Frequently Asked Question

All OBD0, OBD1, and OBD2 Honda and Acura vehicles will give a "check engine light" when a diagnostic error occurs. The following is a complete list of codes to help you diagnose your check engine light.

OBD 0/1/2 CEL CODES:

0 - ECU - Faulty ECU or ECU ROM Diagnostic Procedure
1 - O2A - Oxygen sensor #1
2 - O2B - Oxygen sensor #2
3 - MAP - manifold absolute pressure sensor
4 - CKP - crank position sensor
5 - MAP - manifold absolute pressure sensor
6 - ECT - water temperature sensor
7 - TPS - throttle position sensor
8 - TDC - top dead center sensor
9 - CYP - cylinder sensor
10 - IAT - intake air temperature sensor Diagnostic Procedure
11 - engine overheating
12 - EGR - exhaust gas recirculation lift valve
13 - BARO - atmospheric pressure sensor
14 - IAC (EACV) - idle air control valve
15 - Ignition output signal
16 - Fuel injectors
17 - VSS - vehicle speed sensor
19 - Automatic transmission lockup control valve
20 - ELD - Electrical load detector
21 - VTEC spool solenoid valve
22 - VTEC pressure valve
23 - Knock sensor
30 - Automatic transmission A signal
31 - Automatic transmission B signal
36 - Traction control found on some JDM ecu's
38 - Secondary VTEC solenoid on JDM 3 stage D15B Vtec ECUs (P2J)
41 - Primary oxygen sensor heater
43 - Fuel supply system
45 - Fuel system too rich or lean
48 - LAF - lean air fuel sensor
54 - CKF - crank fluctuation sensor
58 - TDC sensor #2
61 - Primary oxygen sensor
63 - Secondary oxygen sensor circuit
65 - Secondary oxygen sensor heater wire (black wires)
67 - Catalytic Converter
71 - random misfire cylinder 1
72 - random misfire cylinder 2
73 - random misfire cylinder 3
74 - random misfire cylinder 4
80 - EGR Valve/Line
86 - ECT sensor - Cooling System
91 - Fuel Tank pressure sensor
92 - EVAP Solenoid/Valve/Vacuum Lines


OBD1 TCU CODES:

1 - Lock-up solenoid 'A' circuit open or shorted
2 - Lock-up solenoid 'B' circuit open or shorted
3 - Throttle Position Sensor circuit open or shorted
4 - Vehicle Speed Sensor open or shorted - No signal from speedometer
5 - Shift Lever Position Switch circuit shorted
6 - Shift Lever Position Switch circuit open
7 - Shift Solenoid 'A' circuit open or shorted
8 - Shift Solenoid 'B' circuit open or shorted
9 - Counter shaft or transmission speed pulse generator open or shorted
10 - Coolant Temperature Sensor open or shorted
11 - Engine RPM (Ignition coil signal) open or shorted
12 - (No code 12 used)
13 - Main shaft speed pulse generator open or shorted
14 - Linear (line pressure control) solenoid open or shorted
15 - Kick down switch circuit shorted