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OBD0 ECU codes and more

126K views 29 replies 21 participants last post by  Dave_Darling 
#1 ·
Actually found the answer to my own thread.

ECU Error Codes

Here's a handy chart for pulling your ECU codes. Pulling the code is a fairly easy process.
For 92+ Honda's and 94+ Acura's:

Before you can start reading the CEL (check engine light) in your dash, you need to 'jump' your ecu. Here's how.
Located the factory two-pin connector of brown and black wires near the ECU on Civics del Sols and Integra's, or behind the center console for Preludes and Accords. Pull that 2-pin out of the main harness. Using a wire or paper clip as a jumper, connect the outputs of the harness together, so that the black wire and the brown wire make a circuit. Once this is jumped together, the dash will start the light show, so its a good idea to jump first, then turn to on.

For 88-91 Honda's and 86-93 Acura's:

The ECU's on these cars actually have a neat little window right on the computer case. No need to jump here- just turn it to on, and watch it right there through that window.

For both steps above, the output will be in a Morse code style of long and short lights. For example, 2 long, pause, 3 short is 23.

1- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
Oxygen Sensor "A" (Primary)
defective circuit or unplugged / defective sensor

2- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-89 86-87 n/a 85-87 85-91 n/a n/a
Oxygen Sensor "B"
defective circuit or unplugged / defective sensor

3- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
MAP Sensor (Manifold Absolute Pressure)
defective circuit or unplugged / defective sensor

4- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-98 88-98 97-98 88-91 93-97 95-98 85-98
CKP Sensor (Crankshaft Position Sensor)
defective circuit or unplugged / defective sensor

5- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 * 86-98 97-98 85-91 93-97 96-98 85-98
MAP Sensor (Manifold Absolute Pressure)
mechanical problem / disconnected piping
* exc 94-95

6- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
ECT Sensor (Engine Coolant Temperature)
defective circuit or unplugged / defective sensor

7- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
TP Sensor (Throttle Position)
defective circuit or unplugged / defective sensor

8- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
TDC Sensor (Top Dead Center)
defective circuit or unplugged / defective sensor

9*- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98** 86-98 97-98 85-91 93-97 95-98 85-98
CYP Sensor (Cylinder)
defective circuit or unplugged / defective sensor
* not a valid code for any throttle body injection Hondas
** not a valid code for V-6 engines

10- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
IAT Sensor (Intake Air Temperature)
defective circuit or unplugged / defective sensor

12- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 * n/a 85-91 * n/a 95-98 85-98
EGR Lift Sensor (Exhaust Gas Recirculation)
defective circuit or unplugged / defective sensor
* not a valid code if car is not equipped with an EGR valve (some Civic models are not)

13- Accord Civic CRV CRX Del Sol Odyssey Prelude
85-98 86-98 97-98 85-91 93-97 95-98 85-98
BARO Sensor (Atmospheric Pressure)
defective circuit or unplugged / defective sensor

14- Accord Civic CRV CRX Del Sol Odyssey Prelude
88-98 88-98 97-98 88-91 93-97 95-98 88-98
IAC Valve (Idle Air Control)
defective circuit or unplugged / defective sensor

15- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-95 88-95 n/a 88-91 93-95 95 88-95
Ignition Output Signal
missing or defective ignition output signal

16- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-95 88-95 n/a 88-91 93-95 95 88-95
Fuel Injector System
defective circuit or unplugged / defective fuel injector

17- Accord Civic CRV CRX Del Sol Odyssey Prelude
88-98 88-98 97-98 88-91 93-97 95-97 88-98
VSS (Vehicle Speed Sensor)
defective circuit or unplugged / defective sensor

19- Accord Civic CRV CRX Del Sol Odyssey Prelude
n/a 88-95 n/a 88-91 93-97 n/a n/a
Automatic Transmission Lock Up Control Solenoid Valve
defective circuit or unplugged / defective solenoid valve

20- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-98 88-98 97-98 88-91 93-97 95-98 92-98
Electrical Load Detector
defective circuit or unplugged / defective sensor

21*- Accord Civic CRV CRX Del Sol Odyssey Prelude
94-98 ** 92-95 n/a n/a 93-95 n/a 93-95
VTEC Solenoid Valve
defective circuit or unplugged / defective solenoid valve
* not a valid code if car does not have a VTEC engine
** not with V-6 engine

