Engine Controls - Tests W/codes: Other Subaru SVX I

HARD FAILURES

Hard failures cause CHECK ENGINE light to glow and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic (code) charts. If a sensor fails, control unit will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, vehicle runs but driveability will not be optimum.

INTERMITTENT FAILURES

Intermittent failures may cause CHECK ENGINE light to flicker or glow and go out after intermittent fault goes away. However, corresponding trouble code will be retained in ECU memory. If related fault does not reoccur within a certain time frame, related trouble code will be erased from ECU memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in TESTS W/O CODES article.

RETRIEVING CODES

1. Enter specific test mode by connecting or disconnecting read memory and/or test mode connectors as shown in the «RELATIONSHIP BETWEEN MODES & CONNECTORS»(ref-26045-S38193249982001010500000) table. Connectors are located behind left side of instrument panel. (Scheme 7)
2. Observe malfunction indicator light (CHECK ENGINE light) or O2 sensor monitor light. Note any trouble codes. Long illumination periods of 1.2 seconds designate tens digit in numbered codes. Short illumination periods of.2 second designate ones digit in numbered codes.
3. Tens and ones digits are separated by a.3-second interval of non-illumination. For example: 3 long flashes (1.2 seconds each) followed by 5 short flashes (.2 second each) designate code 35.
4. After a 2-second break, another code will be displayed. Once all existing codes have been displayed, sequence will repeat.

RELATIONSHIP BETWEEN MODES & CONNECTORS

Scheme 7

CLEARING CODES

After malfunction has been corrected, trouble code will clear from memory when CLEAR MEMORY mode is accessed. Unless all items check okay in D-CHECK mode, memory will not be cleared. Refer to the RELATIONSHIP BETWEEN MODES & CONNECTORS table.

SUMMARY

If no hard fault codes (or only pass codes) are present, driveability symptoms exist or intermittent codes exist, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

Scheme 8

CODE 11: CRANK ANGLE SENSOR NO. 1

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to OFF position. Disconnect ECU connectors. Turn ignition switch to ON position. Using a DVOM set to low-volt AC scale, check for voltage variation between ECU connector B61, terminals No. 1 and 2 while cranking engine. Voltage variation should be 0.1 volt or greater and should be synchronous with RPM. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector is okay, replace ECU.
2. Turn ignition switch to OFF position. Remove alternator. Disconnect crank angle sensor No. 1 connector. Using an ohmmeter, check resistance between ECU connector B61, terminal No. 1 and crank angle sensor connector terminal No. 2 (White wire), and between ECU connector B61, terminal No. 2 and crank angle sensor connector terminal No. 1 (Black wire). Resistance should be zero ohms for both circuits.
3. Check resistance between ground and ECU connector B61, terminals No. 1, 2 and 3. Resistance should be at least one megohm at each terminal. If resistances are as specified, go to next step. If resistances are not as specified, repair appropriate circuit as necessary.
4. Remove crank angle sensor. Connect oscilloscope positive lead to sensor terminal No. 1 (Black wire), and negative lead to sensor terminal No. 2 (White wire). While moving magnet over crank angle sensor pick-up coil, check oscilloscope wave pattern. If wave pattern exists, malfunction is mechanical. If wave pattern does not exist, replace crank angle sensor No. 1.

CODE 12: STARTER SWITCH

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to START position. Ensure starter motor is operating. If starter motor is operating correctly, go to step 4). If starter motor is not operating correctly, check inhibitor switch operation. Turn ignition switch to OFF position. Disconnect inhibitor switch connector, located near transaxle dipstick.
2. Using an ohmmeter, check resistance between connector terminals No. 11 (Black/White wire) and No. 12 (Black/Yellow wire). Resistance should be zero ohms with transaxle in Park or Neutral. Resistance should be at least 1000 ohms when transaxle is shifted into any other position. If resistance is as specified, go to next step. If resistance is not as specified, repair inhibitor switch as necessary.
3. Inspect starter assembly and repair as necessary. If starter assembly is okay, inspect and repair starter power supply circuit. Ensure vehicle security system is operating properly. Repair as necessary.
4. Turn ignition switch to OFF position. Disconnect ECU connectors. Using a DVOM, check voltage between ECU connector B61, terminal No. 10, and ground while cranking engine.
5. Voltage should be 9-12 volts. If voltage is not as specified, repair circuit between ECU connector and starter assembly. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.

