EEC-IV Diagnostic Codes

11 - System pass 
12 - RPM unable to reach upper test limit 
13 - RPM unable to reach lower test limit 
14 - Pip circuit failure 
15 - PCM read only memory test failed 
15 - PCM keep alive memory test failed 
16 - IDM signal not received 
18 - SPOUT circuit open or spark angle word failure 
18 - IDM circuit failure or SPOUT circuit grounded 
21 - ECT out of self-test range 
22 - BP sensor out of self-test range 
22 - BP sensor or MAP out of range 
23 - TP sensor out of self-test range 
24 - ACT sensor out of self-test range 
25 - Knock not sensed during dynamic test 
26 - VAF/MAF out of self-test range 
26 - TOT out of self-test range 
26 - TOT sensor out of self-test range (E4OD) 
28 - Loss of IDM, right side 
29 - Insufficient input from vehicle speed sensor 
31 - PFE, EVP or EVR circuit below minimum voltage 
32 - EVP voltage below closed limit 
33 - EGR valve opening not detected 
34 - EVP voltage above closed limit 
35 - PFE or EVP circuit above closed limit 
41 - HEGO sensor circuit indicates system lean 
41 - No HEGO switching detected 
42 - HEGO sensor circuit indicates system rich 
44 - Thermactor air system inoperative-right side 
45 - Thermactor air upstream during self-test 
45 - Coil 1, 2 or 3 failure 
46 - Thermactor air not bypassed during self-test 
47 - 4WD switch closed (E4OD) 
48 - Loss of IDM, left side 
49 - 1-2 shift error (E4OD) 
51 - ECT/ACT reads -40F or circuit open 
52 - Power steering pressure switch circuit open 
52 - Power steering pressure switch always open or closed 
53 - TP circuit above maximum voltage 
54 - ACT sensor circuit open 
56 - VAF or MAF circuit above maximum voltage 
56 - TOT reads -40F or circuit open (E4OD) 
59 - 2-3 shift error (E4OD) 
61 - ECT reads 254F or circuit grounded 
63 - TP circuit below minimum voltage 
64 - ACT sensor grounded or input reads 254F 
65 - Overdrive cancel switch open, no change seen (E4OD) 
66 - MAF sensor input below minimum voltage 
66 - TOT grounded or reads 290F (E4OD) 
67 - Neutral/drive switch open or A/C on 
67 - Clutch switch circuit failure 
67 - MLP sensor out of range or A/C on (E4OD) 
69 - 3-4 shift error 
72 - Insufficient MAF/MAP change during dynamic test 
73 - Insufficient TP change during dynamic test 
74 - Brake on/off switch failure or not actuated 
77 - Operator error 
79 - A/C on during self-test 
79 - A/C or defrost on during self-test 
81 - Air management 2 circuit failure 
82 - Air management 1 circuit failure 
84 - EGR vacuum solenoid circuit failure 
85 - Canister purge solenoid circuit failure 
86 - Shift solenoid circuit failure 
87 - Fuel pump primary circuit failure 
88 - Loss of dual plug input control 
89 - Converter clutch solenoid circuit failure 
91 - Shift solenoid 1 circuit failure (E4OD) 
92 - Shift solenoid 2 circuit failure (E4OD) 
93 - Coast clutch solenoid circuit failure (E4OD) 
94 - Converter clutch solenoid circuit failure (E4OD) 
95 - Fuel pump secondary circuit failure - PCM to ground 
96 - Fuel pump secondary circuit failure - battery to PCM 
97 - Overdrive cancel indicator light - circuit failure (E4OD) 
98 - Electronic pressure control driver open in PCM (E4OD) 
98 - Hard fault present 
99 - Electronic pressure control circuit failure (E4OD) 
111 - System pass 
112 - ACT sensor circuit grounded or reads 254F 
113 - ACT sensor circuit open or reads -40F 
114 - ACT outside test limits during KOEO or KOER tests 
