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Engine Controls - Tests W/codes - 2.0L: Other Nissan 200SX S14

Testing & Diagnostics 1 illustration ~1795 words

MALFUNCTION INDICATOR LIGHT

The Malfunction Indicator Light (MIL) is located on instrument panel and is labeled CHECK ENGINE. The MIL will illuminate if the ECM detects a failure of a OBD-II emission related component. When this occurs, a Diagnostic Trouble Code (DTC) will be set into ECM memory.

When a malfunction has been detected in 2 consecutive drive cycles, the ECM will turn on the MIL and store a DTC in memory. One exception is if a misfire malfunction is detected that may damage catalytic converter, the MIL will illuminate or flash immediately and DTC will be set. If the same malfunction is not detected for 3 consecutive drive cycles the ECM will turn MIL off. The DTC will remain in ECM memory for 40 drive cycles, if fault does not recur DTC will be purged from ECM memory.

If MIL remains on during engine cranking, it could indicate the ECM is not receiving CMP signal or the MIL circuit is shorted to ground. If MIL blinks there may be a severe misfire being detected by ECM. To turn MIL off after a repair, a ECM reset command from the scan tool must be sent, or 3 consecutive drive cycles must be completed without any detected malfunction. See DRIVE CYCLES . If MIL never illuminates, check MIL circuit for opens and shorts. See the WIRING DIAGRAMS article.

FREEZE FRAME DATA

When a DTC is stored, ECM will also record and store engine operating conditions when malfunction occurred. This information is referred to as freeze frame data. Freeze frame data will be stored in ECM memory until cleared, with the exception of the occurrence of an engine misfire or fuel trim malfunction. When a misfire of fuel trim fault occurs, freeze frame data will be updated with the most current information regarding these failures. Freeze frame data cannot be accessed using MIL.

Freeze frame data available is

  1. Engine coolant temperature.
  2. Engine speed.
  3. Vehicle speed.
  4. Long term fuel compensation (long term fuel trim - displayed as percent).
  5. Short term fuel compensation (short term fuel trim - displayed as percent).
  6. Fuel control condition
  7. Open or closed loop.
  8. Malfunction of rear O2S.
  9. Calculated load value (displayed as percent)
  10. Diagnostic Trouble Code (DTC) during data recording.

OXYGEN SENSOR MONITOR

  1. To check if the left front oxygen sensor is switching between rich and lean, activate diagnostic test mode 2. See procedures under «RETRIEVING CODES USING MIL»(ref-17820-S40669541162000122900000) under SELF-DIAGNOSTICS USING MIL. Start engine while in mode 2 and run until fully warm. Run engine at 2000 RPM without load for 2 minutes, while monitoring MIL.
  2. If MIL flashes at least 5 times every 10 seconds, this indicates front oxygen sensor is functioning and fuel mixture is switching between lean and rich. This is an indication fuel mixture control system is okay.
  3. If MIL stays lit all or most of the time, a lean condition is indicated. Mixture control may be in open loop, ensure engine is fully warm. Fuel mixture may be lean or oxygen sensor may be faulty. Check for DTCs and repair if necessary. Check for conditions that could cause lean mixture, if okay, replace oxygen sensor.
  4. If MIL is off all or most of the time, a rich condition is indicated. Check for DTCs and repair as necessary. Check for conditions that could cause a rich condition, if okay, replace oxygen sensor.
  5. To monitor right front oxygen sensor after monitoring left front oxygen sensor, turn diagnostic mode selector on ECM fully clockwise. Wait 2 seconds, then turn mode selector fully counterclockwise. MIL will quickly flash twice indicating change to right oxygen sensor monitoring. To switch back to left oxygen sensor monitoring repeat procedure. MIL will flash quickly 4 times.

EQUIPMENT HOOK-UP

Ensure scan tool is OBD-II compliant. Turn ignition off. Connect data cable to OBD-II data link connector (located under left side of instrument panel). Plug power cable into cigar lighter. Turn ignition on.

Pattern "A"

Drive cycle pattern "A" exercises the misfire and fuel system monitors. In drive cycle pattern "A", start engine and let idle (or drive vehicle) until engine coolant temperature reaches at least 158°F (70°F). Turn engine off.

Pattern "B"

In drive cycle pattern "B", EGR and fuel system components are monitored. With engine warm, start engine. Let idle briefly, then drive vehicle up to legal freeway speeds for several minutes. Return to idle and turn engine off.

Pattern "C"

Drive cycle pattern "C" monitors catalyst and other components. Using scan tool, check FREEZE FRAME DATA , for engine speed, engine temperature and calculated load data to recreate. Also for catalyst monitoring purposes, a steady cruise for at least 2 minutes should be achieved.

DATA MONITOR

Data monitor function allows viewing of ECM input and output signals in real time. Turn ignition off. Ensure scan tool is properly connected. Program scan tool using the following steps

  1. Select vehicle and engine selection menu (optional).
  2. Select year, engine, model and any additional information requested by scan tool (optional).
  3. Select GENERIC OBD-II OPTIONS.
  4. Select DATA MONITOR.
  5. Turn ignition on or start engine and allow to idle.
  6. Follow operating instructions from scan tool menu.
  7. Select input or output signal desired.

FINAL CHECK

  1. Ensure all electrical components and connectors hooked-up.
  2. Test drive vehicle under conditions that may recreate fault.
  3. Recheck for DTCs.

If symptom or DTC(s) return, ensure ECM terminals are not bent, corroded or damaged in any way. If no fault can be found and symptom or DTC remains, substitute a known-good ECM and retest.