22*- Accord Civic CRV CRX Del Sol Odyssey Prelude
94-98 92-98 n/a n/a 93-97 98 93-98`
VTEC Oil Pressure Switch
defective circuit or unplugged / defective oil pressure switch
* not a valid code if car does not have a VTEC engine

23- Accord Civic CRV CRX Del Sol Odyssey Prelude
98 * 96-98 n/a n/a 94-97 n/a 92-98
KS (Knock Sensor)
defective circuit or unplugged / defective sensor
* not a valid code if V-6 engine

30- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-98 * n/a n/a n/a n/a 95 92-98 *
Automatic Transmission Signal: "A" / SEAF / SEFA / TMA or TMB
defective circuit or unplugged / defective sensor
* not a valid code for 1996

31- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-95 n/a n/a n/a n/a 95 92-95
Automatic Transmission Signal "B"
defective circuit or unplugged / defective sensor

41- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-98 92-98 97-98 n/a 93-97 95-98 90-98
Primary Oxygen Sensor - Heater
circuit malfunction

43- Accord Civic CRV CRX Del Sol Odyssey Prelude
90-95 92-95 n/a n/a 93-95 95 90-95
Fuel Supply System
defective or malfunctioning fuel supply system

45- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
System Too Lean or Too Rich
malfunction in the fuel monitoring systems

48- Accord Civic CRV CRX Del Sol Odyssey Prelude
98 92-98 n/a n/a n/a n/a n/a
LAF Sensor (Lean Air Fuel)
defective circuit or unplugged / defective sensor

54- Accord Civic CRV CRX Del Sol Odyssey Prelude
96 96-98 97-98 n/a 96-97 n/a n/a
CKF Sensor (Crankshaft Speed Fluctuation)
defective circuit or unplugged / defective sensor

58- Accord Civic CRV CRX Del Sol Odyssey Prelude
98 * n/a n/a n/a n/a n/a n/a
TDC Sensor 2 (Top Dead Center)
defective circuit or unplugged / defective sensor
* with V-6 engine only

61- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Oxygen Sensor, Heated - Sensor 1 (Primary)
high voltage, low voltage, or slow response

63- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Oxygen Sensor, Heated - Sensor 2 (Secondary)
high voltage, low voltage, or slow response

65- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Oxygen Sensor Heater (Secondary)
malfunctioning or defective oxygen sensor heater

67- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Catalyst system Efficiency Below Threshold
malfunctioning or defective catalyst system

70- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a n/a 96-98 96-98
Automatic Transmission
malfunction with the automatic transmission controls

71- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Cylinder 1 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire

72- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Cylinder 2 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire

73- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Cylinder 3 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire

74- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
Cylinder 4 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire

75- Accord Civic CRV CRX Del Sol Odyssey Prelude
98 * n/a n/a n/a n/a n/a n/a
Cylinder 5 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
* valid code for V-6 engine only

76- Accord Civic CRV CRX Del Sol Odyssey Prelude
98 * n/a n/a n/a n/a n/a n/a
Cylinder 6 Misfire or a Random Misfire
a condition is present that is creating a cylinder misfire
* valid code for V-6 engine only

80- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 n/a n/a n/a 96-98 96-98
Exhaust Gas Recirculation
insufficient flow detected

86- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-98 96-98
ECT Sensor (Engine Coolant Temperature)
circuit range / performance problem

90- Accord Civic CRV CRX Del Sol Odyssey Prelude
97-98 96-98 n/a n/a n/a 98 97-98
Evaporative Emission Control System
leak detected in the fuel tank area

91- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 n/a n/a n/a 98 97-98
Fuel Tank Pressure Sensor
low input

92- Accord Civic CRV CRX Del Sol Odyssey Prelude
96-98 96-98 97-98 n/a 96-97 96-97 96-98
Evaporative Emission Control System
insufficient purge flow

----------------++++++++++++++++++++++++++++++------------------------------
85-87 obd0 codes

LED display Symptom - Possible Cause for 1985 through 1987 Honda Vehicles

Note: OOOO all 4 lamps on, XXXX all 4 lamps off

OOOO Engine will not start - Check for disconnected control unit ground connector. Also check for a loose connection at the ECU main relay resistor. Possible faulty ECU.

OOOO Engine will not start - Check for a short circuit in the combination meter or warning light wire. Also check for a disconnected control unit ground wire. Possible faulty ECU.

