skunk21

EEC-IV codes '86-'93

'86-'93 test plug location.




The OBD1 system in our cars can have trouble codes present w/o having the cel light on, this is common like I have stated many times.This is why the only reliable way to check the eec-iv system is to run a system self test.

The following failures or codes are the only ones that would trigger the CEL/MIL to turn on for the time the failure condition is present, once the failure is not present, the CEL will turn off:

CIRCUIT CODES
ACT 54, 64
ECT 51, 61
BP/MAP 22
MAF 26, 56, 66
TPS 23, 53, 63
EVP 31, 32, 34, 35
HEGO 41, 91, 42, 92

Intermittent codes will only trigger the CEL during the time the failure condition is present. Any other circuit failures may be present but not cause the cel to turn again and can only be identified by the self test.

Codes for '86 - '93

O= KOEO of code

CM= continuous memory code

R= engine runing code


11 - System Pass (O,CM,R)
12 - RPM Not Within Self Test Lower Limit (R), DC Motor Did Not Move (O,CM,R), Idle Speed Control motor or Air Bypass not controlling idle properly -generally idle too low
13 - RPM Not Within Self Test Upper Limit (R), Idle Speed Control motor or Air Bypass not controlling idle properly -generally idle too high
14 - Profile Ignition Pickup Circuit Failure (CM)
15 - Readout Memory Test Failed (O), Keep Alive Memory Test Failed (CM)
16 - RPM Too Low To Perform o2 Sensor Test (R)
17 - RPM below Self-Test limit with Idle Air Control off (R)
18 - Spark Out (SPOUT) Circuit Open (R), Loss Of Ignition Diagnostic Module Input To PCM/SPOUT Circuit Grounded (CM)
19 - Failure In PCM Internal Voltage (R), Erratic RPM During Hard Idle Self Test (R), Failure in EEC reference voltage (O)
21 - Engine Coolant Temperature (ECT) Sensor Out Of Self Test Range. 0.3 to 3.7 volts(O,R)
22 - Manifold Absolute Pressure/Barometric Pressure Sensor Out Of Self Test Range (O,CM,R)
23 - Throttle Position Sensor Out Of Self Test Range (O,CM,R)
24 - Intake Air Temperature/Air Charge Temperature Sensor Out Of Self Test Range. 0.3 to 3.7 volts(O,R)
25 - Knock Not Sensed During Dynamic Response Test (R)
26 - Mass Air Flow Sensor was greater than 0.7 volts with engine off (O), MAF sensor was not between 0.2 and 1.5 volts with engine running (R).
28 - Loss Of Ignition Diagnostic Module RH Side (CM)
29 - Insufficient Input From Vehicle Speed Sensor -To 1992 (CM), Insufficient Input From Programmable Speedometer/Odometer Module -From 1993 (CM)
31 - EGR Valve Position/Pressure Feedback EGR Circuit Below Minimum Voltage. 0.24 volts (O,CM,R)
32 - EGR Valve Position/Pressure Feedback EGR Voltage Below Closed Voltage. 0.24 volts (O,CM,R)
33 - EGR Valve Opening Not Detected (CM,R)
34 - EGR Valve Position/Pressure Feedback EGR Voltage Above Closed Limit (O,R), PFE or EVP circuit has intermittently failed above the closed limit of 0.67 volts (CM)
35 - EGR Valve Position/EGR Pressure Feedback EGR Circuit Above Maximum Voltage of 4.81 volts (O,R), PFE or EVP circuit has intermittently failed above the maximum limit of 4.81 volts (CM)
36 - System Indicates Lean At Idle (R)
37 - System Indicates Rich At Idle (R)
39 - AXOD converter bypass clutch not applying properly (CM)
41 - System Indicates Lean -passenger side(R), No o2 Sensor Switching Detected. always lean -passenger side(CM)
42 - System Indicates Rich -passenger side(R), No o2 Sensor Switching Detected. always rich -passenger side(CM)
43 - o2 Sensors indicate lean at Full Throttle (CM)
44 - Secondary Air System Inoperative. bank one, passenger side (R)
45 - Secondary Air Upstream During Self Test (R)
46 - Secondary Air Not Bypassed During Self Test (R)
47 - Measured Air Flow Low At Base Idle (R)
48 - Measured air flow too high at base idle (R)
49 - 1–2 Shift Error (CM)
51 - Engine Coolant Temperature Circuit Open (CM,O)
