The EEC-IV equipped engines use an older diagnostic system to monitor and report engine related malfunctions.  This system is known as On Board Diagnostics (OBD-I).  The Diagnostic Trouble Codes (DTC’s) are two or three digit numbers and can be read through the use of a scan tool, an analog voltmeter, or with the Malfunction Indicator Light (MIL) [Check Engine or Service Engine Soon light].

Steps on how to test the EEC-IV / OBD-I vehicles can be found here at: Testing EEC-IV Equipped Engines

This page contains the 2-digits codes that you will get as a result of that test.

Differences in test mode noted as:

(O) = Key On Engine Off test

(R) = Key On Engine Running test

(M) = Memory code

Code

Definition
11 System checks OK
12 Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too low) – ISC
13 (O) ISC did not respond properly (extends to touch throttle then retracts for KOEO) – ISC
(R) Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too high)
(M) ISC sticking, open ITS circuit or TP sticking
14 Ignition pickup was erratic – Ignition Systems
E4OD Transmission diesel RPM sensor – Diesel RPM sensor
15 (O) No Keep Alive Memory power to PCM pin 1 or bad PCM (Memory Test Failure)
(M) KAM (pin 1) was interrupted (was battery disconnected ?)
16 1.9L & 2.5L – Throttle stop set too high – IDLE or Idle Set Procedures
2.3L – RPM’s too low – IDLE
(O) Electronic ignition – IDM circuit fault – Ignition Systems
17 1.9L & 2.5L – Throttle stop set too low – IDLE
18 (R) Check base timing & advance function – Timing Tests
(M) Ignition TACH signal erratic – Ignition Systems
19 (O) No Vehicle Power (pins 37 + 57) or bad PCM VPWR Diagnosis
(R) Erratic idle during test (reset throttle & retest) – Idle Set Procedures
Electronic ignition Cylinder ID sensor/circuit problem – Ignition Systems
21 Engine Coolant Temperature (ECT) sensor out of range – ECT
22  MAP (vacuum) or BARO signal out of range – MAP
23 Throttle sensor out of range or throttle set too high – TPS
24  Intake Air Temperature (IAT) or Vane Air Temperature (VAT) sensor out of range – IAT VAT
25 Knock sensor not tested (ignore if not pinging) – KS
26 Mass Air Flow (MAF) or Vane Air Flow (VAF) out of range – MAF VAF
Transmission Oil Temperature (TOT) sensor out of range – Transmissions
27 Vehicle Speed Sensor problem – VSS
28 Vane Air Temperature (VAT) sensor out of range – VAT
2.3L w/Electronic Ignition – Cyl ID, IDM low or right coil pack failure – Ignition Systems
29 Vehicle Speed Sensor problem – VSS
EGR CODES DEPEND ON WHAT SYSTEM TYPE THE VEHICLE IS EQUIPPED WITH:
EVP is for vehicles equipped with EGR solenoid(s), with or without an EVP sensor
EVR is for vehicles equipped with an EGR Vacuum Regulator (EVR) and an EGR Valve Position (EVP) sensor
PFE is for vehicles with Pressure Feedback EGR (PFE) sensor and and an EGR Vacuum Regulator (EVR)
If you don’t know what type of system you have, go to the EVP heading, which is the first one.
There are pictures under the different headings to help you identify the system.
31 EVP – (O, R, M) EVP signal is/was out of range – EVP
EVR – (O, R, M) EVP signal is/was low – EVR
PFE – (O, R, M) PFE signal is/was low – PFE
32 EVP – (R) EGR not responding properly during test – EVP
EVR – (O, R, M) EVP signal is/was low – EVR
PFE – (R, M) PFE shows low pressure, EGR not seating or memory, not seating intermittently – PFE
33 ALL – (O, M) EGR did not open/ respond during test or if memory code, did not open intermittently – EVP EVR PFE
34 EVP – (R) EGR did not respond properly during test – EVP
EVR – (O, R, M) EVP sensor is/was high – EVR
PFE – (O, R, M) PFE sensor is/was out of range – PFE
35 EVP – (R) Engine RPM’s too low to test EGR system – EVP
EVR – (O, R, M) EVP sensor signal is/was high – EVR
PFE – (O, R, M) PFE sensor signal is/was high – PFE
38 Idle Tracking Switch signal was intermittent – ISC
39 Transmission Torque Converter clutch not engaging – Transmissions
40  SERIES FUEL/AIR INJECTION CODES ON VEHICLES WITH DUAL OXYGEN SENSORS REFER TO THE RIGHT OR REAR SENSOR. EXCEPT: 1984-1988 3.8L ENGINES: LEFT SENSOR
41 (R) System lean – Fuel control
(M) System was lean for 15 seconds or more (no HO2S switching) – Fuel control
