General information
The engine control system constantly monitors the input signals from the various sensors in the injection system and compares them with defined limit values. If a signal violates these limits, the control unit stores the fault code in the memory. The trouble codes can be read out via the engine lamp or via LEDs on the control unit.
There are several different types of diagnosis form, fault code reading and fault code table. State which type of car you want diagnostic information about.
Reading trouble codes
To read the trouble codes on the following models:
CRX
1.5 l m/84-85
1.6 l m/86-87
Civic
1.5 l m/85-87
1.5 l DPI m/88-91
1.6 l MPI m/88-91
Accord
Exi m/86-88
2.0i m/88-90
Prelude
All models m/88-91
Legend
All models m/88-91
Apply as follows:
The car has no diagnostics socket. Any trouble codes are displayed automatically on the LEDs of the control unit. The control unit is located under the passenger seat.
Any trouble codes are displayed automatically when the ignition is switched on. The codes are read off on the diodes of the control unit. The control unit is located under the passenger seat.
To read the trouble codes on the following models:
Civic
All models m/92-97
Accord
All models m/90
All models m/91-97
Prelude
2.0i, 2.3i m/92-97
2.2 l VTEC m/96-97
Legend
All models m/91-97
Apply as follows:
The car has no diagnostics socket in the proper sense; instead it has a service socket. The service socket is located at the passenger side A-post under the glovebox.
Any trouble codes are read by first jumpering the two pins of the service socket. Then switch on the ignition. The trouble codes can be read out on the engine lamp or on the diode of the control unit.
The service socket is located at the passenger side A-post under the glovebox.
The control unit is located under the passenger seat.
Note also that the service socket must be jumpered at basic ignition setting adjustment.
Deleting trouble codes
To deleting the trouble codes on the following models:
CRX
1.5 l m/84-85
1.6 l m/86-87
Civic
1.5 l m/85-87
1.5 l DPI m/88-91
1.6 l MPI m/88-91
All models m/92-97
Accord
Exi m/86-88
2.0i m/88-90
All models m/90
All models m/91-97
Prelude
All models m/88-91
2.0i, 2.3i m/92-97
2.2 l VTEC m/96-97
Legend
All models m/88-91
All models m/91-97
Apply as follows:
Switch off the ignition
Disconnect the negative terminal from the battery or remove the control unit power supply fuse for at least 10 seconds
Connect the negative terminal/refit the fuse
Correct any faults in the system before deleting the trouble codes.
After deleting the codes, make sure that the fault has been corrected and deleted by starting the engine, warming it up thoroughly and then checking that no trouble codes are set.
Apperance of the trouble codes
On the following models:
CRX
1.5 l m/84-85
1.6 l m/86-87
Civic
1.5 l m/85-87
Accord
Exi m/86-88
Legend
All models m/88-91
The trouble codes appears as follows:
Any trouble codes are indicated on four LEDs on the control unit in accordance with the pattern below. The trouble codes are described in binary form.
On the following models:
Civic
1.5 l DPI m/88-91
1.6 l MPI m/88-91
Accord
2.0i m/88-90
Prelude
All models m/88-91
The trouble codes appears as follows:
Any trouble codes are indicated on an LED on the control unit in accordance with the pattern below.
On the following models:
Accord
All models m/90
All models m/91-97
Prelude
2.0i, 2.3i m/92-97
2.2 l VTEC m/96-97
Legend
All models m/91-97
The trouble codes appears as follows:
Any trouble codes are indicated on the engine lamp in accordance with the pattern below.
On the following models:
Civic
All models m/92-97
The trouble codes appears as follows:
Any trouble codes are indicated both on the engine lamp and on an LED on the control unit in accordance with the pattern below.
Trouble code list
Trouble codes for the following models:
CRX
1.5 l m/84-85
1.6 l m/86-87
Civic
1.5 l m/85-87
Accord
Exi m/86-88
Legend
All models m/88-91
Apply as follows:
Diode pattern | Code | Cause of the fault | Symptom |
0* | Control unit | Engine does not start | |
1 | Lambda sond | General malfunctions Lean running Rich running | |
2 | Speed sensor | No particular symptoms | |
3 | Map sensor | Poor engine response to throttle Low idling speed Engine tends to stall | |
4 | Idling contact | Rough, slow or fast idle | |
5 | Map sensor | Spark plugs tend to soot up Low idling speed Engine tends to stall | |
6 | Engine temperature sensor | Cold starting problems Idling speed to high while warming up | |
7 | Throttle contact | Poor engine response to throttle while warming up Idling speed tends to dip when throttle is opened Cold starting problems | |
8 | Speed sensor (ÖD) | Rough idling Poor engine response to throttle | |
9 | Cylinder identification sensor | Rough idling Poor engine response to throttle | |
10 | Induction air temperature sensor | Rough idling when engine is cold | |
11 | Mixture adjustment, idling (cars without catalytic converter) | No particular symptoms | |
13 | Pressure sensor, ATM | Reduced performance when driving at high altitudes | |
14 | Idling valve | Rough, slow or fast idling Idling speed tends to dip when throttle is opened |
* If the engine lamp is lit but no fault code is stored (fault code 0), this indicates a fault in the control unit.
