From 'Gregories w/shop manual : 93-97 Camry 4cyl.
Codes are presented by the 'Check engine warning light' as a series of flashes after the diagnosis connector is strapped to either 'normal' diagnosis or a more complicated 'test' diagnosis.
The 'normal' diagnosis:
1 ensure battery is more than 11volts 2 ensure throttle valve is closed 3 put trans in neutral 4 turn-off all accesoriesStart engine allow to reach normal op temperature. Assuming the 'check engine light' is on, stop the engine. Turn key to 'on' but do not start. Take off 'diagnosis connector' cap and with the aid of the terminal identification inside the cap bridge terminals TE1 and E1. Read code/s by counting the 'check engine light' flashes thusly:
The faults are displayed as a sequence by the flashing 'check engine light'. Each code comprises a series of 0.5 sec flashes, a 1.5 sec puase and a further series of 0.5 sec flashes. The first series in the set represent tens, the second series units. Example: Code 12 would be shown as one 0.5 sec flash, a 1.5 sec pause abd two 0.5 sec flashes. If more than one fault is in memory the codes will be grouped in nunerical order starting from the lowest number with each code separated by a 2.5 sec pause. If there are no faults in the memory, the 'check engine light' will flash continuously at .26 sec intervals. Codes:
12 Distributor NE or G sensor ciruit 13 Distributor NE sensor circuit 14 Igniter IGF or IGT circuit 16 Renew ECU (internal failure) 21 Oxygen sensor circuit 22* Colant temp sensor cuircuit 24* Intake air-temp sensor 25 Oxygen sensor (indicating lean mix 31* MAP sensor circuit 41* Throttle position sensor 42 Vehicle speed sensor 43 Starter signal circuit 52 Knock sensor circuitCodes marked * are for the 'test mode' diagnostics
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The more involved 'test mode' diagnostics requires a bit more messing about:
Repeat all the things as for 'normal test' with the exception of turning engine off and leaving off while terminals TE2 and E2 are bridged in the diag test connector (I think the original bridge is left in place). Switch on ignition. The 'check engine light' should flash rapidly to indicate 'test mode' Road test the vehicle and simulate the conditions when the fault previos;ly occured. The 'check engine light' will stay illuminated if a fault has been detected except for fault code 25 (Oxygen sensor circuit). Stop vehicle, switch to on but not start and bridge TE1 and E1 on the diagnosis connector and read as before.
To clear codes:
Switch ignition off and then remove the EFI fuse for 30 secs or more.