Engine Controls - Self-Diagnostics - 2.4L (K24DE) & 3.3L (VG33E): Other Nissan Frontier D22

FREEZE-FRAME DATA

Note. 1st trip freeze-frame data values can only be displayed with Nissan's CONSULT, and are not displayed on generic scan tool.

ECM records operating conditions such as fuel system status, calculated load value, engine coolant temperature, short term fuel trim, long term fuel trim, engine speed, vehicle speed and absolute pressure. Freeze-frame data is a "snapshot" of these operating conditions present when a fault is detected. When a fault is detected for the first time, ECM stores the first trip DTC, along with first trip freeze-frame data. Only one set of freeze-frame data can be stored in ECM (either first trip freeze-frame data or freeze-frame data). There is no priority for first trip freeze frame data. It is updated each time a different first trip DTC is stored. If a fault is detected for the second time, first trip freeze-frame data is replaced with freeze-frame data.

Freeze-frame data is updated in order of priority. See FREEZE FRAME PRIORITY IDENTIFICATION table. If a priority 1 fault (misfire or fuel injection system malfunction) is detected in another trip when priority 2 freeze-frame data is already stored in ECM, priority 2 freeze-frame data will be replaced by priority 1 freeze-frame data.

Note. Only one 1st trip DTC and one freeze-frame data "snapshot" can be stored in ECM. If using a generic scan tool, 1st trip DTC freeze-frame information may not be accessible. Use CONSULT-II to retrieve 1st trip DTC freeze-frame information.

FREEZE FRAME PRIORITY IDENTIFICATION

Using CONSULT-II

1. If ignition is on, turn ignition off and wait at least 10 seconds. Turn ignition on. If DTC is A/T related, go to next step. If DTC is not A/T related, go to step 3 .
2. Turn CONSULT-II on and press A/T. Press SELF-DIAG RESULTS. Press ERASE. DTC in TCM is now cleared. Press BACK twice.
3. Press ENGINE. Press SELF-DIAG RESULTS. Press ERASE. DTC in ECM is now cleared.

FAIL-SAFE MODES

ECM enters a fail-safe mode if certain malfunctions are detected due to an open or short circuit. When ECM enters fail-safe mode, MIL illuminates. Refer to all diagnostic tests that apply for description and testing of circuit affected.

ECM (DTCs Not Accessible)

Maximum engine speed is 3000 RPM. Fuel injection operates in simultaneous mode. Ignition timing is fixed. Fuel pump relay remains on when engine is running and off when engine stalls. Idle Air Control Valve-Auxiliary Air Control (IACV-AAC) valve is fully open. If ECM fail-safe mode is confirmed, replace ECM.

Checking SRT Code Status (Using CONSULT-II)

Select SRT STATUS in DTC CONFIRMATION mode with CONSULT-II. For items whose SRT codes are set, CMPLT is displayed. For items whose SRT codes are not set, INCMP is displayed.

Setting SRT Codes (Using CONSULT-II)

Perform DTC CONFIRMATION TEST under corresponding DTC test under DIAGNOSTIC TESTS. If more than on SRT item needs to be set, perform DTC confirmation tests in order of priority. See SRT PRIORITY table.

SRT PRIORITY

Work Support Mode

This mode can be used for the following functions

1. FUEL PRESSURE RELEASE Use to release fuel pressure. Fuel pump will stop by touching START during engine idling. Crank a few times after engine stalls.
2. IDLE AIR VOL LEARN Use to perform idle air volume learning.
3. SELF-LEARNING CONT Use to clear the coefficient of self-learning control value. Air/fuel mixture ratio returns to the original coefficient.
4. EVAP SYSTEM CLOSE Use when testing EVAP system for leaks. This will open vacuum cut valve by-pass valve and close EVAP canister vent control valve in order to seal EVAP system under the following conditions: Ignition switch on. Engine not running. Ambient temperature is above 32°F (0°C). No vacuum and no high pressure in EVAP system. Fuel tank temperature is more than 32°F (0°C). Within 10 minutes after starting EVAP SYSTEM CLOSE. When trying to execute EVAP SYSTEM CLOSE when above conditions are not met, CONSULT-II will discontinue it and display appropriate instruction. NOTE: When starting engine, CONSULT-II may display BATTERY VOLTAGE IS LOW. Charge battery, even if using charged battery.
5. TARGET IDLE RPM ADJ Use when setting target idle speed. This function is usually unnecessary.
6. TARGET IGNITION TIMING ADJ Use when adjusting target ignition timing. After adjustment, verify target ignition timing with a timing light. This function is usually unnecessary.