116 - ECT outside test limits during KOEO or KOER tests 
117 - ECT sensor circuit grounded 
117 - ECT sensor circuit below minimum voltage or reads 254F 
118 - ECT sensor circuit open 
118 - ECT sensor circuit below maximum voltage or reads -40F 
121 - Closed throttle voltage higher or tower than expected 
122 - TP sensor circuit below minimum voltage 
123 - TP sensor circuit below maximum voltage 
126 - BP or MAP sensor higher or lower than expected 
128 - MAP vacuum circuit failure 
129 - Insufficient MAF or MAP change during dynamic responded test 
144 - No HEGO switching detected 
167 - Insufficient TP change during dynamic response test 
171 - Fuel system at adaptive limit, HEGO unable to switch 
172 - HEGO shows system always lean 
173 - HEGO shows system always rich 
174 - HEGO switching time is slow 
179 - Fuel at lean adaptive limit at part throttle; system rich 
181 - Fuel at rich adaptive limit at part throttle; system lean 
182 - Fuel at lean adaptive limit at idle; system rich 
183 - Fuel at rich adaptive limit at idle; system lean 
211 - PIP circuit fault 
212 - Loss of IDM input to PCM or SPOUT circuit grounded 
213 - Spout circuit open 
224 - Erratic IDM input to processor 
225 - Knocked not sensed during dynamic response test 
311 - Thermactor air system inoperative 
312 - Thermactor air upstream during self-test 
313 - Thermactor air not bypassed during self-test 
327 - EVP or DPFE circuit below minimum voltage 
328 - EGR closed voltage higher than expected 
332 - Insufficient EGR flow detected 
334 - EGR closed voltage higher than expected 
337 - EVP or DPFE circuit above maximum voltage 
411 - Cannot control rpm during KOER low rpm check 
412 - Cannot control rpm during KOER high rpm check 
452 - Insufficient input from vehicle speed sensor 
511 - EEC processor ROM test failed 
512 - EEC processor Keep Alive Memory test failed 
513 - Failure in EEC processor internal voltage 
519 - Power steering pressure switch circuit open 
521 - Power steering pressure switch did not change state 
525 - Vehicle in gear or A/C on during self-test 
536 - Brake on/off circuit failure, switch not actuated during KOER test 
538 - Insufficient RPM change during KOER dynamic response test 
538 - Operator error 
542 - Fuel pump secondary circuit failure: PCM to ground 
543 - Fuel pump secondary circuit failure: Battery to PCM 
552 - Air management 1 circuit failure 
553 - Air management 2 circuit failure 
556 - Fuel pump primary circuit failure 
558 - EGR vacuum regulator circuit failure 
565 - Canister purge circuit failure 
569 - Canister purge 2 circuit failure 
617 - 1-2 shift error (E4OD) 
618 - 2-3 shift error (E4OD) 
619 - 3-4 shift error (E4OD) 
621 - Shift solenoid 1 circuit failure 
622 - Shift solenoid 2 circuit failure 
624 - EPC solenoid or driver circuit failure 
625 - EPC driver open in PCM 
626 - Coast clutch solenoid circuit failure (E4OD) 
627 - Converter clutch solenoid circuit failure (E4OD) 
628 - Converter clutch error (E4OD) 
629 - Converter clutch control circuit failure 
631 - Overdrive cancel indicator light circuit failure 
632 - Overdrive cancel switch not changing states (E4OD) 
633 - 4WD switch is closed 
634 - MLP sensor voltage out of self-test range, A/C on 
636 - TOT sensor voltage out of self-test range 
637 - TOT sensor circuit above maximum voltage 
638 - TOT sensor circuit below minimum voltage 
654 - MLP sensor not in park position 
998 - Hard fault present 