Trouble codes for the following models:
Civic
1.5 l DPI m/88-91
1.6 l MPI m/88-91
All models m/92-97
Accord
2.0i m/88-90
All models m/90
Prelude
All models m/88-91
Apply as follows:
0* | ECU |
1 | Lambda sensor (except engine D16A9) |
3 | Map-sensor |
4 | Revolution sensor |
5 | Map-sensor |
6 | Coolant temperature sensor |
7 | Throttle potentiometer |
8 | Revolution sensor (ÖD) |
9 | Cylinder identification sensor cylinder 1 |
10 | Air inlet temperature sensor |
11 | Mixture adjustment idle (only engine D16A9) |
12 | EGR valve |
14 | Idel valve |
15 | Ignition pulse signal |
16 | Injection valve (D15B2) |
17 | Road speed sensor |
19 | Lock-up ventil (AT) |
20 | Electronic load control |
21 | Camshaft regulation valve |
22 | Oil pressure switch camshaft angle regulation |
41 | Heating lambda sensor (D16Z6, D16Z7, B16A2) |
41 | Heating LAF-sensor (D15Z1) |
43 | Fuel supply system (D16Z6, D16Z7, B16A2) |
48 | LAF sensor (D15Z1) |
* If the engine lamp is lit but no fault code is stored (fault code 0), this indicates a fault in the control unit.
Trouble codes for the following models:
Accord
All models m/91-97
Prelude
2.0i, 2.3i m/92-97
Apply as follows:
0* | ECU |
1 | Lambda sensor |
3 | Map-sensor |
4 | Revolution senosr |
5 | Map-sensor |
6 | Coolant temperature sensor |
7 | Throttle potentiomer |
8 | Revolution sensor (ÖD) |
9 | Cylinder identification sensor cylinder 1 |
10 | Air inlet temperature sensor |
11 | Mixture adjustment idle (only engine F22A2) |
12 | EGR valve |
13 | Pressure sensor, ATM |
14 | Idle valve |
15 | Ignition pulse signal |
17 | Road speed sensor |
20 | Electronic load control |
23 | Knock sensor (H23A1) |
30 | Automatic gearbox, signal A |
31 | Automatic gearbox, signal B |
41 | Heating lambda sensor |
43 | Fuel supply system |
* If the engine lamp is lit but no fault code is stored (fault code 0), this indicates a fault in the control unit.
Trouble codes for the following models:
Prelude
2.2 l VTEC m/96-97
Apply as follows:
0* | ECU |
1 | Lambda sensor (with cat.) |
3 | Map-sensor |
4 | Revolution sensor |
6 | Coolant temperature sensor |
7 | Throttle potentiometer |
8 | Revolution sensor (ÖD) |
9 | Cylinder identification sensor cylinder 1 |
10 | Air inlet temperature sensor |
11 | Mixture adjustment idle (without cat.) |
12 | EGR valve |
13 | Pressure sensor , ATM |
14 | Idle valve |
15 | Ignition pulse signal |
17 | Road speed sensor |
20 | Electronic load control (KM, KQ och KU) |
21 | Camshaft regulation valve, VTEC (H22A4, H22A5, H22A6) |
23 | Knock sensor (H22A4, H22A6) |
30 | Automatic gearbox, signal (AT) |
41 | Heating lambda sensor (with cat.) |
* If the engine lamp is lit but no fault code is stored (fault code 0), this indicates a fault in the control unit.
Trouble codes for the following models:
Legend
All models m/91-97
Apply as follows:
0* | ECU |
1 | Lambda sensor left (with cat.) |
2 | Lambda sensor right (with cat.) |
3 | Map-sensor |
4 | Revolution sensor 1 |
6 | Coolant temperature sensor |
7 | Throttle potentiometer |
9 | Cylinder identification sensor 1 (cylinder 1) |
10 | Air inlet temperature sensor |
11 | Mixture adjustment idle (without cat.) |
12 | EGR valve |
13 | Pressure sensor, ATM |
14 | Idle valve |
15 | Ignition pulse signal |
23 | Knock sensor left (not KG och KE) |
30 | Automatic gearbox, signal |
35 | Traction control signal, TC STB (TCS) |
36 | Traction control signal, TC FC (TCS) |
41 | Heating lambda sensor left |
42 | Heating lambda sensor right |
53 | Knock sensor right (not KG and KE) |
54 | Revolution sensor 2 |
59 | Cylinder identification sensor 2 (cylinder 1) |
63 | Secondary lambda sensor (KN) |
65 | Heating secondary lambda sensor (KN) |
70 | Automatic gearbox |
* If the engine lamp is lit but no fault code is stored (fault code 0), this indicates a fault in the control unit.