Self-Diagnostic Results Mode

For DTC and 1st trip DTC descriptions, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . Freeze frame data and 1st trip freeze frame data show a snapshot of the following items at the moment a malfunction is detected.

1. FUEL SYS-B1 Or FUEL SYS-B2 Fuel injection system status for bank 1 or bank 2. One of the following modes is displayed: MODE 2: Open loop due to detected system malfunction. MODE 3: Open loop due to driving conditions (power enrichment, deceleration enrichment). MODE 4: Closed loop - using oxygen sensor(s) as feedback for fuel control. MODE 5: Open loop - has not yet satisfied condition to go into closed loop.
2. CAL/LD VALUE [%] Calculated load value.
3. COOLANT TEMP [°C] or [°F] Engine coolant temperature.
4. S-FUEL TRIM-B1 Or S-FUEL TRIM-B2 [%] Short-term fuel trim (indicates dynamic or instantaneous feedback compensation to base fuel schedule) for bank 1 or bank 2.
5. L-FUEL TRIM-B1 Or L-FUEL TRIM-B2 [%] Long-term fuel trim (indicates much more gradual feedback compensation to the base fuel schedule than short-term fuel trim).
6. ENGINE SPEED [rpm] Engine speed.
7. VHCL SPEED [km/h] or [mph] Vehicle speed.
8. B/FUEL SCHDL [msec] Base fuel schedule.
9. INT/A TEMP SE [°C] or [°F] Intake air temperature.

Data Monitor Mode

For DATA MONITOR mode descriptions, see DATA MONITOR MODE DESCRIPTIONS table.

DATA MONITOR MODE DESCRIPTIONS

Data Monitor (SPEC) Mode

For DATA MONITOR (SPEC) mode descriptions, see DATA MONITOR (SPEC) MODE DESCRIPTIONS table.

DATA MONITOR (SPEC) MODE DESCRIPTIONS

Mode 2: Freeze Frame Data

This mode gains access to emission-related data value information stored by ECM during the freeze frame portion of self-diagnostic mode during engine operation.

Mode 4: Clearing Codes

This mode can clear all emission related diagnostic information for DTCs. These include

1. Clear number of DTCs (MODE 1).
2. Clear DTCs (MODE 3).
3. Clear DTC for freeze-frame data (MODE 1).
4. Clear freeze-frame data (MODE 2).
5. Reset status of system monitoring test (MODE 1).
6. Clear on-board monitoring results (MODE 6 and 7).

Mode 6: On-Board Tests

This mode accesses the results of on-board diagnostic monitoring tests of specific components and systems that are not continuously monitored.

Mode 7: On-Board Tests

This mode enables the off-board test drive to obtain test results for emission-related powertrain components and systems that are continuously monitored during normal driving conditions.

NISSAN VEHICLE IMMOBILIZER SYSTEM

Nissan Vehicle Immobilizer System (NVIS) must be initialized after Engine Control Module (ECM) has been replaced. See appropriate IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT.

SUMMARY

If no diagnostic trouble code is present but driveability problem still exists, proceed to TROUBLE SHOOTING - NO CODES article for symptom diagnostic or intermittent diagnosis procedures.

FUSE BLOCK

Fuse block is located under left side of instrument panel. To identify components on fuse block (Scheme 178)

Scheme 178

Scheme 179

Scheme 180

Scheme 181

Scheme 182

Scheme 183

Scheme 184

Scheme 185

Scheme 186

Possible Causes

Malfunction is detected when

1. DTC P0103 An excessively high voltage from MAF sensor is sent to ECM when engine is not running.
2. DTC P0102 An excessively low voltage from MAF sensor is sent to ECM when engine is running.
3. DTC P0101 A high voltage from MAF sensor is sent to ECM under light load driving condition.
4. DTC P0101 A low voltage from MAF sensor is sent to ECM under heavy load driving condition.

Possible causes are

1. MAF sensor circuit open or shorted.
2. Defective MAF sensor.
3. Intake air leaks (malfunction "B" and "D" only).

Fail-Safe Mode

When malfunction "B" is detected, ECM enters fail-safe mode and MIL will illuminate. Engine speed will not rise more than 2400 RPM due to fuel cut.

