Troubleshooting

TROUBLESHOOTING BASICS

BASIC TROUBLESHOOTING GUIDE

CUSTOMER PROBLEM ANALYSIS SHEET

BASIC INSPECTION PROCEDURE: MEASURING RESISTANCE OF ELECTRONIC PARTS. Resistance measured at high temperature after driving may be high or low. Therefore, all resistance should be measured at room temperature (20 °C, 68°F) unless otherwise specified.INTERMITTENT PROBLEM INSPECTION PROCEDURE: Sometimes the most difficult part of troubleshooting is when a problem occurs but does not recur during testing. For example, the problem appears only when the vehicle is cold, not when it is hot. In this case, the technician must carefully read the Customer Problem Analysis Sheet and recreate (simulate) the environment and conditions in which the problem occurs.

1. 1
   Erase the Diagnostic Trouble Code (DTC).
2. 2
   Check the connector connection and inspect the terminals for poor connections, loose wires, deformed, broken or corroded terminals. Then check that the connectors are still connected correctly.

   

3. 3
   Gently shake the connector and wire harness in the vertical and horizontal directions.
4. 4
   Repair or replace the faulty component.
5. 5
   Perform a road test to confirm that the problem is resolved.

● VIBRATION SIMULATION

K.	Sensors and Actuators: Gently vibrate sensors, triggers or relays with your finger.

b.	Connectors and Wire Harness: Gently shake the connector and wire harness vertically, then horizontally.

● HEAT SIMULATION

K.	Heat the components suspected of causing the malfunction with a hair dryer or other heat source.

● WATER SPRAY SIMULATION

K.	Spray water on the vehicle to simulate rainy weather or conditions of extreme humidity.

● ELECTRICAL LOAD SIMULATION

K.	Activate all electrical systems to simulate a voltage surge (radio, fans, lights, rear window defroster, etc.).

CONNECTOR INSPECTION PROCEDURE

1. 1
   Handling the Connector

   K.	Never pull on the wire harness when disconnecting connectors.

   b.	When disconnecting a connector with a lock, press or pull the lock lever.

   vs.	Listen for a click when connectors are engaged. This sound indicates that they are locked correctly.

   d.	When using a test device to check circuit continuity or to measure voltage, always insert the probe from the wire harness side.

   e.	Check whether the connector terminals are waterproof from the connector side. Waterproof connectors cannot be accessed from the wire side.

2. 2
   Connector Checkpoint

   K.	When the connector is connected: Hold the connector and carefully check the connection and locking.

   b.	When the connector is disconnected: Check for a missing terminal, a crimped terminal or a broken wire strand by gently pulling on the wire harness. Visually check for rust, contamination, deformation and bending.

   vs.	Check the terminal tightening condition: Insert a spare male terminal into the female connector, then check the terminal tightening condition.

   d.	Gently pull on each individual wire to make sure that each wire is properly connected to the terminal.

3. 3
   Connector Terminal Repair

   K.	Clean the contact areas with compressed air and/or a rag.

   b.	If the contact pressure is abnormal, replace the female terminal.

4. 4
   Before removing the wire harness, check the position of the wire harness and the crimp to make sure it is secured properly.
5. 5
   Check the wire harness for twisting, tension or looseness.
6. 6
   Check for abnormally high temperature in the wire harness.
7. 7
   Check whether the wire harness rotates, moves or vibrates relative to the sharp edge of a part.
8. 8
   Check the connection between the wire harness and all installed components.
9. 9
   If the wire harness sheath is damaged, secure, repair or replace the wire harness.
10. 10
    Open Circuit Procedures

    • Continuity Check
    • VOLTAGE CHECK

    If an open circuit occurs (as shown in [FIG. 1]), it can be detected by Step 2 (continuity check method) or Step 3 (voltage check method), as shown below.

    

11. 11
    Continuity Check MethodSpecification (resistance) 1 Ω or less → Normal circuit; 1 MΩ or more → Open circuit

    K.

    Disconnect connectors (A) and (C) and measure the resistance between these two connectors, as shown in [FIG. 2]. In [FIG. 2], the measured resistance is more than 1 MΩ for wire 1 and less than 1 Ω for wire 2. Specifically, the open circuit is in wire 1. (Wire 2 is normal.) To locate the point correctly, check the sub-section of wire 1 as described in the following step.

    b.

    Disconnect connector (B) and measure the resistance between connectors (C) and (B1), and connectors (B2) and (A), as shown in [FIG. 3]. In this case, the resistance measured between connectors (C) and (B1) is more than 1 MΩ, and the open circuit is between terminal 1 of connector (C) and terminal 1 of connector (B1).

12. 12
    Voltage Check Method

    K.	For connectors that are still connected, measure the voltage between chassis ground and terminal 1 of connectors (A), (B) and (C), as shown in [FIG. 4]. The measured voltage at each connector is 5 V, 5 V and 0 V respectively. Therefore, the open circuit is between connectors (C) and (B).

13. 13
    Short-to-Ground Test Method

    • Continuity Check to Chassis Ground

    In case of a short to ground [FIG. 5], the failure point can be detected by performing Step 2 (chassis ground continuity check method), as shown below.

    

14. 14
    Continuity Check Method (with Chassis Ground)Specification (resistance) 1 Ω or less → Short to ground; 1 MΩ or more → Normal circuit

    K.

    Disconnect connectors (A) and (C) and measure the resistance between connector (A) and chassis ground, as shown in [FIG. 6]. The measured resistance is less than 1 Ω for wire 1 and more than 1 MΩ for wire 2. Specifically, wire 1 is shorted to ground. (Wire 2 is normal.) To locate the fault point correctly, check the sub-section of wire 1 as described in the following step.

    b.

