MK2 Fault Codes

1. Obtaining Fault Codes.

2. Identifying the Fault Codes.

3. Clearing the Fault Codes.

1. Obtaining Fault Codes.

To get any fault code you have to access the ECU, which is in the passenger foot well.

Pull back the carpet (directly underneath the glove box).

You should now see the brass-coloured protective plate. The plate has a hole through to the ECU and you are able to view the LED through a plastic window.

Switch on the ignition (but don’t start the car).

As soon as the ignition is turned the red LED will give a short flash. Ignore this.

If there are no codes present the LED will remain unlit.
If there are codes, the LED will flash. An example of how it will flash is shown below:

You need to count the number of flashes, however there are two types – long and short. The long flashes represent tens and the short represent units. For example two long flashes and two short gives you code 22. (the different codes will be explained further on). There may also be more than one code – the ECU will pause for two seconds before transmitting the next code, if there is only one code it will pause for two seconds and repeat the same code.

2. Identifying the Fault Codes.

The number corresponds to the number of flashes.

1 Oxygen Sensor "A" (Primary) defective circuit or unplugged / defective sensor

2 Oxygen Sensor "B" defective circuit or unplugged / defective sensor

3 Manifold Absolute Pressure (MAP Sensor) defective circuit or unplugged / defective sensor

4 Crankshaft Angle Sensor (CAS) defective circuit or unplugged / defective sensor

5 Manifold Absolute Pressure (MAP Sensor) mechanical problem / disconnected piping

6 ECT Sensor (Engine Coolant Temperature) defective circuit or unplugged / defective sensor

7 Throttle Position Sensor (TPS) defective circuit or unplugged / defective sensor

8 TDC Position (Top Dead Centre Sensor) defective circuit or unplugged / defective sensor

9 CID Sensor (Number 1 Cylinder position) defective circuit or unplugged / defective sensor

10 IAT Sensor (Intake Air Temperature) defective circuit or unplugged / defective sensor

11 CO pot

12 EGR Lift Sensor (Exhaust Gas Recirculation) defective circuit or unplugged / defective sensor

13 APS Sensor (Atmospheric Pressure Sensor) defective circuit or unplugged / defective sensor

14 IAC/ISCV Valve (Idle Air Control/Idle Speed Control Valve) defective circuit or unplugged / defective sensor

15 Ignition Output Signal missing or defective ignition output signal

16 Fuel Injector System defective circuit or unplugged / defective fuel injector

17 VSS (Vehicle Speed Sensor) defective circuit or unplugged / defective sensor

18 Ignition Timing

19 Automatic Transmission Lock Up Control Solenoid Valve defective circuit or unplugged / defective solenoid valve

20 Electrical Load Detector (ELD)

21 VTEC Solenoid Valve defective circuit or unplugged / defective solenoid valve

22 VTEC Oil Pressure Switch defective circuit or unplugged / defective oil pressure switch

23 Knock Sensor (KS) defective circuit or unplugged / defective sensor

30 Automatic Transmission Signal: "A" / SEAF / SEFA / TMA or TMB

31 Automatic Transmission Signal "B"

41 Primary Oxygen Sensor – Heater circuit malfunction on D16Z6, D16Z7 and B16A2 engines

41 Linear Air Flow (LAF Sensor) heater malfunction on D15Z1 engine

43 Fuel Supply System defective or malfunctioning fuel supply system

45 System Too Lean or Too Rich malfunction in the fuel monitoring systems

48 Linear Air Flow (LAF Sensor) defective circuit or unplugged / defective sensor

54 CKF Sensor (Crankshaft Speed Fluctuation) defective circuit or unplugged / defective sensor

58 TDC Sensor 2 (Top Dead Centre) defective circuit or unplugged / defective sensor

61 Oxygen Sensor, Heated - Sensor 1 (Primary) high voltage, low voltage, or slow response

63 Oxygen Sensor, Heated - Sensor 2 (Secondary) high voltage, low voltage, or slow response

65 Oxygen Sensor Heater (Secondary) malfunctioning or defective oxygen sensor heater

67 Catalyst system Efficiency Below Threshold malfunctioning or defective catalyst system

70 Automatic Transmission malfunction with the automatic transmission controls

71 Cylinder 1 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

72 Cylinder 2 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

73 Cylinder 3 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

74 Cylinder 4 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

75 Cylinder 5 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

76 Cylinder 6 Misfire or a Random Misfire a condition is present that is creating a cylinder misfire

80 Exhaust Gas Recirculation insufficient flow detected

86 ECT Sensor (Engine Coolant Temperature) circuit range / performance problem

90 Evaporative Emission Control System leak detected in the fuel tank area

91 Fuel Tank Pressure Sensor low input.

92 Evaporative Emission Control System insufficient purge flow

3. Clearing the Fault Codes.

Before selling your family into slavery and rushing down to Honda to have your VTEC oil pressure switch replaced, you can clear the codes yourself. Just because there is a fault code present, it does not necessarily mean there is a fault. The ECU may just have missed a required signal and thrown up an error.

To reset the codes (and any adaptive values the ECU has stored) turn your ignition off and pull the 10A (FEUX DE DETRESSE HAZARD) fuse in the engine bay fuse box.

Remove it for 10 seconds and replace. That’s it - nothing else is needed. You can now check the LED again to see if the codes have gone. I suggest taking the car for a drive and then checking the codes again to see if any faults have come back. If the same code appears you may have a genuine fault, which would need to be investigated.

Scott Fowler.