Possible Cause

Malfunction is detected when an excessively low or high voltage from AP sensor is sent to the microcomputer. Possible cause is; faulty ECM.

Malfunction is detected when

1. DTC P0112 Or DTC P0113 An excessively low or high voltage from IAT sensor is sent to ECM.
2. DTC P0127 Rationally incorrect voltage from IAT sensor is sent to ECM, compared with voltage signal from ECT sensor.

Possible causes are

1. IAT sensor circuit open or shorted.
2. Defective IAT sensor.

Malfunction is detected when an excessively low or high voltage from ECT sensor is sent to ECM. Possible causes are

1. ECT sensor circuit open or shorted.
2. Defective ECT sensor.

When this malfunction is detected, ECM enters fail safe mode. MIL illuminates and ECM determines that ECT is fixed at 104°F (40°C) when ignition is first turned on, then increases based on engine run time. After 4 minutes, ECM determines that ECT is fixed at 176°F (80°C). Cooling fan operates while engine is running.

Malfunction is detected when

1. DTC P0122 Or DTC P0123 An excessively low or high voltage from TP sensor is sent to ECM.
2. DTC P0121 A high voltage from TP sensor is sent to ECM under light load driving condition.
3. DTC P0121 A low voltage from TP sensor is sent to ECM under heavy load driving condition.

Possible causes are

1. TP sensor circuit open or shorted.
2. Defective TP sensor.
3. Defective fuel injector (malfunction "B" only).
4. Defective camshaft position sensor (malfunction "B" only).
5. Defective mass airflow sensor (malfunction "B" only).
6. Intake air leaks (malfunction "C" only).

When malfunction "A" is detected, ECM enters fail-safe mode and MIL illuminates. ECM will determine throttle position based on injected fuel amount and engine speed. Therefore, acceleration will be poor.

Note. Perform the following DTC confirmation tests in order. If a DTC confirmation test has been previously performed, turn ignition off and wait at least 5 seconds before performing next DTC confirmation test.

Malfunction is detected when voltage sent to ECM from ECT sensor is not practical, even when some time has passed since starting engine. Or, engine coolant temperature is insufficient for closed loop fuel control. Possible causes are

1. ECT sensor circuit open or shorted.
2. Defective ECT sensor.
3. Defective thermostat.

Malfunction is detected when engine coolant temperature has not risen enough to open thermostat even though engine has run long enough. Possible causes are

1. Thermostat stuck open.
2. Leakage from sealing portion of thermostat.
3. Defective ECT sensor.

Malfunction is detected when an excessively high voltage from HO2S1 is sent to ECM. Possible causes are

1. HO2S1 circuit open or shorted.
2. Defective HO2S1.

Malfunction is detected when HO2S1 response time is too long. Possible causes are

1. HO2S1 circuit open or shorted.
2. Defective HO2S1.
3. Defective HO2S1 heater.
4. Fuel pressure incorrect.
5. Defective injectors.
6. Intake air leaks.
7. Exhaust leaks.
8. Defective PCV valve.
9. Defective Mass Airflow (MAF) sensor.

Note. Before proceeding, ensure ambient temperature is more than 14°F (-10°C) and battery voltage is more than 11 volts at idle.

Malfunction is detected when the voltage from HO2S1 is constantly about .3 volt. Possible causes are

1. HO2S1 signal circuit open or shorted.
2. Defective HO2S1.

Note. Before proceeding, ensure battery voltage is more than 11 volts at idle.

Malfunction is detected when an excessively high voltage from HO2S2 is sent to ECM. Possible causes are

1. HO2S2 circuit open or shorted.
2. Defective HO2S2.

Malfunction is detected when HO2S2 response time is too long. Possible causes are

1. HO2S2 circuit open or shorted.
2. Defective HO2S2.
3. Fuel pressure.
4. Injectors.
5. Intake air leaks.

Malfunction is detected when mixture ratio compensation amount is too large (mixture is too lean or too rich). Possible causes are

1. Defective HO2S1.
2. Defective injectors.
3. Exhaust leaks.
4. Fuel pressure incorrect.
5. Defective Mass Airflow (MAF) sensor.
6. Lack of fuel (DTCs P0171 or P0174 only).
7. Intake air leaks (DTCs P0171 or P0174 only).
8. Incorrect PCV hose connection (DTCs P0171 or P0174 only).