CODE 13: CAM ANGLE SENSOR

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to OFF position. Disconnect ECU connectors. Check ECU input signal for cam angle sensor. Using a DVOM set to low-volt AC scale, check for voltage variation between ECU connector B59, terminals No. 7 and 9 while cranking engine. Voltage variation should be at least 0.1 volt and should be synchronous with RPM. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
2. Turn ignition switch to OFF position. Disconnect cam angle sensor connector. Using an ohmmeter, check resistance between ECU connector B59, terminal No. 7 and cam angle sensor connector terminal No. 1 (Black wire), and between ECU connector B59, terminal No. 9, and cam angle sensor connector terminal No. 2 (White wire). Resistance should be zero ohms for each circuit. If resistance is as specified, go to next step. If resistance is not as specified, repair appropriate circuit as necessary.
3. Check resistance between ground and ECU connector B59, terminals No. 7 and 9. Resistance should be one megohm or greater at each terminal. If resistance is as specified, go to next step. If resistance is not as specified, repair circuit as necessary.
4. Remove cam angle sensor. Connect oscilloscope positive lead to sensor terminal No. 1 (Black wire), and negative lead to sensor terminal No. 2 (White wire). While moving magnet over cam angle sensor pick-up coil, check oscilloscope wave pattern. If wave pattern exists, malfunction is mechanical. If wave pattern does not exist, replace cam angle sensor.

CODES 14, 15, 16, 17, 18 & 19: FUEL INJECTORS

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. While cranking engine, ensure operating sound is heard at each injector. If operating sound is heard, check system fuel pressure. See BASIC TESTING article. If operating sound is not heard, check power supply to each injector. Turn ignition switch to OFF position. Disconnect connector from each injector. Turn ignition switch to ON position.
2. Using a DVOM, check voltage between each injector connector terminal No. 2 (White/Red wire) and ground. Reading should be at least 10 volts at each terminal. If voltage is as specified, go to next step. If voltage is not as specified, repair appropriate circuit as necessary.
3. Turn ignition switch to OFF position. Using an ohmmeter, check resistance for each injector. Resistance should be 11-12 ohms. If resistance is as specified, go to next step. If resistance is not as specified, replace appropriate injector.
4. Turn ignition switch to OFF position. Connect each fuel injector connector. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and ECU connector B62, terminals No. 11, 12, 13 and 26. Check voltage between ground and ECU connector B59, terminals No. 1 and 12. Reading should be at least 10 volts for each injector. If voltage is as specified, go to next step. If voltage is not as specified, repair appropriate circuit as necessary.
5. Turn ignition switch to OFF position. Disconnect ECU connector. Using an ohmmeter, check resistance between ground and ECU connector B62, terminals No. 24 and 25. Resistance should be zero ohms. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, check ECU connector terminals for good contact. Repair as necessary. If ECU connector terminals are okay, replace ECU.

CODE 21: COOLANT (WATER) TEMPERATURE SENSOR

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Remove collector cover and air intake boot. Disconnect coolant temperature sensor connector. Using an ohmmeter, check sensor resistance. Resistance should be 30,000 ohms at 68°F (20°C) and 400 ohms at 176°F (80°C). If resistance is as specified, go to next step. If resistance is not as specified, replace coolant temperature sensor.
2. Turn ignition switch to OFF position. Disconnect ECU connectors. Check resistance between ECU connector B59, terminal No. 3 and sensor connector terminal No. 1 (Gray/Yellow wire), and between ECU connector B59, terminal No. 21 and sensor connector terminal No. 2 (Blue/Black wire)
3. Resistance should be zero ohms for all circuits. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.

CODE 22: KNOCK SENSOR NO. 1

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B61, terminal No. 5 (backprobe) and ground. Voltage should be 2-3 volts. If voltage is as specified, go to next step. If voltage is not as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
2. Turn ignition switch to OFF position. Remove collector and disconnect knock sensor connector, located on side of block. Using an ohmmeter, check resistance between knock sensor terminal and ground. Resistance should be about 560,000 ohms. If resistance is as specified, repair circuit between ECU and knock sensor. If resistance is not as specified, replace knock sensor.

