PGM-FI System

DTC Troubleshooting (cont'd)

 11-263  

Any combination of the

DTC 71:

No. 1 Cylinder Misfire

DTC 72:

No. 2 Cylinder Misfire

DTC 73:

No. 3 Cylinder Misfire

DTC 74:

No. 4 Cylinder Misfire

NOTE: If the misfiring is frequent enough to damage the catalyst, the MIL will blink whenever the misfiring occurs. When the misfiring stops, the MIL will remain on.

  1. Troubleshoot the following DTCs first if any of them were stored along with the random misfire DTC(s) :

DTC 1: Primary Heated Oxygen Sensor

DTC 3: Manifold Absolute Pressure sensor

DTC 4: Crankshaft Position Sensor

DTC 12: EGR system

DTC 14: IAC Valve

DTC 21: VTEC System

DTC 45: Fuel System

  1. Test-drive the vehicle to verify the symptom.
  2. Find the symptom in the chart below, and do the related procedure in the order listed until you find the cause.

    Symptom

    Procedure(s)

    Also check for:

    Random misfire only at low engine speed and under load

    Test the fuel pressure (see page 11-131).
    • Low compression
    • Contaminated fuel

    Random misfire only during acceleration

    Test the fuel pressure (see page 11-131).

    Malfunction in the VTEC system (see page 6-9)

    Random misfire at high engine speed and load, or under random conditions

    Test the fuel pressure (see page 11-131).

    Correct valve clearance (see page 6-14)