Preparatory Conditions
- Battery voltage 11 Volt minimum
- Closed throttle position (CTP) switch full closed
- Transmission in neutral position
- All auxiliary equipment, including air conditioning, switched OFF
- Engine at normal operating temperature
Accessing Trouble Codes
Self-Diagnosis – Normal Mode
- Switch ignition ON. Do NOT start engine.
- Check MIL illuminates
- Switch ignition OFF
- Corolla – jump DLC terminals TE1 and E1 with a short lead 1
- Celica – jump DLC terminals TE1 and E1 with a short lead 2
- Switch ignition ON
- Count MIL flashes and compare with trouble code table below
- First flashes of .5 second duration indicate ‘tens’, after a 1.5 second pause, next flashes of .5 second duration indicate ‘units’
- A 2.5 second pause occurs between codes
- After a 4.5 second pause, trouble codes will be repeated
- Switch ignition OFF
- Remove jump lead
Self-Diagnosis – Test Mode
- Carry out preparatory conditions
- Corolla – jump DLC terminals TE2 and E1 with a short lead 1
- Celica – jump DLC terminals TE2 and E1 with a short lead 2
- Switch ignition ON. Do NOT start engine
- Check MIL is flashing to confirm test mode is operating
- NOTE: Test mode will not be activated if the DLC terminals are connected after the ignition switch is turned ON.
- Start the engine
- Drive vehicle over 10 mph to simulate possible fault conditions
- Stop vehicle
- Jump DLC terminals TE1 and E1 with a short lead 1 or 2
- Count MIL flashes and compare with trouble code table below
- Switch ignition OFF
- Remove jump leads
Clearing Trouble Codes
- Ensure ignition switched OFF
- Corolla – remove EFI fuse (15A) from underhood fusebox 5
- Celica – remove EFI fuse (15A) from underhood fusebox 6
- Wait 30 seconds
- Reinstall fuse
- Repeat accessing procedure to ensure no data remains in ECM fault memory
Trouble Codes
| 94-95 Celica 1.8L Engine Code: 7A-FE |
| 94-95 Celica 2.2L Engine Code: 5S-FE |
| 93-95 Corolla 1.6L Engine Code: 4A-FE |
| 93-95 Celica 1.8L Engine Code: 7A-FE |
| Trouble code |
Fault location |
Probable cause |
| 12 |
Engine speed (RPM) sensor -circuit |
Wiring, RPM sensor, ECM |
| 13 |
Engine speed (RPM) sensor -above 1500 rpm |
Wiring, RPM sensor, ECM |
| 14 |
Ignition reference signal -no signal |
Wiring, ignition module, ECM |
| 16 |
Transmission control signal -malfunction |
EGM |
| 21 |
Heated oxygen sensor (H02S) -front circuit |
Wiring, H02S, ECM |
| 22 |
Engine coolant temperature (ECT) sensor -circuit |
Wiring, ECT sensor, ECM |
| 24 |
lntake air temperature (lAT) sensor -circuit |
Wiring, lAT sensor, ECM |
| 25 |
Mixture control -continuously lean |
Wiring, injector, H02S, intake/fuel ignition system, valve timing, ECM |
| 26 |
Mixture control -continuously rich |
Wiring, injector, intake/fuel system, valve timing, ECM |
| 27 |
Heated oxygen sensor (H02S)-rear-circuit |
Wiring, H02S, ECM |
| 31 |
Manifold absolute pressure (MAP) sensor -circuit |
Wiring, MAP sensor, ECM |
| 41 |
Throttle position (TP) sensor -circuit |
Wiring, TP sensor, ECM |
| 42 |
Vehicle speed sensor (VSS) -circuit |
Wiring, VSS, instrument c/uster, ECM |
| 43 |
Starter signal -circuit |
Wiring, ignition switch, engine control relay, ECM |
| 51 |
Switch signal -A/C switch ON during diagnosis |
Wiring, A/C switch, A/C amplifier, ECM |
| 51 |
Switch signal -closed throttle position (CTP) switch OFF during diagnosis |
Wiring, CTP switch, ECM |
| 51 |
Switch signal-park/neutra! position (PNP) switch not in P or N during diagnosis |
Wiring, PNP switch, ECM |
| 52 |
Knock sensor (KS) -circuit |
Wiring, KS, ECM |
| 71 |
Exhaust gas recirculation (EGR) system malfunction |
Hose leak/blockage, wiring, EGRT sensor, EGR solenoid, ECM |