52 - Power Steering Pressure Switch Circuit Open (O), Power Steering Pressure Switch Circuit Did Not Change States (R)
53 - Throttle Position Sensor Circuit Above Maximum Voltage (CM,O)
54 - Intake Air Temperature/Air Charge Temperature Circuit Open (CM,O,R)
55 - Key Power Check (R)
56 - Mass Air Flow/Vane Air Flow Sensor Circuit Above Maximum Voltage (O,CM,R), MAF Sensor short to power (CM,R), Transmission Fluid Temperature Circuit Open (CM,O)
57 - AXOD Neutral pressure switch circuit failed open (CM)
58 - Idle Tracking Switch Circuit Open Or Grounded -CFI (O,R), Vane Air Temperature Sensor Input Greater Than Self Test Maximum -EFI (CM,O)
59 - 2–3 Shift Error (CM), AXOD 4/3 Pressure Switch Circuit Failed Closed (O), AXOD 4/3 Pressure Switch Circuit Failed Open (C)
61 - ECT Sensor Circuit Grounded (O,CM,R)
62 - Torque Converter Clutch Error (C,M), AXOD 4/3 Or 3/2 Pressure Switch Circuit Grounded (O)
63 - Throttle Position Sensor Circuit Below Minimum Voltage (O,CM,R)
64 - Intake Air Temperature/Air Charge Temperature Circuit Grounded (O,CM,R)
65 - Transmission Control Switch/Overdrive Cancel Switch Circuit Did Not Change States (R)
66 - , MAF signal below minimum test voltage of .4vdc (O,CM,R), Transmission Fluid Temperature Circuit Grounded (CM,O)
67 - Park Neutral Position Switch Circuit Open; A/C On -Manual (O), Manual Lever Position Sensor Out Of Range/A/C On (CM,O), Clutch Switch Circuit Failure (CM)
68 - Transmission recently overheated, or TOT sensor intermittently failed below 0.2 volts (CM)
69 - 3–4 Shift Error (CM)
71 - Software re-initialization detected or Cluster Control Assembly circuit failed (CM)
72 - Insufficient Manifold Absolute Pressure/Mass Air Flow Change During Dynamic Response Test (R)
73 - Insufficient Throttle Position Change During Dynamic Response Test (O,R)
74 - Brake On/Off Circuit Open–Not During Self Test (CM,R)
75 - Brake On/Off Circuit Closed/ECA Input Open (R)
76 - Insufficient Vane Air Flow Sensor Output Change During Dynamic Response Test (R)
77 - Operator Error Dynamic Response Test (R)
78 - Re-Initalization Check (R)
79 - A/C On/Defrost On During Self Test (O)
81 - Secondary Air Diverter Circuit Failure (O)
82 - Secondary Air Bypass Circuit Failure (O)
83 - EGR Control solenoid circuit failure (O)
84 - EGR Vacuum Regulator (EVR) Control Circuit Failure (O)
85 - CANP Circuit Failure (O)
86 - Adaptive fuel limit reached (CM), 3 – 4 Shift solenoid circuit failure (O)
87 - Primary Fuel Pump Circuit Failure (CM,O)
88 - Loss Of Dual Plug Input Control (CM), Throttle Kicker Fault (?)
89 - Converter clutch solenoid circuit failure (CM)
91 - o2 Sensor Circuit Indicates Lean -driver side(R), No o2 Sensor Switching Detected. always lean -driver side(CM), Shift Solenoid 1 Circuit Failure (O)
92 - o2 Sensor Circuit Indicates Rich -driver side(R), No o2 Sensor Switching Detected. always rich -driver side(CM), Shift Solenoid 2 Circuit Failure (O)
93 - Converter Clutch Solenoid Circuit Failure (O)
94 - Secondary Air Injection Inoperative. bank two, driver side (R), Torque Converter Clutch Solenoid Circuit Failure (O)
95 - Fuel Pump Circuit Open-PCM To Motor Ground (CM,O)
96 - Fuel Pump Circuit Open-Battery To PCM (CM,O)
97 - Transmission Control Indicator Lamp Circuit Failure (O)
98 - Hard Fault Present (R)
99 - Electronic Pressure Control Circuit Failure (CM,O)

Cylinder Balance Test Codes
10 - Cylinder #1 Failed Cylinder Balance Test
20 - Cylinder #2 Failed Cylinder Balance Test
30 - Cylinder #3 Failed Cylinder Balance Test
40 - Cylinder #4 Failed Cylinder Balance Test
50 - Cylinder #5 Failed Cylinder Balance Test
60 - Cylinder #6 Failed Cylinder Balance Test
70 - Cylinder #7 Failed Cylinder Balance Test
80 - Cylinder #8 Failed Cylinder Balance Test
90 - All cylinders passed Cylinder Balance Test