CODE 23: AIRFLOW SENSOR

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Check ECU input signal for airflow sensor. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B60, terminal No. 5 (backprobe) and ground. Voltage should be 0-0.3 volts. Check voltage between ECU connector B60, terminal No. 6 (backprobe) and ground. Voltage should not exist. Check voltage between ECU connector B59, terminal No. 11 (backprobe) and ground. Voltage should be 10-13 volts.
2. With engine idling, check voltage between ECU connector B60, terminal No. 5 and ground. Voltage should be 0.8-1.2 volts. Check voltage between ECU connector B60, terminal No. 6 and ground. Voltage should not exist. Check voltage between ECU connector B59, terminal No. 11 and ground. Voltage should be 13-14 volts.
3. If voltage is as specified in previous steps, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU. If voltage is not as specified in previous steps, turn ignition switch to OFF position. Disconnect ECU and airflow sensor connectors.
4. Using an ohmmeter, check resistance between ECU connector B59, terminal No. 11 and sensor connector terminal No. 3 (Black/Red wire), between ECU connector B60, terminal No. 4 and sensor connector terminal No. 1 (Red wire), between ECU connector B60, terminal No. 5 and sensor connector terminal No. 4 (White wire), and between ECU connector B60, terminal No. 6 and sensor connector terminal No. 2 (Black wire).
5. Resistance should be zero ohms for all circuits. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, replace airflow sensor.

CODE 24: BY-PASS AIR CONTROL SOLENOID VALVE

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B62, terminal No. 14 (backprobe) and ground. Voltage should be 10 volts or greater. If voltage is as specified, go to step 4). If voltage is not as specified, go to next step.
2. Turn ignition switch to OFF position. Disconnect ECU and main relay connectors. Using an ohmmeter, check resistance between ECU connector B62, terminal No. 14 and main relay connector terminal No. 4 (Black/White wire). Resistance should be zero ohms. If resistance is as specified, go to next step. If resistance is not as specified, repair circuit as necessary.
3. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and main relay connector terminals No. 1 (Black/White wire) and No. 2 (Brown/Black wire). Voltage should be 10 volts or greater at each terminal. If voltage is not as specified, repair appropriate circuit as necessary. If voltage is as specified, replace main relay.
4. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and ECU connector B62, terminals No. 1 and 2. Voltage should be 6 volts or greater at terminal No. 1, and 7 volts or greater at terminal No. 2. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
5. Turn ignition switch to OFF position. Remove throttle body from collector. Disconnect by-pass air control solenoid valve connector. Using an ohmmeter, check resistance between ECU connector B62, terminal No. 1 and solenoid valve connector terminal No. 1 (White wire), and between ECU connector B62, terminal No. 2 and solenoid valve connector terminal No. 3 (White/Black wire). Resistance should be zero ohms for both circuits. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, replace solenoid valve.

CODE 28: KNOCK SENSOR NO. 2

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B61, terminal No. 6 and ground. Voltage should be 3-4 volts. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
2. Remove collector and disconnect knock sensor connector, located on side of block. Using an ohmmeter, check resistance between knock sensor terminal and ground. Resistance should be about 560,000 ohms. If resistance is as specified, repair circuit between ECU and knock sensor. If resistance is not as specified, replace knock sensor.

CODE 29: CRANK ANGLE SENSOR NO. 2

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to OFF position. Disconnect ECU connectors. Check ECU input signal for crank angle sensor No. 2. Turn ignition switch to ON position. Using a DVOM set to low-volt AC scale, check for voltage variation between ECU connector B59, terminals No. 8 and 9 while cranking engine. Voltage variation should be 0.1 volt or greater and be synchronous with RPM. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
2. Turn ignition switch to OFF position. Remove alternator. Disconnect crank angle sensor No. 2 connector. Using an ohmmeter, check resistance between ECU connector B59, terminal No. 8 and crank angle sensor connector terminal No. 2 (Black wire), and between ECU connector B59, terminal No. 9 and crank angle sensor connector terminal No. 1 (Yellow wire).
3. Resistance should be zero ohms for both circuits. Check resistance between ground and ECU connector B59, terminals No. 8, 9 and 10. Resistance should be one megohm or greater at each terminal. If resistance is as specified, go to next step. If resistance is not as specified, repair appropriate circuit as necessary.
4. Remove crank angle sensor. Connect oscilloscope positive lead to sensor terminal No. 1 (Yellow wire), and negative lead to sensor terminal No. 2 (Black wire). While moving magnet over crank angle sensor pick-up coil, check oscilloscope wave pattern. If wave pattern exists, malfunction is mechanical. If wave pattern does not exist, replace crank angle sensor No. 2.

