dynamic Response Test
73 R Insufficient Throttle Position (TP) sensor output during Dynamic Response Test
74 R Brake On/Off (BOO) switch fault
75 R Brake On/Off (BOO) switch fault
77 R Wide Open Throttle not sensed during Dynamic Response Test
79 O Air Conditioner "ON" during self-test / defrost on
82 O Supercharger By-pass Solenoid circuit failure
83 O EGR control circuit fault (3L CFI, 2.3L EFI, ex. turbo)
83 O High Speed Fan circuit failure
84 O,R EGR Vacuum Regulator circuit failure
85 O,R Canister Purge circuit failure
87 O,R,C Fuel pump primary circuit fault
88 O Electro Drive FAn circuit failure
91 R,C Oxygen sensor indicating system lean, left side
92 R,C Oxygen sensor indicating system rich, left side
95 O,C Fuel pump circuit open, ECA to motor
96 O,C Fuel pump circuit open, Battery to ECA
98 R Computer detected hard fault (EEC in FMEM or Failure Management Effects Mode)
Note: Code 98 puts the Engine Control Assembly computer into what some call the "limp home" mode. Default sensor values are used for the EEC system to attempt to keep the vehicle operating until it can be taken to a mechanic. This mode occurs when a major component or computer failure has occurred and the computer needs values to operate the vehicle well enough to drive.