How to: Ecu Error Codes

If you're having problems with your car stalling, hesitating, lacking power or if your engine check light has come on, it is likely there is something wrong with one of the many sensors under the hood and your ECU is showing a trouble code.

To check your ECU codes you need to pull the carpet up from the passenger's foot area to expose the ECU, it will still be covered by a metal plate but you are able to see the ECU code light which will flash to show you which code is the problem.

Your ECU Looks Like This:

The Arrow Shows The Light You Need To Look At

 

With the engine off and the key at the accessory position, have a look at the light. To show it's working, it should flick once when you turn the key to accessory. If the light is flashing, it means there is a trouble code, to determine which one, count the length and number of flashes.
A long flash indicates tens and a short flash indicates ones, so one long flash will mean code 10 and one fast flash shows code 1.
For example:    Flaaaaaash Flaaaaaash Flash    = code 21
Flaaaaaash Flash Flash            = code 12
Flash Flash Flash                    = code 3

To find out what each code means, check this table:

1) Primary oxygen sensor- Defective circuit or unplugged/ Defective sensor
2) Oxygen sensor "B"  - Defective circiut or unplugged/ Defective sensor
3) MAP (Manifold Absolute Pressure) Sensor - Defective circuit or unplugged/ Sensor
4) CKP (Crankshaft Position Sensor)  - Defective circuit or unplugged/ Defective sensor
5) MAP (Manifold Absolute Pressure) sensor -Mechanical problem/ Disconnected piping
6) ECT ( Engine Coolant Temperature) Sensor- Defective circuit or unplugged/ Sensor
7) TP (Throttle Position) Sensor -Defective circuit or unplugged/ Defective sensor
8) TDC (Top Dead Centre) Sensor -Defective circuit or unplugged/ Defective sensor
9) CYP (Cylinder) - Defective circuit or unplugged/ Defective sensor
10) IAT (Intake Air Temperature)sensor- Defective circuit or unplugged/Defective sensor
12) EGR (Exhaust Gas Recirculation) -Defective circuit or unplugged/ Defective sensor
13) Atmospheric Pressure Sensor - Defective circuit or unplugged/ Defective sensor
14) IAC (Intake Air 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
19) Automatic transmission lockup control Solenoid Valve- Defective circuit or unplugged/ Defective solenoid. A/T Only.
20) Electronic Load Detector - Defective circuit or unplugged/ Defective sensor
21) VTEC Solenoid Valve- Defective circuit or unplugged/ Defective solenoid
22) VTEC Oil Pressure Switch - Defective circuit or unplugged/ Defective switch
23) Knock Sensor - Defective circuit or unplugged / Defective sensor
30) Automatic Transmission Signal- Defective circuit or unplugged/ Defective sensor
31) Automatic Transmission Signal "B"- Defective circuit or unplugged/ Defective sensor
41) Primary Oxygen Sensor Heater- Circiut malfunction
43) Fuel Supply System - Defective or malfunctioning Fuel Supply Sytem
45) System too lean or too rich - Malfunction in the fuel monitoring systems
48) LAF (Lean Air Fuel) sensor - Defective circuit or unplugged / Defective sensor
54) CKF (Crankshaft Speed Fluctuation) sensor- Defective circuit or unplugged / Defective sensor
61) Primary Oxygen  sensor circuit- High/ Low Voltage, Or slow response
63) Secondary Oxygen Sensor circuit- High/ Low Voltage, Or slow response
67) Catalyst System Efficiency Below Threshold- Malfunctioning catalyst system
70) Automatic Transmission - Malfunction with Automatic Transmission Controls
71-74) Random misfire in Cylinders 1-4- Condition present Creating Misfire
80) EGR (Exhaust Gas Recirculation) Insufficient Flow Detected
86) ECT (Engine Coolant Temperature) Circuir Range / Performance Problem
90) Evaporative Emissions Contrlo System - Leak Detected In Fuel Tank Area
91) Fuel Tank Pressure Sensor- Low Input
92) Evaporative Emission Control System Control System- Insufficient Purge Flow

 

 

This website has been gradually growing since I started it in early 2002. Originally I was simply documenting modifications and repairs to my car but I decided to publish it when I began to discover others were interested in the information. If you need help or have a how-to relating to Honda B series VTEC engines, or DA or DC2R Integras you can
email me.

While all care is taken to provide correct information, mistakes are occasionally made and I cannot be responsible for any damage that occurs to readers vehicles.