Self Diagnostics
Here is the link for how to do a self-diagnostic on the Altima,
http://www.stac-consulting.com/serrano.j/altima/ecu/Reading_ECU_Codes.pdf
Other Nissan models have different modes. Such as,
Mode I - Exhaust Oxygen Sensor Monitor
Use Mode I to determine if the Oxygen Sensor is functioning properly.
1. Warm the engine to normal temperature.
2. Run the engine above 2000 RPM under no load while looking at the ECU.
3. Make sure the GREEN LED goes on and off more than five times during ten seconds at 2000 RPM.
If the number of flashes are not more than five, replace the oxygen sensor. If the LED does not flash, check the sensor's circuit.
Mode II - Mixture Ratio Control Monitor
Use Mode II to determine if the air/fuel mixture is cycling correctly.
1. Warm the engine to normal operating temperature.
2. Turn the dial on the ECU fully clockwise (or if you have a switch, turn it on).
3. After the LED flashes twice, turn the dial fully counter clockwise (or turn the switch off).
4. Run the engine above 2000 RPM under no load while looking at the ECU.
If the RED LED blinks simultaneously with the GREEN LED, the air/fuel mixture is cycling properly.
If the RED LED stays off, the mixture is more than 5% rich.
If the RED LED stays on, the mixture is more than 5% lean.
If the RED LED stays on or off above 2000 RPM, complete the diagnostics before beginning repairs.
Mode III - Stored Fault Code Reporting
Use Mode III to retrive all stored trouble codes in memory.
1. Turn the ignition switch on, but do not start the engine.
2. On the ECU, turn the diagnostic mode selector screw fully clockwise (or if you have a switch, turn it on). Wait until the LED flashes 3 quick bursts, then turn the screw fully counter clockwise (or turn the switch off).
3. The check engine light will begin to flash trouble codes. Red flashes are units of ten and green flashes are units of one. (red-3 flashes, green-1 flash = code 31) Note all codes until it begins to loop.
To clear all stored codes, turn the screw fully clockwise (or turn the switch on). Wait until the LED flashes 4 quick bursts, then turn the screw fully counter clockwise (or turn the switch off). To retain the codes in memory, simply turn the ignition off.
Diagnostic Troube Codes (DTC)
11 Crankshaft Angle Sensor/Camshaft Position Sensor (CAS/CPS)
12 Air Flow Meter/Mass Air Flow Sensor (MAF)
13 Engine Coolant Temperature Sensor (CTS)
14 Vehicle Speed Sensor (VSS)
21 Ignition Signal
22 Fuel Pump
23 Idle Switch
24 Throttle Valve Switch
25 Idle Speed Control Valve (ISCV)
28 Cooling Fan Circuit
31 Electronic Control Unit (ECU)
32 Exhaust Gas Recirculation (EGR)
33 Heated Oxygen Sensor (HO2S)
34 Knock Sensor (KS)
35 Exhaust Gas Temperature Sensor (EGT)
36 EGR Control-Back Pressure Transducer (EGRC-BPT)
37 Knock Sensor (KS)
38 Right hand bank Closed Loop (B2)
41 Intake Air Temperature Sensor (IAT)
42 Fuel Temperature Sensor (FTS)
43 Throttle Position Sensor (TPS)
45 Injector Leak
47 Crankshaft Position Sensor (CPS)
51 Injector Circuit
53 Oxygen Sensor (O2)
54 Automatic Transmission (A/T) Control
55 No Malfunction
63 No. 6 Cylinder Misfire
64 No. 5 Cylinder Misfire
65 No. 4 Cylinder Misfire
66 No. 3 Cylinder Misfire
67 No. 2 Cylinder Misfire
68 No. 1 Cylinder Misfire
71 Random Misfire
72 TWC Function right hand bank
73 TWC Function right hand bank
76 Fuel Injection System Function right hand bank
77 Rear Heated Oxygen Sensor Circuit
82 Crankshaft Position Sensor (CPS)
84 Automatic Transmission (A/T) Diagnosis Communication Line
85 VTC Solenoid Valve Circuit
86 Fuel Injection System Function right hand bank
87 Canister Control Solenoid Valve Circuit
91 Front Heated Oxygen Sensor Heater Circuit right hand bank
94 TCC Solenoid Valve
95 Crankshaft Position Sensor (CPS)
98 Engine Coolant Temperature Sensor (CTS)
101 Front Heated Oxygen Sensor Heater Circuit right hand bank
103 Park/Neutral Position Switch Circuit
105 EGR and EGR Canister Control Solenoid Valve Circuit
108 Canister Purge Control Valve Circuit
Mode IV - Switch Operation Monitor
Use Mode IV to determine if the Throttle Position Sensor (TPS), Starter circuit and/or Vehicle Speed Sensor (VSS) are in proper working order.
