EEC IV Diagnostic Codes for Thunderbird & Cougar 1989-1997 by Gilbert (BeirutsFinest)   The following is a list of codes for the Ford EEC IV diagnostic test ONLY (1989-1997 Thunderbird & Cougar). These codes are not to be used for any other type of computer. These codes will help in the diagnosis of any problems you may have with your car. Some cars, (depending on year) give a 2 digit code, others give a 3 digit code, make sure you check how many digits your car gives before performing a diagnosis. Both 2 and 3 digit codes are listed below. As you will see below, there are various tests, KOEO, KOER, and Continuous memory codes, they are explained below. To get an accurate reading of your problem perform all 3 of these tests. Note: Always start with the first code displayed. Remember: Mechanical problems (ex: vacuum leaks) may make a good sensor look bad to the computer. Tests: O=Key On Engine Off (KOEO) (codes with engine off) C=Continuous Memory (codes stored when engine was running) R=Engine Running (codes produced as engine is running) Code Test Meaning 11 O,C,R System pass 12 R RPM not within self-test upper limit 13 R RPM not within self-test lower limit 14 C Profile Ignition Pickup circuit failure 15 O Read Only Memory test failed 15 C Keep Alive Memory test failed 16 R RPM too low to perform Oxygen sensor/fuel test (5.0L only) 18 C Loss of TACH input to ECA; SPOUT circuit grounded 18 R SPOUT circuit open 19 C Distributorless Ignition Cylinder identification circuit failure (3.8L SC only) 19 O Failure in EEC reference voltage (except 3.8L SC) 21 O,R Coolant Temperature Sensor (CTS) out of range 22 O,C,R Manifold Absolute/Baro Pressure Sensor out of range 23 O,R Throttle Position Sensor (TPS) out of range 24 O,R Air Charge Temperature (ACT) sensor out of range 25 R Knock sensor not sensed during Dynamic Response Test 26 O,R Mass Air Flow (MAF) sensor out of range 29 C No input from Vehicle Speed Sensor (VSS) 31 O,C,R EGR Valve Position (EVP) sensor out of range (low) 32 C,R EGR valve not seated; closed voltage low 33 C,R EGR valve not opening; insufficient flow detected 34 O,C,R EGR Valve Pressure Transducer/Position Sensor sonic voltage above closed limit 35 O,C,R EGR Valve Pressure Transducer/Position Sensor voltage out of range (high) 41 R,C Oxygen sensor circuit indicates system lean, right side 42 R Oxygen sensor circuit indicates system rich, right side 44 R Thermactor Air system inoperative, right side (5.0L only) 44 C Exhaust Gas Temperature Switch failed or catalyst over temperature (3.8L SC only) 45 C Coil Pack 1 (A) circuit failed (3.8L SC only) 45 R Thermactor Air upstream during self-test (5.0L only) 46 C Coil Pack 2 (B) circuit failed (3.8L SC only) 46 R Thermactor Air not by-passed during self-test (5.0L only) 47 C Spark location error (3.8L SC only) 48 C Coil Pack 3 (C) circuit failed (3.8L SC only) 49 C Default spark error (3.8L SC only) 51 O,C Coolant Temperature Sensor (CTS) circuit open 52 O,R Power Steering Pressure Switch circuit open 53 O,C Throttle Position Sensor (TPS) out of range (high) 54 O,C Air Charge Temperature (ACT) sensor circuit open 56 O,C Mass Air Flow (MAF) sensor out of range (high) 61 O,C Coolant Temperature Sensor (CTS) circuit grounded 63 O,C Throttle Position Sensor (TPS) circuit out of range (low) 64 O,C Air Charge Temperature (ACT) sensor circuit grounded 66 C Mass Air Flow (MAF) sensor circuit out of range (low) 67 C Clutch Switch circuit failed (3.8L SC only) 67 O Neutral Drive Switch circuit open 72 R Insufficient Mass Air Flow change during Dynamic Response Test 73 R Insufficient Throttle Position output during Dynamic Response Test 74 R Brake on/off switch failure 75 R Brake on/off circuit failure 77 R Wide Open Throttle (WOT) not sensed during self-test 79 O A/C on during self-test 81 O Air Management 2 circuit failure (5.0L only) 82 O Air Management 1 circuit failure (5.0L only) 82 O Supercharger By-pass Solenoid circuit failure (3.8L SC only) 83 O High Speed Electro Fan drive circuit failure (3.8L SC only) 84 O EGR Vacuum Regulator (EVR) circuit failure 85 O Canister Purge circuit failure 87 O,C Primary Fuel Pump circuit failure 88 O Electro Drive Fan circuit failure (3.8L SC only) 91 R,C Oxygen sensor indicates system lean, left side 92 R Oxygen sensor indicates system rich, left side 94 R Thermactor Air system inoperative, left side (5.0L only) 95 O,C Fuel Pump circuit open, ECA to motor 96 O,C Fuel Pump circuit open, battery to ECA 98 R