Easy step by step method to retrieve Honda/Acura OBD1 trouble codes definitions.
Difficulty Level - 2
Method 1Step 1 - The most common method is to use the led light (sometimes 2 lights)
on the side of the computer itself. The colors are red and amber in most cases.
The red light is used for flashing codes and the amber light is used for fuel injection
adjustments. If the single led light indicator is present its used for flashing
trouble codes. The computer is located under the carpet on the passengers side in
the front floorboard in most cases. On other models the controller is located under
the driver's or passenger's front seat.
Method 2Step 1 - To retrieve codes use a jumper wire between the two ports on the diagnostic connector
located at the panel by passenger side foot well.
Step 2 - Next turn the key to the "ON" position allowing the dash lights
to illuminate without cranking the engine over.
Step 3 - Watch the light on the PCM and count the flashing
lights to decode the trouble code number. Example: Code 21 is 2 long light flashes
followed by 1 short flash. A long pause between the short flashes separates the
next code that follows.
Code Definition Table
Code 0 - Electronic control unit (ecu.)
Code 1 - 02 (oxygen) sensor.
Code 3 and 5 - Map sensor.
Code 4 - Crank angle sensor.
Code 6 - Coolant temperature sensor.
Code 7 - Throttle angle sensor TPS.
Code 9 - Cam angle sensor (CAS.)
Code 10 - Intake air temperature sensor.
Code 12 - EGR system fault.
Code 13 - Atmospheric pressure sensor.
Code 14 - Electronic air control valve.
Code 15 - Ignition output signal.
Code 16 - Fuel injector fault.
Code 17 - Vehicle speed sensor.
Code 21 - Spool solenoid valve.
Code 22 - Valve timing oil pressure switch fault.
Code 23 - Knock sensor.
Code 41 - Oxygen sensor heater fault.
Code 43 - Fuel pump supply system.
Written by Ken Lavacot Co-Founder and CEO of 2CarPros.com 35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.
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Article first published 2009-07-28 (Updated 2015-03-25)