CODE 31: THROTTLE POSITION SENSOR

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to OFF position. Disconnect throttle position sensor connector. Using an ohmmeter, check resistance between sensor terminals No. 1 (Red wire) and No. 3 (Black wire). Resistance should be 5000 ohms. Check resistance between sensor terminals No. 2 (White wire) and No. 3 (Black wire), while slowly opening throttle valve from closed position.
2. Resistance should be 10,000-12,000 ohms at fully closed throttle and 3000-5000 ohms at fully open throttle. Resistance should increase in response to throttle valve opening. If resistance is as specified, go to next step. If resistance is not as specified, replace throttle position sensor.
3. Disconnect ECU connectors. Using an ohmmeter, check resistance between ECU connector B60, terminal No. 1 and sensor connector terminal No. 3 (Black wire), between ECU connector B60, terminal No. 2 and sensor connector terminal No. 1 (Red wire), and between ECU connector, terminal No. 3 and sensor connector terminal No. 2 (White wire). Resistance should be zero ohms.
4. Check resistance between ground and connector terminals No. 1, 2 and 3. Resistance should be one meohm or greater at each terminal. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.

CODE 32: OXYGEN (02) SENSOR NO. 1

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Using a DVOM, check voltage between ground and B59, terminal No. 6 with engine idling. Voltage should vary between 0.1 volt and 1.0 volt. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
2. With engine at idle, disconnect oxygen sensor connector, located on right side of engine. Using a DVOM, check voltage between sensor connector terminal No. 4 (White wire) and ground. Voltage should vary between 0.1 volt and 1.0 volt. If voltage is as specified, go to next step. If voltage is not as specified, replace oxygen sensor.
3. Turn ignition switch to OFF position. Disconnect ECU connectors. Using an ohmmeter, check resistance between ECU connector B59, terminal No. 6 and sensor connector terminal No. 4 (White wire). Resistance should be zero ohms. Check resistance between sensor connector terminal No. 4 (White wire) and ground. Resistance should be one megohm or greater. If resistances are as specified, go to next step. If resistances are not as specified, repair appropriate circuit as necessary.
4. Disconnect main relay connector. Using an ohmmeter, check resistance between main relay connector terminal No. 1 (Black/White wire) and sensor connector terminal No. 1 (Black/White wire), and between main relay connector terminal No. 3 (White/Red wire) and sensor connector terminal No. 2 (White/Red wire). Resistance should be zero ohms for both circuits. If resistance is as specified, go to next step. If resistance is not as specified, repair appropriate circuit as necessary.
5. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and main relay connector terminals No. 2 (Brown/Black wire) and No. 4 (Yellow wire). Voltage should be 10 volts or greater at each terminal. If voltage is as specified, replace main relay. If voltage is not as specified, repair appropriate circuit as necessary.

CODE 33: VEHICLE SPEED SENSOR NO. 2

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Raise and support vehicle. Start engine and rotate wheels to check speedometer operation. If speedometer does not operate, go to next step. If speedometer operates, use a DVOM to check voltage between ECU connector B59, terminal No. 3 (backprobe) and ground. Voltage should toggle between zero and 5 volts. If voltage toggles as specified, go to next step. If voltage does not toggle as specified, go to step 5).
2. Turn ignition switch to OFF position. Disconnect ECU connectors. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and ECU connector B59, terminals No. 2 and 13.
3. Voltage should be 10 volts or greater at each terminal. If voltage is not as specified, repair appropriate circuit as necessary. If voltage is as specified, go to next step.
4. Turn ignition switch to OFF position. Using an ohmmeter, check resistance between ground and ECU connector B59, terminals No. 11 and 22. Resistance should be zero ohms at each terminal. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
5. Turn ignition switch to OFF position. Disconnect speed sensor connector. Using an ohmmeter, check resistance between ECU connector B60, terminal No. 11 and speed sensor connector terminal No. 1 (Yellow/Red wire). Resistance should be zero ohms. If resistance is as specified, go to next step. If resistance is not as specified, repair circuit as necessary.
6. Turn ignition switch to ON position. Using a DVOM, check voltage between speed sensor connector terminal No. 1 (Yellow/Red wire) and ground. Voltage should be 10 volts or greater. If voltage is as specified, go to next step. If voltage is not as specified, go to step 8).
7. Using a DVOM, check voltage between main relay connector terminal No. 3 (Green/Yellow wire) and ground. Voltage should be 10 volts or greater. If voltage is as specified, replace main relay. If voltage is not as specified, repair circuit as necessary.
8. Remove speed sensor. Connect sensor connector to speed sensor. Connect DVOM between speed sensor connector terminals No. 1 (Yellow/Red wire) and No. 3 (Green/Yellow wire). While rotating speed sensor shaft, ensure voltage switches from zero to 5 volts, 4 times per revolution. If voltage changes as described, speed sensor is okay. Malfunction is mechanical. If voltage does not change as described, replace speed sensor.