1. Turn the ignition switch on, but do not start the engine.
2. Turn the dial on the ECU fully clockwise. After the LED flashes 4 times, turn the dial fully counter clockwise.
3. Make sure the RED LED is turned off.
4. Make sure the RED LED turns on when depressing the gas pedal. If not, check or replace the Throttle Position Sensor.
5. Make sure the RED LED turns on when turning the ignition key the START position. If not, check or replace the starter.
Drive the vehicle with the ECU unbolted and within view. Make sure the GREEN LED turns on when speed is 12 MPH or more. If not, check or replace the Vehicle Speed Sensor.
Mode V - Real Time Diagnostic Function
Use Mode V to determine if the Crankshaft Position Sensor (CPS), Mass Air Flow Sensor (MAF) and/or Ignition signal are working properly.
1. Start engine.
2. Turn the dial on the ECU fully clockwise.
3. After the LED flashes 5 times, turn the dial fully counter clockwise.
4. Make sure LEDs do not flash for 5 minutes when racing or idling the engine.
If it flashes, count the number of flashes, turn engine off, and see the following 3 paragraphs.
Perform real-time diagnosis insepction and repair or replace malfunctioning part if present.
If LEDs do not flash for 5 minutes, turn engine off.
If the RED LED flashes 3 times for 1.5 seconds, check the Crankshaft Position Sensor. Check the harness continuity at CPS when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.
If the GREEN LED flashes twice-3 times for 0.5 seconds, check Mass Air Flow Sensor. Check the harness continuity at MAFS when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.
If the GREEN LED flashes 4 times for 0.2 seconds 3 times, check the ignition signal. Check the harness continuity when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.
Here is the link for how to do a self-diagnostic on the Altima,
http://www.stac-consulting.com/serrano.j/altima/ecu/Reading_ECU_Codes.pdf
Other Nissan models have different modes. Such as,
Mode I - Exhaust Oxygen Sensor Monitor
Use Mode I to determine if the Oxygen Sensor is functioning properly.
1. Warm the engine to normal temperature.
2. Run the engine above 2000 RPM under no load while looking at the ECU.
3. Make sure the GREEN LED goes on and off more than five times during ten seconds at 2000 RPM.
If the number of flashes are not more than five, replace the oxygen sensor. If the LED does not flash, check the sensor's circuit.
Mode II - Mixture Ratio Control Monitor
Use Mode II to determine if the air/fuel mixture is cycling correctly.
1. Warm the engine to normal operating temperature.
2. Turn the dial on the ECU fully clockwise (or if you have a switch, turn it on).
3. After the LED flashes twice, turn the dial fully counter clockwise (or turn the switch off).
4. Run the engine above 2000 RPM under no load while looking at the ECU.
If the RED LED blinks simultaneously with the GREEN LED, the air/fuel mixture is cycling properly.
If the RED LED stays off, the mixture is more than 5% rich.
If the RED LED stays on, the mixture is more than 5% lean.
If the RED LED stays on or off above 2000 RPM, complete the diagnostics before beginning repairs.
Mode III - Stored Fault Code Reporting
Use Mode III to retrive all stored trouble codes in memory.
1. Turn the ignition switch on, but do not start the engine.
2. On the ECU, turn the diagnostic mode selector screw fully clockwise (or if you have a switch, turn it on). Wait until the LED flashes 3 quick bursts, then turn the screw fully counter clockwise (or turn the switch off).
3. The check engine light will begin to flash trouble codes. Red flashes are units of ten and green flashes are units of one. (red-3 flashes, green-1 flash = code 31) Note all codes until it begins to loop.
To clear all stored codes, turn the screw fully clockwise (or turn the switch on). Wait until the LED flashes 4 quick bursts, then turn the screw fully counter clockwise (or turn the switch off). To retain the codes in memory, simply turn the ignition off.
