Lexus Trouble Codes OBD1

Lexus cars built before 1995 are equipped with the ODB1 diagnostic code malfunction identification system. What this means is once the car has had a malfunction in one of the engine or emission systems it will store a diagnostic trouble code. To gather these codes locate the diagnostic connector. This connector is located under the hood near the engine or on the passages side fender well. It will have a protective cover that can be lifted to the side when the clip is undone. Next identify the TE1 and TE terminals which are show under the cover and by the diagram below. 

Once the terminals have been identified insert a jumper wire. Next, turn the ignition key to the on position, the check engine light will start to flash. The first set of blinks will be the first position of the trouble code. Then a pause will occur and the next digit will start to flash. For example, if the check engine light flashes three time and then pauses and flashes one more time the code number would be 31. To clear trouble codes turn the ignition key off, remove the jumper wire and disconnect the negative battery cable for three minutes and reconnect.

Lexus Diagnostic Connector
Lexus Diagnostic Connector TE1 and TE Terminals

Code 12 and 13 Rpm signal circuit fault

Code 14 Igniter signal circuit fault

Code 16 ECT control signal fault

Code 21 and Code 28 Main oxygen sensor fault (for ES300; SC300 GS300 models)

Code 22 Coolant temperature circuit fault

Code 24 Intake temperature sensor circuit fault

Code 25 and Code 26 Air fuel ratio fault (for ES300 SC300 models)

Code 27 Sub-oxygen sensor circuit fault (for ES300 CA GS300 models)

Code 31 Low airflow meter voltage (for ES300 and GS300 models)

Code 32 High airflow meter voltage (for ES300 model)

Code 35 Barometric pressure sensor circuit fault (for GS300 SC300 models)

Code 41 and Code 47 Throttle position sensor circuit fault

Code 42 Vehicle speed sensor circuit fault

Code 43 Starter signal

Code 51 Switch condition signal fault (for ES300; GS300 SC300 models)

Code 52 Code 52 and Code 55 Knock sensor circuit fault

Code 71 EGR system circuit fault (for ES300; GS300 SC300 models)

Code 78 Fuel pump control circuit fault (for GS300 SC300 models)

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Article first published (Updated 2013-08-16)