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Troubleshooting Tips

SERVICE POINTS / OUTLINE




Main Relay (Battery Power)
- If the circuit is open, the engine will not start.
- If the circuit is shorted, the Electronic Gasoline Injection (EGI) fuse (30A) will burn out.





Room Fuse (Powertrain Control Module Engine (PCME) Memory Power)
- If the circuit is open, the PCME memory function will not operate, and diagnostic trouble codes for intermittent malfunctions will not be indicated. Also, the learning control will be canceled, but will not produce any particular symptom.
- If the circuit is shorted, the ROOM fuse (15A) will burn out.





Ground (Output Devices, Injector)
- If either output device ground or an injector ground has an open circuit, no particular symptom will be produced. If the related output device and injector grounds both have open circuits, the engine will not start.

Ground (System, Analogue)
- An open circuit will not produce any particular symptom.





TEN Terminal (Data Link Connector)
- If the circuit is open, the Self-Diagnosis Checker can not perform a diagnostic trouble code check and switch monitoring check.
- If the circuit is shorted, the opening amount of the idle air control valve will not change, causing hard starting and rough idle. Also, the ignition timing will be fixed, causing lack of power and poor acceleration. The Self-Diagnosis Checker cannot perform sensor monitoring checks.





MEN Terminal (Data Link Connector)
- If the circuit is open, the Self-Diagnosis Checker monitor light will not illuminate.
- If the circuit is shorted, the Self-Diagnosis Checker monitor light will stay on.





FEN Terminal (Data Link Connector)
- If the circuit is open, the Self-Diagnosis Checker buzzer will not sound during the diagnostic trouble code check.
- If the circuit is shorted, code "88" will keep flashing and the buzzer will continue sounding, preventing a diagnostic trouble code check.





Malfunction Indicator Lamp (MIL)
- If the circuit is open, the MIL will not illuminate with the ignition switch ON.
- If the circuit is shorted, the MIL will not go off after the engine is started.


INPUT DEVICES




Volume Airflow Sensor (With Intake Air Temperature Sensor)
- If the temperature sensor (within the volume airflow sensor) or circuit has an open or short, Diagnostic Trouble Code No. 10 will be output, and the PCME uses a preprogrammed intake air temperature of 20°C 68°F).
- If the intake air temperature sensor system fails, no particular symptom will be noticed.
- If the Vs or Vc terminal of the volume airflow sensor has an open or short circuit, Diagnostic Trouble Code No. 08 will be output, and the throttle position sensor and idle switch signal will be used to adjust the basic injection amount as to the following three modes.
1. Idle switch ON.
2. Small throttle angle.
3. Large throttle angle









Crankshaft Position Sensor (Ne 1, Ne 2, G Signal)
- If the Ne 2 signal circuit has an open or short, Diagnostic Trouble Code No. 02 is output.
- If the Ne 1 signal circuit has an open or short, Diagnostic Trouble Code No. 04 is output.
- If the G signal circuit has an open or short, Diagnostic Trouble Code No. 03 is output.





Engine Coolant Temperature Sensor
- If the temperature sensor or circuit has an open or short, Diagnostic Trouble Code No. 09 is output, and the PCME will use a preprogrammed temperature value of 80°C (176°F}.
- A malfunction in the engine coolant temperature sensor system may cause rough idle, engine stalling, or hard starting.





Intake Air Temperature Sensor (Dynamic Chamber)
- If the temperature sensor (in the dynamic chamber) or circuit has an open or short, Diagnostic Trouble Code No. 11 is output, and the PCME will use a preprogrammed value of 20°C (68°F).
- If the intake air temperature sensor system fails, no particular symptom will be noticed.





Throttle Position Sensor
- If the Vref terminal or TVO terminal has an open or short circuit, Diagnostic Trouble Code No. 12 is output.
- If the IDL terminal (Idle switch) or ground has an open circuit, Diagnostic Trouble Code No. 12 may be output.
- In both of the above conditions, the PCME uses a throttle valve fully-open program.
- If the throttle position sensor is not properly adjusted or the throttle position sensor system fails, poor acceleration or shift shock will result.

Idle Switch
- The switch monitor function can confirm the presence of an open or short circuit.
- If the circuit is open, Diagnostic Trouble Code No. 12 may be output.
- If the circuit is open, rough idle or engine stalling may appear because of inoperative Idle Speed Control (ISC) control.
- If the circuit is shorted, fuel will be cut when the accelerator pedal is pressed, causing hunting.





Heated Oxygen Sensor
- If sensor output voltage is not generated (because of an open or short circuit), Diagnostic Trouble Code No. 15 (left bank sensor) and/or 23 (right bank sensor) is output.
- If the heated oxygen sensor output voltage continues unchanged 20 seconds after engine exceeds 1,500 rpm, Diagnostic Trouble Codes No.17 (left bank sensor) and/or 24 (right bank sensor) is output.
- In the above conditions, no closed loop control will be present and no symptoms will be noticed.





Knock Sensor
- If the knock sensor or circuit has an open or short, Diagnostic Trouble Code No. O5 (left bank) and/or 07 (right bank) is output.
- In the above conditions, ignition timing is retarded.





Exhaust Gas Recirculation (EGR) Function Sensor / EGR Control Valve
- If the EGR function sensor or circuit has an open or short, Diagnostic Trouble Code No. 16 is output.
- In the above conditions, the EGR control valve will be fully closed.