Hard Fault present 111 O,C,R System Pass 112 O,C Air charge Temperature (ACT) sensor circuit below minimum voltage 113 O,C Air Charge Temperature (ACT) sensor circuit above maximum voltage 114 O,R Air Charge Temperature (ACT) sensor out of range 116 O,R Coolant Temperature Sensor (CTS) out of range 117 O,C Coolant Temperature Sensor (CTS) circuit below minimum voltage 118 O,C Coolant Temperature Sensor (CTS) circuit above maximum voltage 121 O,C,R Throttle Position Sensor (TPS) out of range 122 O,C Throttle Position Sensor (TPS) below minimum voltage 123 O,C Throttle Position Sensor (TPS) above maximum voltage 124 C Throttle Position Sensor (TPS) voltage higher than expected 125 C Throttle Position Sensor (TPS) voltage lower than expected 126 O,C,R Manifold Absolute/Baro Pressure sensor out of range 129 R Insufficient Manifold Absolute Pressure/Mass Air Flow change 136 R Indicates lean condition, left side 137 R Indicates rich condition, left side 139 C No Oxygen sensor switching detected, left side 144 C No Oxygen sensor switching detected, right side 157 C Mass Air Flow (MAF) sensor below minimum voltage 158 O,C Mass Air Flow (MAF) sensor above maximum voltage 159 O,R Mass Air Flow (MAF) sensor out of range 167 R Insufficient Throttle Position Sensor (TPS) change 171 C Oxygen sensor unable to switch, right side 172 R,C Oxygen sensor indicates lean condition, right side 173 R,C Oxygen sensor indicates rich condition, right side 174 C Oxygen sensor switching slow, right side 175 C Oxygen sensor unable to switch, left side 176 C Oxygen sensor indicates lean condition, left side 177 C Oxygen sensor indicates rich condition, left side 178 C Oxygen sensor switching slow, left side 179 C Adaptive fuel lean limit reached at part throttle, system rich, right side 181 C Adaptive fuel rich limit reached at part throttle, system lean, right side 182 C Adaptive fuel lean limit reached at idle, system rich, right side 183 C Adaptive fuel rich limit reached at idle, system lean, right side 184 C Mass Air Flow higher than expected 185 C Mass Air Flow lower than expected 186 C Injector pulse-width higher than expected 187 C Injector pulse-width lower than expected 188 C Adaptive fuel lean limit reached at part throttle, system rich, left side 189 C Adaptive fuel rich limit reached at part throttle, system lean, left side 191 C Adaptive fuel lean limit reached at idle, system rich, left side 192 C Adaptive fuel rich limit reached at idle, system lean, left side 211 C Profile Ignition Pickup (PIP) circuit fault 212 C Loss of TACH input to ECA; SPOUT circuit grounded 213 R SPOUT circuit open 214 C Distributorless Ignition System (DIS) cylinder identification circuit failure 215 C Coil 1 primary circuit failure (DIS) 216 C Coil 2 primary circuit failure (DIS) 217 C Coil 3 primary circuit failure (DIS) 219 C SPOUT circuit open; timing defaulted to 10 degrees 225 R Knock not sensed during Dynamic Response Test 311 R Thermactor Air system inoperative, right side 313 R Thermactor Air not by-passed 314 R Thermactor Air system inoperative, left side 326 C,R EGR circuit voltage lower than expected 327 O,C,R EGR Valve Pressure Transducer/Position sensor circuit below minimum voltage 328 O,C,R EGR Valve Position sensor voltage below closed limit 332 C,R EGR Valve opening not detected 334 O,C,R EGR Valve Position sensor voltage above closed limit 335 O EGR sensor voltage out of range 336 C,R EGR circuit voltage higher than expected 337 O,C,R EGR Valve Pressure Transducer/Position sensor circuit above maximum voltage 341 O Octane Adjust Service pin in use 411 R Unable to control RPM during low RPM self-test 412 R Unable to control RPM during high RPM self-test 452 C No input from Vehicle Speed Sensor (VSS) 511 O Read Only Memory test failed 512 C Keep Alive Memory test failed 513 O Internal voltage failure in ECA 522 O Neutral Drive Switch circuit open 525 O Indicates vehicle in gear, A/C on 528 C Clutch Switch circuit failure 536 O,R,C Brake on/off switch circuit failure 538 R Insufficient change in RPM 539 O A/C on during self-test 542 O,C Fuel pump circuit open; ECA to motor 543 O,C Fuel pump circuit open; battery to ECA 552 O Air Management 1 circuit failure 556 O,C Primary fuel pump circuit failure 558 O EGR Vacuum Regulator (EVR) circuit failure 563 O High Speed Electro Drive Fan circuit failure 564 O Electro Drive Fan relay circuit failure 565 O Canister Purge circuit failure 998 R Hard fault present   Back to homepage