DTC P0181 will set when a rationally incorrect voltage from FTT sensor is sent to ECM, compared with voltage signals from engine coolant temperature sensor and intake air temperature sensor. DTC P0182 will set when an excessively low voltage from FTT sensor is sent to ECM. DTC P0183 will set when an excessively high voltage from FTT sensor is sent to ECM. Possible causes are

1. FTT sensor circuit open or shorted.
2. Defective FTT sensor.

Malfunction is detected when engine coolant temperature is excessively high under normal engine speed. Possible causes are

1. Defective cooling fan.
2. Defective thermostat.
3. Improper ignition timing.
4. Defective Engine Coolant Temperature (ECT) sensor.
5. Blocked radiator.
6. Blocked front end.
7. Improper mixture ratio of coolant.
8. Damaged bumper.

Malfunction is detected when one cylinder misfires or multiple cylinders misfire. Possible causes are

1. Improper spark plug.
2. Insufficient compression.
3. Incorrect fuel pressure.
4. Injector circuit is open or shorted.
5. Defective fuel injectors.
6. Intake air leak.
7. Ignition secondary circuit is open or shorted.
8. Lack of fuel.
9. Defective drive plate or flywheel.
10. Defective front HO2S.
11. Incorrect distributor rotor.

Malfunction is detected when ECM receives an excessively low or high voltage from knock sensor. Possible causes are

1. Knock sensor circuit open or shorted.
2. Defective knock sensor.

Malfunction is detected when proper pulse signal from CKP sensor is not sent to ECM while engine is running. Possible causes are

1. CKP sensor circuit open.
2. Defective CKP sensor.
3. Dead battery.

Malfunction is detected when

1. Either CMP sensor signal is not sent to ECM for the first few seconds during engine cranking.
2. Either CMP sensor signal is not sent to ECM often enough when engine is running at a specified speed.
3. Relation between 2 CMP sensor signals is not in the normal range when engine is running at a specified speed.

Possible causes are

1. CMP sensor circuit is open or shorted.
2. Defective CMP sensor.
3. Defective starter motor.
4. Faulty starting system circuit.
5. Dead (weak) battery.

Note. Perform the following DTC confirmation tests in order. If a DTC confirmation test has been previously performed, turn ignition off and wait at least 5 seconds before performing next DTC confirmation test.

Note. Before proceeding, ensure battery voltage is more than 10.5 volts at idle.

Malfunction is detected when no EGR flow is detected under conditions that call for EGR. Possible causes are

1. EGR valve stuck closed.
2. EGR Control Backpressure Transducer (EGRC-BPT) valve.
3. Vacuum hose.
4. EGRC solenoid valve.
5. EGR passage.
6. EGR temperature sensor.
7. Exhaust gas leaks.

Note. For best results, perform DTC confirmation test when ambient temperature is more than 41°F (5°C).

Malfunction is detected when EGRC-BPT valve does not operate properly. Possible causes are

1. Defective EGRC-BPT valve.
2. Defective EGR valve.
3. Backpressure hose blockage or leak.
4. Defective Camshaft Position (CMP) sensor.
5. Plugged exhaust.
6. Missing orifice in hose between EGRC-BPT valve and EGRC solenoid valve.
7. Defective Mass Airflow (MAF) sensor.
8. Defective EGRC solenoid valve.

Note. Before proceeding, ensure ambient temperature is more than 41°F (5°C) and battery voltage is more than 11 volts at idle.

Malfunction is detected when

1. DTC P0405 An excessively low voltage from EGR temperature sensor is sent to ECM even when engine coolant temperature is low.
2. DTC P0406 An excessively high voltage from EGR temperature sensor is sent to ECM even when engine coolant temperature is high.

Possible causes are

1. EGR temperature sensor circuit open or shorted.
2. Defective EGR temperature sensor.
3. Malfunction of EGR function, EGRC-BPT valve or EGRC solenoid valve.

Note. Perform the following DTC confirmation tests in order. If a DTC confirmation test has been previously performed, turn ignition off and wait at least 5 seconds before performing next DTC confirmation test.

Malfunction is detected when switching frequency of HO2S2 increases to a specified value, indicating that 3-way catalyst is not operating properly. Possible causes are

1. Defective 3-way catalyst.
2. Exhaust leak.
3. Intake air leaks.
4. Defective injectors.
5. Defective spark plugs.
6. Incorrect ignition timing.