Definitions: 

ACT   = Air Charge Temperature Sensor 
BP    = See MAP 
EEC   = Electronic Engine Control System 
ECT   = Engine Coolant Temperature Sensor 
EGR   = Exhaust Gas Recirculation Valve 
EVP   = EGR Valve Position Sensor 
HEGO  = Heated Exhaust Gas Oxygen Sensor 
KOEO  = Key On Engine Off 
KOER  = Key On Engine Running 
MAF   = Mass Air Flow Sensor 
MAP   = Manifold Absolute Pressure Sensor 
MLP   = Manual Lever Position 
PCM   = Powertrain Control Module 
SPOUT = Distributor Jumper to Allow Initial Timing 
TP    = Throttle Position Sensor 

Comments 

   1.Not all codes apply to all vehicles 
   2.Some codes have 2 listings, use the appropriate one 

This info was found at Chilton's "FORD Full Size Trucks 1987-96 Repair Manual"


Here's another chart we found with some slight differences...

EEC-IV Diagnostic Codes, Rev. 1.1 2/25/93 

11 (orc): No problems found in this portion of the test

12 (r): ECA could not increase idle speed above normal idle. 
Suspect throttle body coking. KE1

13 (r): ECA could not lower idle speed. 
Suspect Idle Bypass valve problems. KE15

14 (c): Intermittent PIP signal operation. 
Suspect PIP sensor or TFI module, or grounding or
interference problems at the TFI module. Y1

15 (o): ECA ROM test failure- failure is internal to ECA. 
(c) ECA KAM (Keep Alive RAM Memory) failure. Q10

18 (r*): Loss of TACH signal from TFI (Thick Film Integration- the module 
on the side of the distributor) module to the ECA. There is an open in the SPOUT circuit. 
Suspect SPOUT connector. N1

19 (o): Failure of ECA voltage regulator. Replace ECA.

21 (or): ECT (Engine Coolant Temp) out of range. Coolant is less than 50degF 
for KOEO, or less than 180degF for KOER, or greater than 250degF for either. 
If coolant temp is in proper range, suspect ECT sensor (It won't be, for KOER 
tests on cars tha have a 160degF thermostat!) DE1, DE90

22 (orc*): MAP (Manifold Absolute Pressure, for speed-density cars) or 
BP (Barometric Pressure, for mass-air cars) sensor signal out of range. 
Suspect MAP or BP sensor and harness. DF1, DF90

23 (or): Closed throttle TP (Throttle Position) sensor voltage out of range. 
Suspect TP sensor. DH1

24 (or): ACT (Air Charge Temperature) sensor voltage out of range. 
Suspect ACT sensor and harness. 1984-85 2.3 Turbo - Vane Air Flow voltage 
out of range. DA1

25 (r): 2.3 Turbo. Knock Sensor failure. DG1

26 (or): VAF (Vane Air Flow, 2.3L Turbo) or MAF (Mass Air Flow) signal out of 
range. Suspect sensor and harness. DK1

28 (or): 1986+ 2.3 Turbo. Vane Air Temperature out of range.

34 (r): 2.3 Turbo. EGR On/Off not working. KA1

41 (c): 2.3 Turbo. EGO read lean for more than 15 seconds while in closed loop. HA11

42 (c): 2.3 Turbo. EGO read rich for more than 15 seconds while in closed loop. HA8

51 (orc*): ECT voltage too high (coolant too cold, circa -40degF!). 
Suspect ECT, harness. DE10, DE91

53 (orc*): TP sensor voltage too high (indicates WOT condition). DH3, DH90

54 (orc*): ACT (air Charge Temperature) sensor voltage too high. DA10, DA90

56 (orc*): MAF (VAF for 2.3 Turbo) sensor voltage too high. DK10, DK90

61 (orc*): ECT voltage too low- indicates coolant temp greater than 250degF. DE20, DE94

63 (orc*): TP sensor voltage too low. DH10, DH94

64 (orc*): ACT (1984-84 2.3 Turbo, VAT) sensor voltage too low, indicates intake 
air temp greater than 250degF. DA20, DA93

66 (rc*): MAF (2.3 Turbo, VAF) below minimum test voltage. DK20, DK93

67 (o): Clutch switch open, AC left on, transmission in gear. FA1

68 (oc): 1986+ 2.3 Turbo. VAT out of range.

73 (r): Insufficient goose during Dynamic Response test. Rerun test, goose it 
harder. 2.3 Turbo - Faulty Throttle Position sensor. DH20

74 No Brake Switch Actuation / Cruise Control Switch Actuation Detected

76 (r): 2.3L Turbo only. Insufficient VAF variation seen during Dynamic 
Response test. DK30

77 (r): No goose detected durning Dynamic Respose test. Rerun test, goose it 
harder. M1 81 (o): 2.3 Turbo. Boost control circuit failure. KN1 

82 (o): 2.3 Turbo. Check EDF signal to Integrated Controller for short to ground.

83 (o): 2.3L Turbo only. Check for EDF signal to Integrated Controller for open circuit.

84 (o): EVR solenoid circuit failure. 2.3 Turbo - Check for EGR solenoid open circuit.

85 (o): 2.3 Turbo with Automatic (T-Bird). Check for 3-4 shift solenoid open circuit.

87 (oc): FP relay circuit failure- suspect intertia switch, fusible link, FP relay. J1

98 (r): Hard fault present. The ECA is running in FMEM (Failure Effects Management Mode), 
so something is royally screwed up that the KOEO test should have told you about. 
Rerun KOEO and fix whatever you find there.

99: ECA hasn't learned yet

This info was found at:http://www.corral.net/20anngt/


To return to the Main Page click here