OOOX System does not operate - Faulty ECU

OOXO System does not operate - Faulty ECU

OOXX Fuel-fouled spark plugs, engine stalls frequently - Check for a disconnected MAP sensor coupler or an open circuit in the MAP sensor wire. Also faulty MAP sensor.

OXOO System does not operate - Faulty ECU.

OXOX Hesitation, fuel-fouled spark plugs or engine stalls frequently - Check for disconnected MAP sensor vacuum hose.

OXXO High idle speed during warm-up, continued high or hard starting at low temperature - Check for disconnected coolant temperature sensor connector or an open circuit in the coolant temperature sensor wire. Also faulty Coolant Temperature sensor.

OXXX Poor engine response when opening the throttle rapidly, high idle speed or engine does not rev-up when cold - Check for a disconnected throttle angle sensor connector. Also check for an open circuit in the throttle angle sensor wire. Also faulty throttle angle sensor.

XOOO Engine dose not rev-up, high idle speed or erratic idling - Check for a short or open in the crank angle sensor wire. Spark plug wires interfering with the crank angle sensor wire. Also faulty crank angle sensor.

XOOX Same as above (XOOO)

XOXO High idle speed or erratic idling when very cold - Check for disconnected intake air temperature sensor or an open circuit in the intake air temperature sensor wire. Also faulty Intake Air Temperature sensor.

XOXX Continued high idle speed - Check for a disconnected idle mixture adjuster sensor coupler or an open circuit in the idle mixture adjuster sensor wire. Also faulty Idle Mixture Adjuster sensor.

XXOO System does not operate at all - Faulty ECU

XXOX Poor acceleration at high altitude when cold - Check for a disconnected atmospheric pressure sensor coupler or an open circuit in the atmospheric pressure sensor wire. Also faulty Atmospheric Pressure Sensor.

XXXO System does not operate at all - Faulty ECU

XXXX Same as above (XXXO)

CODE PROBABLE CAUSE for Honda Vehicles 1988 and later.

0 Faulty ECU (no signal)

1 Oxygen sensor or circuit.

2 Faulty ECU

3 & 5 Manifold Absolute Pressure (MAP) sensor or circuit.

4 Crank angle sensor or circuit

6 Coolant temperature sensor or circuit

7 Throttle angle sensor or circuit.

8 TDC position/crank angle sensor or circuit.

9 Crank angle sensor or circuit

10 Intake air temperature sensor or circuit.

11 No particular symptom shown or system does not operate - faulty ECU

12 Exhaust gas recirculation (EGR) failure

13 Atmospheric pressure sensor circuit.

14 Electronic air control valve (EACV)

15 No ignition output signal - possible faulty igniter.

16 Fuel injector circuit.

17 Vehicle speed sensor or circuit (VSS)

19 Lock-up control solenoid valve (automatic transmission)

20 Electronic load detector - possible open or grounded circuit in ECU wiring.

21 VTEC spool solenoid valve circuit (Civic & Del-Sol)

22 VTEC oil pressure switch circuit (Civic & Del-Sol)

23 Knock sensor (Prelude)

30 A/T control unit ECM fuel injection signal "A" (Accord & Prelude)

31 A/T control unit ECM fuel injection signal "B" (Accord & Prelude)

41 Heated oxygen sensor - heater circuit.

43 Fuel supply system circuit (except D15Z1 engine)

45 Fuel system out of range - rich or lean

48 Heated oxygen sensor circuit (D15Z1 engine)

50 Mass airflow sensor.

61 Front oxygen sensor response slow.

63 Rear oxygen sensor circuit voltage out of range.

65 Rear oxygen sensor circuit malfunction.

67 Catalyic converter efficency low.

70 Automatic Transaxle problem.

71 through 76 Cylinder misfires

80 Insufficient EGR flow

86 Engine coolant temperature sensor circuit.

92 Evaporative emission purge valve problem
 
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#8 ·
i have an 88 crx si ...when i start the car the led light just keeps blinking and doesnt stop until i turn the car off of course....my check engine light only turns on after ten minutes of driving....if i turn the car off and turn it back on the check engine light is off....so how can i self diagnois what the prob is?
 
#15 ·
Omar said:
jfrolang said:
Omar said:
Mine blinked 13 times pretty fast then it paused and 1 blink after that. What is it?
Codes 13 and 1. Code 13 is rather rare, so maybe you just have it unplugged, or there's a corroded/shorted wire. In the worst case you can grab the sensor from any 4th gen Civic to replace it.
What sensor are you talking about? thanx
There are literally 4 lists in this thread that will tell you what the codes are, that's why I didn't go into detail.
 