Malfunction is detected when EVAP control system does not operate properly, or there is a leak between intake manifold and EVAP-CSPS. Possible causes are

1. EVAP-CPVCSV stuck closed.
2. Faulty EVAP-CSPS or circuit.
3. Loose, disconnected or improper connection of hoses.
4. Blockage in hoses.
5. Blocked hose to MAP/BARO switch solenoid valve.
6. Cracked EVAP canister.
7. Faulty EVAP-CPVCSV circuit.
8. Defective closed Throttle Position (TP) switch.
9. Blocked purge port.
10. Defective EVAP Canister Vent Control Valve (EVAP-CVCV).

Note. Before proceeding, ensure ambient temperature is 41°F (5°C) or more and battery voltage is more than 11 volts at idle.

Malfunction is detected when EVAP control system has a leak or does not operate properly. Possible causes are

1. Fuel filler cap remains open or fails to close.
2. Incorrect fuel tank vacuum relief valve.
3. Incorrect fuel filler cap.
4. Foreign matter in fuel filler cap.
5. Leak in hose between intake manifold and EVAP-CPVCSV.
6. Foreign matter in EVAP-CVCV.
7. Leak in EVAP canister or fuel tank.
8. Leak or blockage in EVAP purge line.
9. Leak or blockage in hose to EVAP Control System Pressure Sensor (EVAP-CSPS).
10. Defective EVAP-CVCV or circuit.
11. Defective EVAP-CPVCSV or circuit.
12. Defective absolute pressure sensor (2.4L).
13. Defective fuel tank temperature sensor.
14. Missing or damaged EVAP-CVCV "O" ring.
15. Defective EVAP-CSPS.
16. Defective fuel level sensor or circuit.
17. EVAP canister saturated with water.
18. Defective water separator.
19. Defective refueling control valve.
20. Leak in On-Board Refueling Vapor Recovery (ORVR) system.

Malfunction is detected when an excessively low or high voltage is sent to ECM through EVAP-CPVCSV. Possible causes are

1. EVAP-CPVCSV circuit open or shorted.
2. Defective EVAP-CPVCSV.

Malfunction is detected when improper voltage is sent to ECM through EVAP-CVCV. Possible causes are

1. EVAP-CVCV circuit open or shorted.
2. Defective EVAP-CVCV.

Malfunction is detected when an excessively low voltage is sent to ECM from EVAP-CSPS. Possible causes are

1. EVAP-CSPS circuit open or shorted.
2. EVAP-CSPS hose clogged, kinked, leaking, disconnected or improperly connected.
3. Defective EVAP-CSPS.
4. Defective EVAP Canister Vent Control Valve (EVAP-CVCV).
5. Defective EVAP Canister Purge Volume Control Solenoid Valve (EVAP-CPVCSV).
6. Defective EVAP canister.
7. Defective hose between EVAP-CVCV and water separator.

Note. Before proceeding, ensure ambient temperature is more than 41°F (5°C).

Malfunction is detected when EVAP control system has a very large leak, or EVAP control system does not operate properly. Possible causes are

1. Fuel filler cap remains open or fails to close.
2. Incorrect fuel tank vacuum relief valve.
3. Incorrect fuel filler cap.
4. Foreign matter caught in fuel filler cap.
5. Leak in line between intake manifold and EVAP-CPVCSV.
6. Foreign matter caught in EVAP Canister Vent Control Valve (EVAP-CVCV).
7. EVAP canister or fuel tank leaks.
8. Leak or blockage in EVAP purge line.
9. Blockage in EVAP Control System Pressure Sensor (EVAP-CSPS) hose.
10. Defective EVAP-CVCV or circuit.
11. Defective EVAP-CPVCSV or circuit.
12. Defective Absolute Pressure (AP) sensor (2.4L).
13. Defective Fuel Tank Temperature (FTT) sensor.
14. EVAP-CVCV "O" ring missing or damaged.
15. Defective EVAP-CSPS.
16. Defective refueling control valve.
17. Leak in On-Board Refueling Vapor Recovery (ORVR) system.