42 (R) System rich – Fuel control
(M) System was rich for 15 seconds or more (no HO2S switching) – Fuel control
43   (R) HO2S sensor not reading (run at 2000 rpm’s for 2 minutes and retest – check for HO2S switching)
(M) Was lean at WOT for 3 seconds or more – Fuel control
44 AIR system inoperative – Air Injection
45 AIR not Diverting (AIRD) – Air Injection
Electronic Ignition – coil primary circuit failure – Ignition Systems
46 AIR Bypass (AIRB) not working – Air Injection
Electronic Ignition – primary circuit failure coil 2 – Ignition Systems
47 Low flow unmetered air (check for small vacuum leaks, injector o’rings, gaskets etc.)
E4OD transmission 4×4 switch/circuit problem – Transmissions
48 High flow unmetered air (check for large vacuum leak, inlet hoses etc.)
Electronic Ignition – coil primary circuit failure – Ignition Systems
49 Electronic Ignition – spout signal circuit problem – Ignition Systems
Transmission 1/2 shift problem – Transmissions
51 Engine Coolant Temperature (ECT) sensor signal is/was too high – ECT
52 Power Steering Pressure Switch/circuit open – PSP
(R) Did you turn wheel during test ?
53 Throttle Position sensor too high – TPS
54 Intake Air Temperature (IAT) or Vane Air Temperature (VAT) signal high – IAT VAT
55 No or low (under 7.5 V) Key Power to PCM pin 5
56 Vane Air Flow (VAF) or Mass Air Flow (MAF) sensor high – VAF MAF
Transmission Oil Temperature sensor too high – Transmissions
57 Intermittent in Park/Neutral/ Switch or Neutral Pressure switch circuit – PNP or Transmissions
1990 Scorpio – Octane jumper installed (information only code – to inform you if it is installed or not)
58 Idle Tracking Switch (ITS) signal problem ISC
Vane Air Temperature (VAT) sensor out of range or open – VAT
59 AXOD 4/3 circuit fault – Transmissions
3.0L SHO – Low speed fuel pump circuit problem – Power / Fuel Pump Circuits
Transmission 2/3 shift problem – Transmissions
1990 Scorpio – Idle jumper installed (information only code – to inform you if it is installed or not)
61 Engine Coolant Temperature (ECT) sensor is or was too low – ECT
62 AXOD (KOEO only) 3/2 circuit short to ground – Transmissions
AXOD (KOEO AND KOER) 4/3 circuit failure – Transmissions
E4OD excessive converter clutch slippage – Transmissions
63 Throttle Position Sensor (TPS) signal too low TPS
64 Intake Air Temperature (IAT) or Vane Air Temperature (VAT) signal low or grounded – IAT VAT
65 Check intermittent HO2S (signal or ground) – Fuel Control
(R) E4OD truck – cycle OD cancel switch after engine ID is received – Transmissions
1984 3.8L ONLY – O, M Battery voltage high (check for electrical system overcharging)
66 Vane Air Flow (VAF) or Mass Air Flow (MAF) signal low – VAF MAF
Transmission Oil Temperature (TOT) signal low (possibly grounded) – Transmissions
67 Park/Neutral circuit fault – PNP
Transmission Manual Lever Position (MLP) sensor circuit – Transmissions
(M) Intermittent Park Neutral Position (PNP) sensor fault – PNP
68 Idle Tracking Switch (ITS) circuit (possibly grounded) – ISC
Vane Air Temperature (VAT) sensor out of range or grounded – VAT
3.8L AXOD -Transmission Temperature Switch (TTS) open – Transmissions
Electronic Transmission – Transmission Oil Temperature (TOT) sensor was overheated – Transmissions
69 AXOD transmission (O) 3/2 switch closed (possible short circuit) – Transmissions
AXOD (M) 3/2 switch open (poss short to power) – Transmissions
E4OD 3/4 shift problem – Transmissions
70 (M) 3.8L AXOD – Data link to instrument cluster fault. Service any other EEC codes, erase memory and retest.
If code is still present refer to instrument cluster diagnosis manual.
71 (M) 1.9L TBI, 2.3L TBI, 2.5L TBI – ITS signal was grounded when throttle should have been opening ITS – ISC
ISC motor problem or Idle Tracking Switch (ITS) signal wire shorted to ground – ISC
(M) 1.9L MFI – PCM re-initialized. Possible electrical noise, case ground or intermittent VPWR problem – VPWR Diagnosis
(M) 3.8L AXOD – Data link to instrument cluster fault – See code 70
72 (R) No MAP or MAF change in “goose” test – retest, check for frequency or voltage change – MAP MAF
(M) 1.9L MFI – VPWR circuit to PCM was intermittent – VPWR Diagnosis