#16 ·
christiank said:
i have an 88 crx si ...when i start the car the led light just keeps blinking and doesnt stop until i turn the car off of course....my check engine light only turns on after ten minutes of driving....if i turn the car off and turn it back on the check engine light is off....so how can i self diagnois what the prob is?
reallyquietman said:
My 1988 Si keeps blinking non-stop, I could expect that to be the oxygen sensor?
Either of you guys get this figured out? I have the same issue. 1990 Si.
 
#17 ·
reallyquietman said:
Krix said:
If it goes blink..pause..blink..pause..blink and keeps going like that it means a code 1/ oxygen sensor. If it is blink,blink,blink,blink very rapidly you have an entirely different problem.
My 1988 Si keeps blinking non-stop, I could expect that to be the oxygen sensor?
From what I heard, a single blink, pause single blink, pause..... means that there is no codes.... it does a single blink just to show you that its still working
 
#18 ·
aurelius said:
Either of you guys get this figured out? I have the same issue. 1990 Si.
NerdCore314 said:
From what I heard, a single blink, pause single blink, pause..... means that there is no codes.... it does a single blink just to show you that its still working
If there are no codes it blinks once when you start the car and thats it. If it blinks, pauses, and blinks once again thats code 1. It will keep repeating the sequence untill the problem is solved and the ECU is reset. (blink, pause, blink, pause, ect...)
 
#19 ·
Meech said:
aurelius said:
Either of you guys get this figured out? I have the same issue. 1990 Si.
NerdCore314 said:
From what I heard, a single blink, pause single blink, pause..... means that there is no codes.... it does a single blink just to show you that its still working
If there are no codes it blinks once when you start the car and thats it. If it blinks, pauses, and blinks once again thats code 1. It will keep repeating the sequence untill the problem is solved and the ECU is reset. (blink, pause, blink, pause, ect...)
Yeah I just took the rex to the shop today, they said I had the o2 sensor code right after replacing it because a ring was bad and getting oil all over the 02 sensor and it was making it pull up the code
 
#21 ·
SoFLcrx said:
Whats up guys, hopefully some one can help me out, 89 crx si, i was driving it for about 10 min and it randomly turned off and i got code 15, would you guys say i need a new distributor or something else such as a relay thanks in advance guys
code 15 is for the igniter in the distributor - could be you need to replace the igniter or could be a problem in the wiring
 
#22 ·
jlicrx said:
SoFLcrx said:
Whats up guys, hopefully some one can help me out, 89 crx si, i was driving it for about 10 min and it randomly turned off and i got code 15, would you guys say i need a new distributor or something else such as a relay thanks in advance guys
code 15 is for the igniter in the distributor - could be you need to replace the igniter or could be a problem in the wiring
Alright cool, after i let the car sit for a while it turned right back on idk if thatll help point to the source of the problem ? Thanks alot
 
#23 ·
So if the ECU blinks red just once when the car is started that means there is no problem at all? Just letting you know that it functions properly?
NerdCore314 said:
reallyquietman said:
Krix said:
If it goes blink..pause..blink..pause..blink and keeps going like that it means a code 1/ oxygen sensor. If it is blink,blink,blink,blink very rapidly you have an entirely different problem.
My 1988 Si keeps blinking non-stop, I could expect that to be the oxygen sensor?
From what I heard, a single blink, pause single blink, pause..... means that there is no codes.... it does a single blink just to show you that its still working
 
#24 ·
I have an 88 CRX SI. Check engine light started coming on once a month and has slowly increased to every time I drive it, about 5-15 minutes into my commute. The ECU under the passenger rug blinks as follows
[quick blink, long pause, quick blink, long pause, 20 quick blinks, long pause (repeat sequence)] = 1+1+20

My understanding is that the the blinks separated by the long pauses = 10, and the blinks in-between the long pause equal 1, but I'm not sure if my code is 20+20 (equaling 40) or if they are several sets of codes.

Any thoughts? Thank you!
 
#25 ·
all OBD0 ECUs for USDM D-series engines, like PM5, PM6, PM7, PM8, PM9, PG7, etc., use only short blinks, not long and short - sounds to me like you have a code 1 for the Oxygen sensor and a code 20 for the Electric Load Detector - reset the ECU and see if they come back
 
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