CODE 34: EXHAUST GAS RECIRCULATION (EGR) SOLENOID VALVE

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B62, terminal No. 14 (backprobe) and ground. Voltage should be 10 volts or greater. If voltage is not as specified, go to next step. If voltage is as specified, go to step 4).
2. Turn ignition switch to OFF position. Disconnect ECU and main relay connectors. Using an ohmmeter, check resistance between ECU connector B62, terminal No. 14 and main relay connector terminal No. 4 (Yellow wire). Resistance should be zero ohms. If resistance is as specified, go to next step. If resistance is not as specified, repair circuit as necessary.
3. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and main relay connector terminals No. 1 (Black/White wire) and 2 (Brown/Black wire). Voltage should be 10 volts or greater at both terminals. If voltage is as specified, replace main relay. If voltage is not as specified, repair appropriate circuit as necessary.
4. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B62, terminal No. 22 (backprobe) and ground. Voltage should be 7 volts or greater. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
5. Turn ignition switch to OFF position. Remove collector and disconnect EGR solenoid valve connector. Using an ohmmeter, check resistance between ECU connector B62, terminal No. 22 and EGR solenoid valve connector terminal No. 2 (White/Black wire). Resistance should be zero ohms. If resistance is as specified, replace EGR solenoid valve. If resistance is not as specified, repair circuit as necessary.

CODE 35: PURGE CONTROL SOLENOID VALVE

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B62, terminal No. 14 (backprobe) and ground. Voltage should be 10 volts or greater. If voltage is not as specified, go to next step. If voltage is as specified, go to step 4).
2. Turn ignition switch to OFF position. Disconnect ECU and main relay connectors. Using an ohmmeter, check resistance between ECU connector B62, terminal No. 14 and main relay connector terminal No. 4 (Yellow wire). Resistance should be zero ohms. If resistance is as specified, go to next step. If resistance is not as specified, repair circuit as necessary.
3. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and main relay connector terminals No. 1 (Black/White wire) and No. 2 (Brown/Black wire). Voltage should be 10 volts or greater at each terminal. If voltage is as specified, replace main relay. If voltage is not as specified, repair appropriate circuit as necessary.
4. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B62, terminal No. 6 (backprobe) and ground. Voltage should be 7 volts or greater. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
5. Turn ignition switch to OFF position. Remove collector and disconnect purge control solenoid valve connector. Using an ohmmeter, check resistance between ECU connector B62, terminal No. 6 and solenoid valve connector terminal No. 2 (White/Red wire). Resistance should be zero ohms. If resistance is as specified, replace purge control solenoid valve. If resistance is not as specified, repair circuit as necessary.

CODE 37: OXYGEN (O2) SENSOR NO. 2

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Warm engine to operating temperature and allow to idle. Using a DVOM, check voltage between ECU connector B61, terminal No. 5 (backprobe) and ground. Voltage should vary between 0.1 volt and 1.0 volt. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
2. With engine at idle, disconnect oxygen sensor connector, located on left side of engine. Using a DVOM, check voltage between sensor connector terminal No. 4 (Yellow/Blue wire) and ground. Voltage should vary between 0.1 volt and 1.0 volt. If voltage is as specified, go to next step. If voltage is not as specified, replace left oxygen sensor.
3. Turn ignition switch to OFF position. Disconnect ECU connectors. Using an ohmmeter, check resistance between ECU connector B59, terminal No. 5 and sensor connector terminal No. 4 (Yellow wire). Resistance should be zero ohms. Check resistance between sensor connector terminal No. 4 (Yellow wire) and ground. Resistance should be one megohm or greater. If resistances are as specified, go to next step. If resistances are not as specified, repair circuit as necessary.
4. Disconnect main relay connector. Using an ohmmeter, check resistance between main relay connector terminal No. 2 (Brown/Black wire) and sensor connector terminal No. 1 (Black/White wire), and between main relay connector terminal No. 4 (Yellow wire) and sensor connector terminal No. 2 (White/Red wire). Resistance should be zero ohms for both circuits. If resistance is as specified, go to next step. If resistance is not as specified, repair appropriate circuit as necessary.
5. Turn ignition switch to ON position. Using a DVOM, check voltage between ground and main relay connector terminals No. 2 (Brown/Black wire) and No. 4 (Yellow wire). Voltage should be 10 volts or greater. If voltage is as specified, replace main relay. If voltage is not as specified, repair appropriate circuit as necessary.