Diagnostic Troube Codes (DTC)
11 Crankshaft Angle Sensor/Camshaft Position Sensor (CAS/CPS)
12 Air Flow Meter/Mass Air Flow Sensor (MAF)
13 Engine Coolant Temperature Sensor (CTS)
14 Vehicle Speed Sensor (VSS)
21 Ignition Signal
22 Fuel Pump
23 Idle Switch
24 Throttle Valve Switch
25 Idle Speed Control Valve (ISCV)
28 Cooling Fan Circuit
31 Electronic Control Unit (ECU)
32 Exhaust Gas Recirculation (EGR)
33 Heated Oxygen Sensor (HO2S)
34 Knock Sensor (KS)
35 Exhaust Gas Temperature Sensor (EGT)
36 EGR Control-Back Pressure Transducer (EGRC-BPT)
37 Knock Sensor (KS)
38 Right hand bank Closed Loop (B2)
41 Intake Air Temperature Sensor (IAT)
42 Fuel Temperature Sensor (FTS)
43 Throttle Position Sensor (TPS)
45 Injector Leak
47 Crankshaft Position Sensor (CPS)
51 Injector Circuit
53 Oxygen Sensor (O2)
54 Automatic Transmission (A/T) Control
55 No Malfunction
63 No. 6 Cylinder Misfire
64 No. 5 Cylinder Misfire
65 No. 4 Cylinder Misfire
66 No. 3 Cylinder Misfire
67 No. 2 Cylinder Misfire
68 No. 1 Cylinder Misfire
71 Random Misfire
72 TWC Function right hand bank
73 TWC Function right hand bank
76 Fuel Injection System Function right hand bank
77 Rear Heated Oxygen Sensor Circuit
82 Crankshaft Position Sensor (CPS)
84 Automatic Transmission (A/T) Diagnosis Communication Line
85 VTC Solenoid Valve Circuit
86 Fuel Injection System Function right hand bank
87 Canister Control Solenoid Valve Circuit
91 Front Heated Oxygen Sensor Heater Circuit right hand bank
94 TCC Solenoid Valve
95 Crankshaft Position Sensor (CPS)
98 Engine Coolant Temperature Sensor (CTS)
101 Front Heated Oxygen Sensor Heater Circuit right hand bank
103 Park/Neutral Position Switch Circuit
105 EGR and EGR Canister Control Solenoid Valve Circuit
108 Canister Purge Control Valve Circuit
Mode IV - Switch Operation Monitor
Use Mode IV to determine if the Throttle Position Sensor (TPS), Starter circuit and/or Vehicle Speed Sensor (VSS) are in proper working order.
1. Turn the ignition switch on, but do not start the engine.
2. Turn the dial on the ECU fully clockwise. After the LED flashes 4 times, turn the dial fully counter clockwise.
3. Make sure the RED LED is turned off.
4. Make sure the RED LED turns on when depressing the gas pedal. If not, check or replace the Throttle Position Sensor.
5. Make sure the RED LED turns on when turning the ignition key the START position. If not, check or replace the starter.
Drive the vehicle with the ECU unbolted and within view. Make sure the GREEN LED turns on when speed is 12 MPH or more. If not, check or replace the Vehicle Speed Sensor.
Mode V - Real Time Diagnostic Function
Use Mode V to determine if the Crankshaft Position Sensor (CPS), Mass Air Flow Sensor (MAF) and/or Ignition signal are working properly.
1. Start engine.
2. Turn the dial on the ECU fully clockwise.
3. After the LED flashes 5 times, turn the dial fully counter clockwise.
4. Make sure LEDs do not flash for 5 minutes when racing or idling the engine.
If it flashes, count the number of flashes, turn engine off, and see the following 3 paragraphs.
Perform real-time diagnosis insepction and repair or replace malfunctioning part if present.
If LEDs do not flash for 5 minutes, turn engine off.
If the RED LED flashes 3 times for 1.5 seconds, check the Crankshaft Position Sensor. Check the harness continuity at CPS when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.
If the GREEN LED flashes twice-3 times for 0.5 seconds, check Mass Air Flow Sensor. Check the harness continuity at MAFS when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.
If the GREEN LED flashes 4 times for 0.2 seconds 3 times, check the ignition signal. Check the harness continuity when the engine is stopped. Inspect the harness for dust and clean if necessary. Check the pin terminal at ECU for bends and remove them as necessary. Reconnect harness and recheck continuity. During real-time diagnosis, tap the harness connector or component and check if trouble code is displayed. If so, replace terminal.