Starter Signal
- A lack of starter signal input will cause hard starting.





Steering Pressure Sensor
- An open or short circuit can cause a momentary drop in engine speed during steering.





Central Processing Unit (CPU)
- The switch monitor function can confirm the presence of an open or short circuit in the headlight switch, fog light switch or rear defroster switch.
- An open or short circuit in the CPU circuit can cause a momentary drop in engine speed when the headlights, fog lights, or rear defroster is turned ON.





Air Conditioning (A/C) Signal (A/C Amplifier)
- The switch monitor function can confirm the presence of an open or short circuit.
- If the circuit is open, the air conditioner will not operate.
- If the circuit is shorted, the air conditioner will constantly operate with the blower ON.





Blower Signal (A/C Amplifier)
- The switch monitor function can confirm the presence of an open or short circuit.
- If the circuit has an open or short, the blower fan speed may momentarily drop when in the 3rd or higher position.





Stoplight Switch
- The switch monitor function can confirm the presence of an open or short circuit.
- An open or short circuit will produce no particular symptom.





Vehicle Speed Signal (Speedometer)
- If the vehicle speed signal circuit has an open or short, Diagnostic Trouble Code No. O6 is output.
- If the circuit is open or short, solenoid valve (purge control) will not operate.





Park/Neutral Signal
- If the circuit is open, the engine speed will be slightly low in P and N ranges.
- If the circuit is shorted, the engine speed will be slightly high in R, D, S, and L ranges.





Reduce Torque Signal
- If a malfunction occurs in the reduce torque signal, the torque reduction control system is inhibited and line pressure will be high at shifting. Shift shock may be slightly strong.





Shift Solenoids A, B Powertrain Control Module Transmission (PCMT)
- An open or short circuit may cause shift shock.

OUTPUT DEVICES




Injector
- If the circuit is open, the injector will be inoperative, causing rough idle and misfiring.
- If the circuit is shorted, the injector will inject fuel constantly, causing rough idle and misfiring.





IGT Signal (Igniter)
- If no IGT signals are input into the igniter because of an open or short circuit, the engine will not start.





Idle Air Control Valve (Bypass Air Control (BAC) Valve)
- If the control valve or circuit has an open or short, Diagnostic Trouble Code No. 34 is output.
- If the circuit is open, the valve will be fully closed, causing rough idle, engine stalling, and acceleration hesitation when cold.
- If the circuit is shorted, the valve will be fully opened and the idle speed will be increased, causing hunting.





Fuel Pump Relay
- If the circuit is open, the engine will not start.
- If the circuit is shorted, the fuel pump will remain operating with ignition switch ON.





Purge Solenoid Valve
- If the solenoid valve or circuit has an open or short, Diagnostic Trouble Code No. 26 is output.
- If the circuit is open or short, the solenoid valve will not operate.
- A short circuit may cause an improper air/fuel ratio, causing rough idle and hard starting.





Variable Inertia Charging System (VICS) Solenoid Valve
- If the solenoid valve or circuit has an open or short, Diagnostic Trouble Code No. 41 is output.
- If the circuit is open, the solenoid valve will stay OFF and the shutter valve will stay closed, causing a power drop in the high-speed range.
- If the circuit is shorted, the solenoid valve will stay ON and the shutter valve will stay open, causing a power drop in the middle-speed ranges.








EGR Solenoid Valve (Vacuum Side)
- If the solenoid valve or circuit has an open or short, Diagnostic Trouble Code No. 28 is output.
- An open circuit will produce no particular symptom.
- If the circuit is shorted, the solenoid valve will be fully opened, causing engine stalling and hard starting.





EGR Solenoid Valve (Vent Side)
- If the solenoid valve or circuit has an open or short, Diagnostic Trouble Code No. 29 is output.
- An open or short circuit will produce no particular symptom.





Oxygen Sensor Heater
- If the heater or circuit has an open or short circuit, Diagnostic Trouble Codes No. 36 (right bank heater) and/or 37 (left bank heater) will be output.
- An open or short circuit will produce no particular symptom.





A/C Signal (A/C Relay)
- If the circuit is open, the air conditioner will not operate.
- If the circuit is shorted, the air conditioner will constantly operate with the blower ON.





Cold Start Injector (CSI) Relay
- If the relay or circuit has an open or short, Diagnostic Trouble Code No. 30 is output.
- An open circuit will produce no particular symptom.
- A short circuit will make the cold start injector inoperative, requiring a slightly longer cranking time when cold.





Barometric Absolute Pressure Signal - (PCMT)
- If the pressure sensor or circuit has an open or short, the line pressure will not be controlled, causing rough shifting at high altitudes.





A/C Signal (PCMT)
- If the A/C signal circuit has an open or short, Diagnostic Trouble Code No. 65 is output.
- An open circuit is detected as A/C ON, and the air conditioning will be in the ON mode in D range (NORMAL), and slip lockup will be prohibited.
- A short circuit is detected as A/C OFF, and the air conditioning will be in the OFF mode in D range (NORMAL).





Torque Reduced Signal
- If a malfunction occurs in the torque reduced signal, the torque reduction control system is inhibited and the line pressure characteristics will be high when shifting. Shift shock may be slightly strong.

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