CODE 41: AIR/FUEL LEARNING CONTROL

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Check fuel injector operation and repair as necessary. See Codes 14, 15, 16, 17, 18 and 19. If injectors are okay, check airflow sensor (Code 23) and repair as necessary. If airflow sensor is okay, check coolant temperature sensor (Code 21) and repair as necessary. If coolant temperature sensor is okay, check throttle position sensor (Code 31) and repair as necessary. If throttle position sensor is okay, check both oxygen sensors (Codes 32 and 37) and repair as necessary. If oxygen sensors are okay, go to next step.
2. Check system fuel pressure. See BASIC TESTING article. Ensure all fuel injectors are operating properly. If all components have been inspected and Code 41 is still present, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.

CODE 45: ATMOSPHERIC PRESSURE SENSOR

A faulty atmospheric pressure sensor may cause erratic idle or engine will not start. Sensor is located inside ECU. If Code 45 is present, replace ECU.

CODE 51: NEUTRAL POSITION SIGNAL

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B60, terminal No. 10 (backprobe) and ground. With shifter in Neutral, voltage should be zero.
2. Check voltage at terminal No. 10 with shifter in all other positions. Voltage should be 8 volts or greater. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
3. Turn ignition switch to OFF position. Disconnect neutral switch connector located near transaxle dipstick. Using an ohmmeter, check resistance between neutral switch connector terminal No. 1 (Light Green/Yellow wire) and ground. With shifter in Neutral, resistance should be zero ohms.
4. Check resistance at terminal No. 1 with vehicle in all other shift positions. Resistance should be one megohm or greater. If resistances are not as specified, replace neutral switch. If resistances are as specified, repair circuit between ECU and neutral switch as necessary.

CODE 52: PARKING POSITION SIGNAL

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B60, terminal No. 9 (backprobe) and ground. With shifter in Park, voltage should be zero.
2. Check voltage at terminal No. 9 with vehicle in all other shift positions. Voltage should be 8 volts or greater. If voltages are not as specified, go to next step. If voltages are as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
3. Turn ignition switch to OFF position. Disconnect inhibitor switch connector located near transaxle dipstick. Using an ohmmeter, check resistance between inhibitor switch connector terminal No. 2 (Light Green wire) and ground. With shifter in Park, resistance should be zero ohms.
4. Check resistance at terminal No. 2 with shifter in all other positions. Resistance should be one megohm or greater. If resistances are not as specified, replace inhibitor switch. If resistances are as specified, repair circuit between ECU and inhibitor switch as necessary.

CODE 55: EXHAUST GAS RECIRCULATION (EGR) TEMPERATURE SENSOR

Note. Refer to illustration for ECU connector and terminal identification. (Scheme 8)

1. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B59, terminal No. 4 (backprobe) and ground. Voltage should be 4-4.8 volts at 68°F (20°C) and 0.4-1.2 volts at 212°F (100°C). If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
2. Turn ignition switch to OFF position. Disconnect EGR temperature sensor connector. Using an ohmmeter, backprobe ECU and check resistance between ECU connector B59, terminal No. 4 and temperature sensor connector terminal No. 2 (Green/White wire), and between ECU connector B59, terminal No. 11 and temperature sensor connector terminal No. 1 (Black/Red wire). Resistance should be zero ohms for both circuits.
3. Check resistance between sensor connector terminal No. 2(Green/White wire) and ground. Resistance should be one megohm or greater. If resistances are as specified, replace EGR temperature sensor. If resistances are not as specified, repair appropriate circuit as necessary.

CODE 56: EXHAUST GAS RECIRCULATION (EGR) SYSTEM

A faulty EGR system may cause poor driveability at low engine speed. Check for mechanical problem with EGR valve, faulty EGR vacuum controller and/or EGR line. Check for EGR valve stuck in open or closed position. For EGR system diagnosis, see I - SYS/COMP TESTS article.