Check Component

Ensure vacuum system hoses are routed correctly. Inspect EGRC-BPT valve and EGR system. See SYSTEM/COMPONENT TESTS - 2.0L article. Repair or replace as required and perform FINAL CHECK .

Check Input Signal Circuit

Turn ignition switch to OFF position. Disconnect ECM and A/T control unit harness connectors. Using an ohmmeter, check continuity between ECM harness connector terminal No. 7 and A/T control unit harness connector terminal No. 13 (Purple wire). If no continuity exists, repair open in Purple wire. If continuity exists, disconnect and reconnect harness connectors in circuit and perform FINAL CHECK .

Scheme 6

Scheme 6: DTC P1900 - COOLING FAN CIRCUIT
Scheme 6: DTC P1900 - COOLING FAN CIRCUIT
  1. Check Low Speed (A/T Models) And High Speed (M/T Models) Fan Operation Turn ignition switch to OFF position. Disconnect cooling fan relays No. 2 and 3. (Scheme 6) Start engine. Set temperature lever to full cold position. Turn A/C switch and blower fan switch to ON position. Run engine at idle for several minutes. Verify cooling fan operates at low speed for A/T models and high speed for M/T models. If fan does not operate as specified, go to step 4). If fan operates as specified, go to next step.
  2. Check High Speed Fan Operation (A/T Models) Turn ignition switch to OFF position. Reconnect cooling fan relays No. 2 and 3. Disconnect cooling fan relay No. 1. Turn ignition switch to ON position. Turn A/C switch and blower fan switch to OFF position. Disconnect Engine Coolant Temperature (ECT) sensor harness connector. Connect 150-ohm resistor across ECT sensor harness connector terminals. Restart engine. Verify cooling fan operates at high speed. If fan does not operate at high speed, go to step 6). If fan operates at high speed, check cooling system for leaks, radiator cap pressure and thermostat operation. Repair as necessary. Inspect ECT sensor. See the «SYSTEM/COMPONENT TESTS - 2.0L»(ref-17821) article. Replace as necessary.
  3. Check Ground Circuit Turn ignition switch to OFF position. Disconnect cooling fan motors No. 1 and 2 harness connectors. Using an ohmmeter, check continuity between fan motor No. 1 harness connector terminal No. 1 and fan relay No. 1 harness connector, terminal No. 5 (Green/Black wire). If no continuity exists, repair open in Green/Black wire. If continuity exists, check continuity between fan motor No. 2 harness connector terminal No. 1 and fan relay No. 1 harness connector, terminal No. 5 (Green/Black wire). If no continuity exists, repair open in Green/Black wire. If continuity exists, go to next step.
  4. Using an ohmmeter, check continuity between fan motor harness connector terminal No. 2 on M/T models (Black wire) and terminal No. 4 (Black wire) on A/T models and ground. If no continuity exists, repair open in Black wire. If continuity exists, go to next step.
  5. Check Power Supply Turn ignition switch to OFF position. Disconnect cooling fan relay No. 1. Turn ignition switch to ON position. Using a voltmeter, measure voltage between cooling fan relay No. 1 harness connector, terminal No. 1 (Brown wire) and ground. If battery voltage does not exist, check for blown fuse No. 21 or fault in Brown wire. Repair or replace as required. If battery voltage exists, measure voltage between cooling fan relay No. 1 harness connector, terminal No. 3 (Green wire) and ground. If battery voltage does not exist, check for burnt fusible link "e" or fault in Green wire. Repair or replace as required. If battery voltage exists, go to next step.
  6. Check Output Signal Circuit Disconnect ECM harness connector. see scheme 3 Using an ohmmeter, check continuity between ECM harness connector terminal No. 14 and cooling fan relay No. 1 harness connector, terminal No. 2 (Light Green/Red wire). If no continuity exists, repair open in Light Green/Red wire. If continuity exists, go to next step.
  7. Check Ground Circuits (High Speed) Turn ignition switch to OFF position. Disconnect cooling fan motor No. 1 and 2 harness connectors. Using an ohmmeter, check continuity between fan motor No. 1 harness connector terminal No. 2 and fan relay No. 2 harness connector, terminal No. 5 (Green/Yellow wire). If no continuity exists, repair open in Green/Yellow wire. If continuity exists, check continuity between fan motor No. 2 harness connector terminal No. 3 and fan relay No. 3 harness connector, terminal No. 5 (Light Green/Blue wire). If no continuity exists, repair open in Light Green/Blue wire. If continuity exists, go to next step.
  8. Check Output Signal Circuit (High Speed) Disconnect ECM harness connector. see scheme 3 Using an ohmmeter, check continuity between ECM harness connector terminal No. 13 and fan relay No. 2 harness connector, terminal No. 2 (Light Green wire). see scheme 4 If no continuity exists, repair open in Light Green wire. If continuity exists, check continuity between ECM harness connector terminal No. 14 and fan relay No. 1 harness connector, terminal No. 2 (Light Green/Red wire). If no continuity exists, repair open in Light Green/Red wire. If continuity exists, go to next step.
  9. Check Components Inspect cooling fan relay No. 1 and cooling fan motors No. 1 and 2. See the «SYSTEM/COMPONENT TESTS - 2.0L»(ref-17821) article. Replace relays and motors as required. Apply pressure to cooling system using tester. Pressure should not drop. Repair as required. Test radiator cap using cap tester. Replace as required. Inspect thermostat and ECT sensor. Disconnect and reconnect harness connectors in circuit and perform «FINAL CHECK»(ref-17820-S16658626442000122900000).

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