Retrieving Codes using the Service Check Connector

The service check connector is under the glove box. It should normally be connected to the connector cover located under the glove box but it may have come loose or be tucked behind other wires or the speaker box. In that case you may need to pull back the carpet covering the subwoofer/amp box in the front area of the passenger footwell to see it as I did here.

You are looking for a two pin connector. The plastic connector itself is bright blue. The wire colors seem to vary by year. On my 1991 they were BLU and GRN/WHT. On some later years they are BLU and BRN/BLK. You have to look right near the connector to see the wire colors because  they are wrapped in black electrical tape. The best thing to do is just look for the bright blue connector.

Once you have found it, follow these steps to retrieve any trouble codes stored in the computer:

• Turn the car off.

• Use a jumper wire or bent paperclip to short the connector as shown in the photo at right.

• Turn the ignition on but do not start the car.

• Record the blinking frequency of any dash indicator lights.

• The control unit can indicate up to three problems (three trouble codes). It will show the last three codes recorded since it was reset by disconnecting power (either disconnecting the battery or pulling the appropriate fuse). The blinking frequency indicates the problem code. Long blinks indicate the main code, short blinks indicate the sub code.

• For further clarification

• If you miscount the blinking lights or want to double check it, simply cycle the ignition switch off and back on again and it will re-display the blinks from the beginning.

• When you have recorded the blinks, remove the shorting wire or paper clip from the service connector. If you start the car with the service check connector shorted the Check Engine light will come on.

• Refer to the appropriate troubleshooting guide for the system you are trying to diagnose for a list of the meaning of the various code numbers for that system.

• You may want to pull the fuse for at least three seconds to clear all trouble codes stored in the computer. That way you will know that any further codes are new and not the same codes you just retrieved.

