Pre-’96 Hondas are widely used to this day, and continue to prove their dependability without causing a huge hole in your wallet. They’re also very easy to troubleshoot, even when a check engine light occurs. Although post ’96 Hondas were equipped with diagnostic ports to be used in cooperation with an external OBD reader, pre ‘96s Hondas relayed error codes from their ECUs by flashing sequences via the check engine light on the gauge cluster.
How do you get the ECU to relay the codes? Simply by forming a bridge with a paper clip or stripped piece of wire between the two ports on your Honda’s diagnostic plug.
Follow this simple guide to learn what your Honda’s ECU is telling you.
Step 1: Locate Your Honda’s Diagnostic Plug
- Under the glove compartment, behind the passenger’s side kick panel, you’ll find either a blue or gray colored connector/plug that is not connected to anything. In some cases, depending on your particular model, the plug may be found on the driver’s side or behind the radio.
- Once located, carefully remove the plug from the rubber mount and plastic housing that’s bundling the wiring harnesses together.
Step 2: Create a Bridge
- Using either a paper clip, or a piece of wire with the tips stripped of insulation, arc the clip or wire and place an end into the holes of the clip on each side.
- Ensure the wire or clip is making contact with the actual wires by pressing the ends down into the holes of the plug.
Step 3: Decipher the Code
- With the bridge in place, turn your ignition forward to clicks to the “run” setting.
- The check engine light will begin to blink in a sequence of long and short blinks. A short blink entails “1” and a long blink entails “10.” Depending on the sequence given, you will add them together (i.e. if the check engine light gives one long blink and two short blinks, you will add 10,1,and 1 together, making 12.). Make sure to watch the check engine like carefully to ensure the proper count.
Step 4: Once you’ve learned the sequence, find it below to learn what’s wrong with your Honda.
- Code 0 & 11: Electronic Control Module (ECM)
- Code 1: Oxygen sensor A
- Code 2: Oxygen content B
- Code 3 & 5: Manifold Absolute Pressure (MAP)
- Code 4: Crank position sensor (CKP)
- Code 6: Engine coolant temperature (ECT)
- Code 7: Throttle position sensor (TPS)
- Code 8: Top dead center sensor (TDC)
- Code 9: No. 1 cylinder position sensor (CYP)
- Code 10: Intake air temperature sensor (IAT)
- Code 12: Exhaust gas recirculation system (EGR)
- Code 13: Barometric pressure sensor (BARO)
- Code 14: Idle air control valve or bad ECM (IAC)
- Code 15: Ignition output signal
- Code 16: Fuel injector
- Code 17: Vehicle speed sensor (VSS)
- Code 19: A/T lock-up control solenoid
- Code 20: Electric load detector
- Code 21: V-TEC control solenoid
- Code 22: V-TEC pressure solenoid
- Code 23: Knock sensor (KS)
- Code 30: A/T FI signal A
- Code 31: A/T FI signal B
- Code 41: Heated oxygen sensor heater
- Code 43: Fuel supply system
- Code 45: Fuel supply metering
- Code 48: Primary heated oxygen sensor
- Code 54: Crankshaft speed fluctuation sensor (CKF)
- Code 61: Front heated oxygen sensor
- Code 63: Rear heated oxygen sensor
- Code 65: Rear heated oxygen sensor heater
- Code 67: Catalytic converter system
- Code 70: Automatic transaxle
- Code 71: Misfire detected cylinder 1
- Code 72: Misfire detected cylinder 2
- Code 73: Misfire detected cylinder 3
- Code 74: Misfire detected cylinder 4
- Code 75: Misfire detected cylinder 5
- Code 76: Misfire detected cylinder 6
- Code 80: Exhaust recirculation system
- Code 86: Engine coolant temperature circuit (ECT)
- Code 91: Fuel tank pressure sensor low input
- Code 92: Evaporative emission control system
Now that you’ve learned why the dreaded check engine light has lit up on your Honda’s gauge cluster without breaking out the ol’ wallet, you can begin taking the necessary steps to replacing or repairing the faulty component. Save this guide to use as a reference for future check engine light occurences.