    Disconnect connector (B) and measure the resistance between connector (A) and chassis ground, and between (B1) and chassis ground, as shown in [FIG. 7]. The resistance measured between connector (B1) and chassis ground is 1 Ω or less. The short to ground is between terminal 1 of connector (C) and terminal 1 of connector (B1).

WIRE HARNESS INSPECTION PROCEDURE. ELECTRICAL CIRCUIT INSPECTION ORDER: ● OPEN CIRCUIT CHECK ● SHORT CIRCUIT CHECK ● Voltage Drop Test: This test checks the voltage drop across a wire or connection or switch.

Q.	Connect the positive lead of the voltmeter to the wire end near the battery (or on the connector or switch side).

B.	Connect the negative jumper lead to the other end of the wire (or the other side of the connector or switch).

vs.	Run the circuit.

D.	The voltmeter shows the voltage difference between two points. A difference or drop of more than 0.1 volt (50 mV in a 5 V circuit) may indicate a problem. Check the circuit for poor or dirty connections.

SYMPTOM TROUBLESHOOTING CHART

MAIN SYMPTOM	DIAGNOSTIC PROCEDURE	ALSO CHECK
Engine Will Not Start (Engine Does Not Crank)	1 Check the battery. (Refer to Engine Electrical System - "Battery".) 2 Test the starter. (Refer to Engine Electrical System - "Starter".) 3 Clutch Start Switch (TM)
Cannot Start (Incomplete combustion)	1 Check the battery. (Refer to Engine Electrical System - "Battery".) 2 Check the fuel pressure. (Refer to Fuel System - "Repair Procedures".) 3 Check the ignition circuit. (Refer to Engine Electrical System - "Ignition System".) 4 Troubleshoot the immobilizer system. (Refer to Body Electrical System - "Immobilizer System") (If the immobilizer indicator is flashing)	diagnostic trouble codes Low compression Intake air leaks Timing belt has slipped or broken Contaminated Fuel
Hard Starting	1 Check the battery. (Refer to Engine Electrical System - "Battery".) 2 Check the fuel pressure. (Refer to Fuel System - "Repair Procedures".) 3 Check the ECT sensor and circuit (check DTC) 4 Check the ignition circuit. (Refer to Engine Electrical System - "Ignition System".)	diagnostic trouble codes Low compression Intake air leaks Contaminated Fuel Weak ignition spark
Poor Idle (Rough, unstable, or incorrect idle speed)	1 Check the fuel pressure. (Refer to Fuel System - "Repair Procedures".) 2 Check the injector. (Refer to Engine Control System - "Injector".) 3 Check the long-term and short-term fuel trim. (Refer to Customer Data Flow.) 4 Check the idle air control circuit. (Check the diagnostic trouble code.) 5 Inspect and clean the throttle body. 6 Check the ECT sensor and circuit (check DTC)	diagnostic trouble codes Low compression Intake air leaks Contaminated Fuel Weak ignition spark
ENGINE STALLS	1 Check the battery. (Refer to Engine Electrical System - "Battery".) 2 Check the fuel pressure. (Refer to Fuel System - "Fuel Pressure Test".) 3 Check the idle air control circuit. (Check the diagnostic trouble code.) 4 Check the ignition circuit. (Refer to Engine Electrical System - "Ignition System".) 5 Check the CKPS circuit. (Check the DTC.)	diagnostic trouble codes Intake air leaks Contaminated Fuel Weak ignition spark
Poor Driving (Imbalance)	1 Check the fuel pressure. (Refer to Fuel System - "Fuel Pressure Test".) 2 Inspect and clean the throttle body. 3 Check the ignition circuit. (Refer to Engine Electrical System - "Ignition System".) 4 Check the ECT sensor and circuit (check DTC) 5 Check the exhaust system for blockage. (Refer to Engine Mechanical System - "Exhaust Manifold".) 6 Monitor the long-term and short-term fuel trim. (Refer to Customer Data Flow.)	diagnostic trouble codes Low compression Intake air leaks Contaminated Fuel Weak ignition spark
Knock	1 Check the fuel pressure. (Refer to Fuel System - "Repair Procedures".) 2 Check the coolant. (Refer to Engine Mechanical System - "Radiator".) 3 Check the radiator and the electric cooling fan system. (Refer to Engine Mechanical System - "Radiator".) 4 Check the spark plugs. (Refer to Engine Electrical System - "Ignition System".)	diagnostic trouble codes Contaminated Fuel
Poor Fuel Economy	1 Check the customer's driving style. Is the air conditioner or defrost mode operating continuously? Is the tire pressure correct? Is the vehicle carrying an excessively heavy load? Is acceleration too strong or too frequent? 2 Check the fuel pressure. (Refer to Fuel System - "Repair Procedures".) 3 Check the injector. (Refer to Engine Control System - "Injector".) 4 Check the exhaust system for blockage. 5 Check the ECT sensor and circuit	diagnostic trouble codes Low compression Intake air leaks Contaminated Fuel Weak ignition spark
Difficult Refueling (Fuel overflow during refueling)	1 Check the fuel line/hose. Is it crushed, kinked, or blocked? Is the supply hose broken? 2 Check the fuel tank vapor vent hose located between the evaporative canister and the air cleaner. 3 Check the fuel vapor canister.	Malfunctioning fuel nozzle at the service station (if this problem occurs at a specific station during refueling).