Malfunction is detected when EVAP control system has a very small leak or does not operate properly. Possible causes are

1. Incorrect fuel tank vacuum relief valve.
2. Incorrect fuel filler cap.
3. Fuel filler cap remains open or fails to close.
4. Foreign matter in fuel filler cap.
5. Leak in hose between intake manifold and EVAP Canister Purge Volume Control Solenoid Valve (EVAP-CPVCSV).
6. Foreign matter in EVAP Canister Vent Control Valve (EVAP-CVCV).
7. Leak in EVAP canister or fuel tank.
8. Leak or blockage in EVAP purge line.
9. Leak or blockage in hose to EVAP Control System Pressure Sensor (EVAP-CSPS).
10. Defective EVAP-CVCV or circuit.
11. Defective EVAP-CPVCSV or circuit.
12. Defective absolute pressure sensor (3.3L).
13. Defective fuel tank temperature sensor.
14. Missing or damaged EVAP-CVCV "O" ring.
15. Defective EVAP-CSPS.
16. Defective fuel level sensor or circuit.
17. EVAP canister saturated with water.
18. Defective water separator.
19. Defective refueling control valve.
20. Leak in On-Board Refueling Vapor Recovery (ORVR) system.

Malfunction is detected when ECM receives a varied signal from fuel level sensor while vehicle is parked. Possible causes are

1. Fuel level sensor circuit open or shorted.
2. Defective fuel level sensor.

Malfunction is detected when the output signal of the fuel level sensor does not change within the specified range even though the vehicle has been driven a long distance. Possible causes are

1. Fuel level sensor circuit open or shorted.
2. Defective fuel level sensor.

Malfunction is detected when ECM receives an excessively low or high voltage from fuel level sensor. Possible causes are

1. Fuel level sensor circuit open or shorted.
2. Defective fuel level sensor.

Malfunction is detected when zero MPH signal is sent to ECM even when vehicle is being driven. Possible causes are

1. VSS signal circuit open or shorted.
2. Defective VSS.

Malfunction is detected when IACV-AAC valve does not operate properly. Possible causes are

1. Defective IACV-AAC valve.
2. IACV-AAC valve circuit open (malfunction "A").
3. IACV-AAC valve circuit shorted (malfunction "B").

Note. Perform the following DTC confirmation tests in order. If a DTC confirmation test has been previously performed, turn ignition off and wait at least 5 seconds before performing next DTC confirmation test.

Malfunction is detected when battery voltage from closed TP switch is sent to ECM with throttle valve opened. Possible causes are

1. Closed TP switch circuit open or shorted.
2. Defective closed TP switch.
3. Defective TP sensor.

Malfunction is detected when ECM receives incorrect voltage from TCM. Possible cause is; circuit between ECM and TCM is open or shorted.

Malfunction is detected when ECM calculation function is malfunctioning. Possible cause is; faulty ECM.

Malfunction is detected when the maximum and minimum voltage from the sensor are not reached to the specified voltages. Possible causes are

1. Defective HO2S1.
2. Defective HO2S1 heater.
3. Fuel pressure incorrect.
4. Defective injectors.
5. Intake air leaks.

Note. Before proceeding, ensure ambient temperature is more than 14°F (-10°C) and battery voltage is more than 11 volts at idle.

Malfunction is detected when the maximum and minimum voltage from the sensor are beyond the specified voltages. Possible causes are

1. Defective HO2S1.
2. Defective HO2S1 heater.
3. Fuel pressure incorrect.
4. Defective injectors.

Note. Before proceeding, ensure ambient temperature is more than 14°F (-10°C) and battery voltage is more than 11 volts at idle.

Malfunction is detected when the minimum voltage from the sensor is not low enough. Possible causes are

1. HO2S2 circuit open or shorted.
2. Defective HO2S2.
3. Fuel pressure incorrect.
4. Defective injectors.

Malfunction is detected when the minimum voltage from the sensor is not low enough. Possible causes are

1. HO2S2 circuit open or shorted.
2. Defective HO2S2.
3. Fuel pressure incorrect.
4. Defective injectors.
5. Intake air leaks.

Malfunction is detected when fuel injection system does not operate in closed loop. Possible causes are

1. HO2S1 circuit open or shorted.
2. Defective HO2S1.
3. Defective front HO2S1 heater.

Note. Before proceeding, ensure battery voltage is more than 11 volts at idle.

Malfunction is detected when engine coolant reaches an abnormally high temperature. Possible causes are

1. Defective cooling fan.
2. Defective radiator hose.
3. Defective radiator.
4. Defective radiator cap.
5. Defective water pump.
6. Defective thermostat.