(M) 2.3L T/C – PCM re-initialized. Possible electrical noise, case ground or intermittent VPWR problem –  VPWR Diagnosis
(M) 3.8L AXOD – Message center data link circuit fault – See code 70
73 (O) Rerun test, if 73 is still output replace TPS
(R) No Throttle Position Sensor (TPS) change in “goose” test. Must get at least 25% throttle rotation – TPS
74 Was brake depressed after engine ID was received ?
Brake On Off (BOO) signal open or short to ground – BOO
75 Brake On Off (BOO) signal shorted to power – BOO
76 Vane Air Flow (VAF) did not respond to “goose” test – VAF
77 System did not receive “goose” test – see TESTS
78 (M) VPWR circuit to PCM was intermittent or the PCM is bad VPWR Diagnosis
79 A/C is on or pin 10 is shorted to power
80 SERIES CODES GENERALLY ARE CIRCUIT PROBLEMS THAT COULD BE WIRING, RELAY OR SOLENOID RELATED.
ONLY ONE OF THE CIRCUITS LISTED UNDER THE CODE IS USED ON EACH VEHICLE. THE FAULT IS IN WHICHEVER SOLENOID OR CIRCUIT IS PRESENT ON THE VEHICLE
81 Boost control solenoid – Solenoids
AIRD solenoid – Solenoids and Air Injection
3.0L SHO – Inlet Air Solenoid – Solenoids
82 2.3L TC – Fan Control wire shorted to ground – A/C and Fan Circuits
AIRB solenoid – Solenoids and Air Injection
3.8L SC – Super Charger Bypass Solenoid – Solenoids
83 High Electro Drive Fan circuit fault – A/C and Fan Circuits
EGR Control solenoid – Solenoids
3.0L SHO – Low Speed Fuel Pump Relay circuit – Power / Fuel Pump Circuits
84 EGR Vacuum Regulator – Solenoids
EGR cutoff solenoid – Solenoids
EGR Vent solenoid – Solenoids
85 2.3L T/C Automatic – 3/4-4/3 Shift solenoid – Transmissions
CANP solenoid (ALL 1989) – Solenoids
(M) 1.9L MFI – System has corrected rich condition – Fuel control
86 2.3L or 2.9L Truck – A4LD 3/4 shift solenoid – Transmissions
(M) 1.9L MFI – System has corrected lean condition – Fuel control
87 (O) Fuel pump circuit fault (check inertia switch) – Power / Fuel Pump Circuits
Vehicles with 2BBL carb – Temperature Compensated Accelerator Pump Solenoid – Solenoids
(M) intermittent in fuel pump primary circuit – Power / Fuel Pump Circuits
NOTE: On some Escorts with automatic seat belts this code is normal IN MEMORY due to the wiring
88 Throttle Kicker Solenoid – Solenoids
Variable Voltage Choke relay circuit fault – VVC
Fan Control circuit fault – A/C and Fan Circuits
A4LD – Converter Clutch Override solenoid – Transmissions
Electronic Ignition – IDM, DPI or spout circuit fault – Ignition Systems
89 A4LD – Converter Clutch Override solenoid – Transmissions
AXOD Torque Converter Control solenoid circuit – Transmissions
Exhaust Heat Control (heat riser) solenoid circuit – Solenoids
90
SERIES FUEL/AIR INJECTION CODES ON VEHICLES WITH DUAL OXYGEN SENSORS REFER TO THE LEFT OR FRONT SENSOR. EXCEPT: 1984-1988 3.8L ENGINES: RIGHT SENSOR
91 (R, M) System running lean – Fuel control
Transmission SS 1 circuit/solenoid problem – Transmissions
92 (R) System running rich – Fuel control
Transmission SS 2 circuit/solenoid problem – Transmissions
93 (O) Throttle linkage binding or bad ISC motor ISC (R) HO2S not reading – Fuel control
Transmission TCC circuit/solenoid problem – Transmissions
94 AIR system inoperative – Air Injection
Transmission TCC circuit/solenoid problem – Transmissions
95  (O) Fuel pump: open, bad ground or always on – Power / Fuel Pump Circuits
(R) AIR not Diverting (AIRD) – Air Injection
(M) Possible bad fuel pump ground or open between fuel pump and pin 8 at PCM (Fuel Pump Monitor signal) – Power / Fuel Pump Circuits
96 (O) Fuel pump monitor circuit shows no power – Power / Fuel Pump Circuits
(R) AIR Bypass (AIRB) not working – Air Injection
(M) (Service 87 code first if present) Fuel pump relay or battery power feed was open – Power / Fuel Pump Circuits
97 E4OD OD cancel light circuit failure – Transmissions
98  (R) Did not pass KOEO yet (Get 11 in KOEO first)
Transmission EPC circuit/solenoid failure – Transmissions
99 (R) ISC needs to learn (Let idle for 2 minutes; Erase memory and retest)
Transmission EPC circuit/solenoid failure – Transmissions

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 Valve Position Sensor
EGR  / 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

 

 

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