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 -40°F 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 -40°F or circuit open (E4OD)
59 - 2-3 shift error (E4OD)
61 - ECT reads 254°F or circuit grounded
63 - TP circuit below minimum voltage
64 - ACT sensor grounded or input reads 254°F
65 - Overdrive cancel switch open, no change seen (E4OD)
66 - MAF sensor input below minimum voltage
66 - TOT grounded or reads 290°F (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 254°F
113 - ACT sensor circuit open or reads -40°F
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 254°F
118 - ECT sensor circuit open
118 - ECT sensor circuit below maximum voltage or reads -40°F
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



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  • These codes are pplicable only to some 1991 and up vehicles.

    Note: Some codes are for specific model cars only, so diregard anything about 1.9L cars...LOL

    Differences in test mode noted as:

    (O) =Key On Engine Off test
    (R) =Key On Engine Running test
    (M) =Memory code

    111 System checks OK

    112 (O,M) Intake Air Temperature (IAT) sensor is/was low or grounded -

    113 (O,M) IAT sensor is/was high or open -

    114 (O,R) IAT sensor out of range -

  • (O) = Key On Engine Off test
    (R) = Key On Engine Running test
    (M) = Memory code

    Note: Some codes may only be for certain model cars. So if you see something about 1.9L cars disregard it.

  • Types of Codes:

    See Eec Iv 2 Digit Codes
    See Eec Iv 3 Digit Codes

    NOTE: Some people have problems distinguishing the different codes. Read this section carefully. There are drawings of the code formats at the end of this section.

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    • A Phillips head screw driver
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  • Introduction: