DESCRIPTION
The following procedures are functional tests of EEC-IV system. There are 7 basic test steps. These test steps must be carefully followed in sequence, otherwise misdiagnosis or replacement of non-faulty components may result.
- Visual Check & Vehicle Preparation
- Equipment Hookup
- Key On Engine Off (KOEO) Self-Test
- Computed Timing Check
- Key On Engine Running (KOER) Self-Test
- Continuous Monitor Mode (Wiggle Test)
- Intermittents & Diagnosis By Symptom
Hardware Limited Operational Strategy (HLOS)
If a number of system or sensor failures are present, and the ECA is not receiving enough information to operate, ECA will switch to HLOS mode. ECA will output fixed values to allow operation of vehicle. Driveability concerns will be present. ECA will not output service codes in this mode.
FREQUENTLY USED EEC-IV ABBREVIATIONS
| Abbreviation | Definition |
|---|---|
| A/C | Air Conditioning |
| ACCS | A/C Cycling Switch |
| ACC | A/C Clutch Compressor |
| ACT | Air Charge Temperature sensor |
| ACV | Thermactor Air Control Valve |
| AXOD | Automatic Transaxle Overdrive |
| BOO | Brake On/Off switch |
| BP | Barometric Pressure sensor |
| CANP | Canister Purge solenoid |
| CCO | Converter Clutch Override |
| CFI | Central Fuel Injection |
| CID | Cylinder Identification sensor |
| CKT | Circuit |
| DIS | Direct Ignition System |
| DVOM | Digital Volt/Ohm Meter (see VOM) |
| ECA | Electronic Control Assembly, processor, computer |
| ECT | Engine Coolant Temperature sensor |
| EDF | Electric Drive Fan relay assembly |
| EEC | Electronic Engine Control |
| EGO | Exhaust Gas Oxygen sensor (see HEGO) |
| EGR | Exhaust Gas Recirculation system |
| EGRC | EGR Control solenoid or system |
| EGRV | EGR Vent solenoid or system |
| EVP | EGR Position sensor |
| EVR | EGR Valve Regulator |
| FI | Fuel Injector or Fuel Injection |
| FP | Fuel Pump |
| FPM | Fuel Pump Monitor |
| FWD | Front Wheel Drive |
| GND or GRND | Ground |
| HEDF | High Speed Electro Drive Fan relay or circuit |
| HEGO | Heated EGO sensor |
| HEGOG | HEGO Ground circuit |
| HO | High Output |
| HSC | High Swirl Combustion, engine type |
| IDM | Ignition Diagnostic Module |
| IGN | Ignition system or circuit |
| INJ | Injector or Injection |
| ISC | Idle Speed Control |
| ITS | Idle Tracking Switch |
| KAM | Keep Alive Memory |
| KAPWR | Keep Alive Power |
| KOEO | Key On Engine Off |
| KOER | Key On Engine Running |
| KS | Knock Sensor |
| L | Liter(s) |
| LOS | Limited Operation Strategy, computer function |
| LUS | Lock-Up Solenoid |
| MAF | Mass Air Flow sensor, meter or circuit |
| MAP | Manifold Absolute Pressure sensor |
| MA PFI | Mass Air Sequential Port Fuel Injection system |
| MCU | Microprocessor Control Unit |
| MIL | Malfunction Indicator Light |
| MPFI | Multi Point Fuel Injection |
| NDS | Neutral Drive Switch |
| NGS | Neutral Gear Switch |
| NPS | Neutral Pressure Switch |
| OCC | Output Circuit Check |
| OHC | Overhead Camshaft, engine type |
| OSC | Output State Check |
| PFE | Pressure Feedback EGR sensor or circuit |
| PFI | Port Fuel Injection |
| PIP | Profile Ignition Pickup |
| PSPS | Power Steering Pressure Switch |
| PWR GND | Power Ground circuit |
| RWD | Rear Wheel Drive |
| SC | Super Charged, engine type |
| PFI | Port Fuel Injection (see MA SEFI) |
| SIG RTN | Signal Return circuit |
| SIL | Shift Indicator Light |
| SPOUT | Spark Output Signal, from ECA |
| SS 3/4-4/3 | Shift Solenoid circuit |
| STAR | Self Test Automatic Readout, test equipment |
| STI | Self Test Input circuit |
| STO | Self Test Output circuit |
| TAB/TAD | Thermactor Air Bypass/Thermactor Air Diverter Tandem solenoid valves operated by separate circuits. |
| TFI | Thick Film Ignition system |
| TGS | Top Gear Switch (cancels SIL operation in top gear) |
| THS | Transmission Hydraulic Switch |
| TP/TPS | Throttle Position Sensor |
| TTS | Transmission Temperature Switch |
| VAF | Vane Air Flow sensor or circuit |
| VAT | Vane Air Temperature |
| VBATT | Vehicle Battery Voltage |
| VM | Vane Meter |
| VOM | Analog Volt/Ohm Meter (see DVOM) |
| VPWR | Vehicle Power supply voltage (regulated 10-14 volts) |
| VREF | Voltage Reference (ECA supplied reference voltage, 4-6 volts) |
| VSC | Vehicle Speed Control sensor or signal |
| VSS | Vehicle Speed Sensor or signal |
| WAC | WOT A/C Cut-off switch or circuit |
| WOT | Wide Open Throttle |
FREQUENTLY USED EEC-IV ABBREVIATIONS DEFINITIONS
See also:
• FUEL PRESSURE SPECIFICATIONS