Malfunction is detected when chipping of flywheel or drive plate teeth is detected by ECM. Possible causes are

1. CKP sensor circuit open or shorted.
2. Defective CKP sensor.
3. Defective drive plate or flywheel.

Malfunction is detected when an improper voltage signal is sent to ECM through EGRC solenoid valve. Possible causes are

1. EGRC solenoid valve circuit open or shorted.
2. Defective EGRC solenoid valve.

Malfunction is detected when EGR flow is detected under conditions that do not call for EGR. Possible causes are

1. EGRC solenoid valve.
2. EGR valve leaking or stuck open.
3. EGR temperature sensor.
4. EGRC Backpressure Transducer (BPT) valve.

Malfunction is detected when EVAP control system has a leak or does not operate properly. Possible causes are

1. Incorrect fuel tank vacuum relief valve.
2. Incorrect fuel filler cap.
3. Fuel filler cap open or leaking.
4. Foreign matter in fuel filler cap.
5. Leak in hose between intake manifold and EVAP-CPVCSV.
6. Foreign matter in EVAP-CVCV.
7. Leak in EVAP canister or fuel tank.
8. Leak or blockage in EVAP purge line.
9. Leak or blockage in hose to EVAP-CSPS.
10. Defective EVAP-CVCV or circuit.
11. Defective EVAP-CPVCSV or circuit.
12. Defective Fuel Tank Temperature (FTT) sensor or circuit.
13. EVAP-CVCV "O" ring missing or damaged.
14. Defective water separator.
15. EVAP canister saturated with water.
16. Defective EVAP-CSPS.
17. Defective fuel level sensor or circuit.
18. Defective refueling control valve.
19. Leak in On Board Refueling Vapor Recovery (ORVR) system.
20. Foreign matter caught in EVAP-CPVCSV.

Malfunction is detected when canister purge flow is detected when EVAP-CPVCSV is closed. Possible causes are

1. Defective EVAP Control System Pressure Sensor (EVAP-CSPS).
2. EVAP-CPVCSV stuck open.
3. Defective EVAP Canister Vent Control Valve (EVAP-CVCV).
4. Defective EVAP canister.
5. EVAP system hoses misrouted or plugged.

Note. Before proceeding, ensure ambient temperature is more than 41°F (5°C).

Malfunction is detected when EVAP-CVCV remains closed under certain driving conditions. Possible causes are

1. Defective EVAP-CVCV.
2. Faulty EVAP Control System Pressure Sensor (EVAP-CSPS) or circuit.
3. Blockage in hose to EVAP-CVCV.
4. Defective water separator.
5. EVAP canister saturated with water.

Malfunction is detected when EVAP-CVCV remains open under certain driving conditions. Possible causes are

1. Defective EVAP-CVCV.
2. Faulty EVAP Control System Pressure Sensor (EVAP-CSPS) or circuit.
3. Blockage in EVAP-CVCV hose.
4. Defective water separator.
5. EVAP canister saturated with water.
6. Defective vacuum cut valve.

Malfunction is detected when ECM receives a high voltage from fuel level sensor. Possible cause is; fuel level sensor circuit open or shorted..

Malfunction is detected when ECM receives an improper voltage signal from vacuum cut valve by-pass valve. Possible causes are

1. Vacuum cut valve by-pass valve circuit open or shorted.
2. Defective vacuum cut valve by-pass valve.

Malfunction is detected when vacuum cut valve by-pass valve does not operate properly. Possible causes are

1. Defective vacuum cut valve by-pass valve.
2. Defective vacuum cut valve.
3. Blockage in by-pass hoses.
4. Fault in EVAP Control System Pressure Sensor (EVAP-CSPS) or circuit.
5. Defective EVAP Canister Vent Control Valve (EVAP-CVCV).
6. Blockage in hose between fuel tank and vacuum cut valve.
7. Blockage in hose between EVAP canister and vacuum cut valve.
8. Defective EVAP canister.
9. Blockage in fuel tank purge port.

Malfunction is detected when an incorrect signal from TCM is sent to ECM. Possible causes are

1. Communication circuit open or shorted.
2. Weak battery.
3. TCM.

Malfunction is detected when PNP switch signal does not change between starting and driving. Possible causes are

1. PNP switch circuit open or shorted.
2. Defective PNP switch.