MIL Code	Description	OBD II Code	Description
0	ECM	P1607 P1608	ECM Internal Circuit Failure A ECM Internal Circuit Failure B
1	Front HO2S	P0151 P0152	Front Primary HO2S Circuit Low Voltage (Bank 2 Sensor 1) Front Primary HO2S Circuit High Voltage (Bank 2 Sensor 1)
2	Rear HO2S	P0131 P0132	Rear Primary HO2S Circuit Low Voltage (Bank 1 Sensor 1) Rear Primary HO2S Circuit High Voltage (Bank 1 Sensor 1)
3	MAP Sensor	P0107 P0108	MAP Sensor Low Input MAP Sensor High Input
4	CKP Sensor Position A	P0335 P0336	CKP Sensor A Circuit Malfunction CKP Sensor A Range/Performance
5	MAP Sensor	P1128 P1129	MAP Lower Than Expected MAP Higher Than Expected
6	ECT Sensor	P0117 P0118	ECT Circuit Low Input ECT Circuit High Input
7	TP Sensor	P0122 P0123 P1121	TP Circuit Low Input TP Circuit High Input Throttle Position Lower Than Expected
9	CYP Sensor Position A	P1381 P1382	CYP Sensor A Intermittent Interruption CYP Sensor A No Signal
10	IAT Sensor	P0111 P0112 P0113	IAT Range/Performance Problem IAT Circuit Low Input IAT Circuit High Input
12	EGR Valve Lift Sensor	P1491 P1498	EGR Valve Lift Insufficient Detected EGR Valve Lift Sensor High Voltage
13	BARO Sensor	P1106 P1107 P1108	BARO Circuit Range/Performance Malfunction BARO Circuit Low Input BARO Circuit High Input
14	IAC Valve	P505	IAC System Malfunction
15	Ignition Output Signal
16	Fuel Injection
17	VSS	P0500	VSS Circuit Low Input
18	Ignition Timing Adjuster
21	Front VTEC Solenoid Valve
22	Front VTEC Pressure Switch	P1279	VTEC System Malfunction, Front Bank (Bank 2)
23	Front KS	P0330	Front KS Circuit Malfunction
30	A/T FI Signal A
31	A/T FI Signal B	P1671 P1672	A/T FI Data Line No Signal A/T FI Data Line Failure
35	TC STB Signal	P1676 P1677	Traction Control System FI Data Line No Signal Traction Control System FI Data Line Failure
36	TCFC Signal
37		P1246 P1247 P1248	Accelerator Position Sensor 1 Circuit Malfunction Accelerator Position Sensor 2 Circuit Malfunction Accelerator Position Sensors 1 & 2 Improper Correlation
40		P1241 P1242 P1243 P1244	Throttle Vent Control Motor Circuit 1 Malfunction Throttle Vent Control Motor Circuit 2 Malfunction Throttle Position Insufficient Closed Throttle Position Insufficient
41	Front HO2S Heater	P0155	Front Primary HO2S Heater Circuit Malfunction (Bank 2 Sensor 1)
42	Rear HO2S Heater	P0135	Rear Primary HO2S Heater Circuit Malfunction (Bank 1 Sensor 1)
43	Front Fuel Supply System
44	Rear Fuel Supply System
45	Front Fuel Metering	P0174 P0175	System Too Lean, Front Bank (Bank 2) System Too Rich, Front Bank (Bank 2)
46	Rear Fuel Metering	P0171 P0172	System Too Lean, Rear Bank (Bank 1) System Too Rich, Rear Bank (Bank 1)
47	Fuel Pump
51	Rear VTEC Solenoid Valve
52	Rear VTEC Pressure Switch	P1259	VTEC System Malfunction, Rear Bank (Bank 1)
53	Rear KS	P0325	Rear KS Circuit Malfunction
54	CKP Sensor Position B	P1336 P1337	CKP Sensor B Range/Performance CKP Sensor B Low Input
59	CYP Sensor Position B	P1386 P1387	CYP Sensor B Intermittent Interruption CYP Sensor B No Signal
61		P0153	Front Primary HO2S Slow Response (Bank 2 Sensor 1)
62		P0133	Rear Primary HO2S Slow Response (Bank 1 Sensor 1)
63		P0157 P0158 P0159	Front Secondary HO2S Circuit Low Voltage (Bank 2 Sensor 2) Front Secondary HO2S Circuit High Voltage (Bank 2 Sensor 2) Front Secondary HO2S Circuit Slow Response (Bank 2 Sensor 2)
64		P0137 P0138 P0139	Rear Secondary HO2S Circuit Low Voltage (Bank 1 Sensor 2) Rear Secondary HO2S Circuit High Voltage (Bank 1 Sensor 2) Rear Secondary HO2S Slow Response (Bank 1 Sensor 2)
65		P0161	Front Secondary HO2S Heater Circuit Malfunction (Bank 2 Sensor 2)
66		P0141	Rear Secondary HO2S Heater Circuit Malfunction (Bank 1 Sensor 2)
67		P0430	Front Catalyst System Efficiency Below Threshold
68		P0420	Rear Catalyst System Efficiency Below Threshold
70		P0700, P0715 P0720, P0725 P0730, P0740 P0753, P0758 P1705, P1706 P1753, P1758 P1768, P1788 P1790, P1791 P1792, P1793 P1795	A/T
71		P0300, P1300 P1201, P1301	Random Misfire Cylinder 1 Misfire
72		P0300, P1300 P1202, P1302	Random Misfire Cylinder 2 Misfire
73		P0300, P1300 P1203, P1303	Random Misfire Cylinder 3 Misfire
74		P0300, P1300 P1204, P1304	Random Misfire Cylinder 4 Misfire
75		P0300, P1300 P1205, P1305	Random Misfire Cylinder 5 Misfire
76		P0300 P1206, P1306	Random Misfire Cylinder 6 Misfire
79		P1316 P1317 P1318 P1319	Spark Plug Voltage Detection Circuit Malfunction, Front Bank Spark Plug Voltage Detection Circuit Malfunction, Rear Bank Spark Plug Voltage Detection Module Reset Circuit Malfunction, Front Bank Spark Plug Voltage Detection Module Reset Circuit Malfunction, Rear Bank
80		P0401	EGR Insufficient Flow
86		P0116	ECT Circuit Range/Performance
90		P1456 P1457	Evaporative Emission Control System Leak Detected (Fuel Tank System) Evaporative Emission Control System Leak Detected (Control Canister System)
91		P0452 P0453	Fuel Tank Pressure Sensor Circuit Low Input Fuel Tank Pressure Sensor Circuit High Input