Basic Inspection Procedure: Measuring Resistance of Electronic Parts. Resistance measured at high temperature after vehicle operation may be high or low. Therefore, all resistances must be measured at ambient temperature (20 °C, 68°F), unless otherwise specified.
Resistance measured at a temperature other than ambient temperature (20 °C, 68°F) is for reference only.
Intermittent Problem Inspection Procedure: Sometimes the most difficult case in troubleshooting is when the problem symptom occurs but does not recur during testing. For example, if the problem occurs only when the vehicle is cold and did not appear when warm. In this case, the technician must carefully complete the Customer Problem Analysis Check Sheet and recreate (simulate) the environment and conditions present when the vehicle problem occurred.
Clear the Diagnostic Trouble Code (DTC).
Inspect the connector connection and check the terminal for poor contact. Check for loose connections, loose wires, bent, broken or corroded pins, then check that the connectors are always securely fastened.
Gently shake the connector and wire harness vertically and horizontally.
Repair or replace the faulty component.
Confirm that the problem is resolved by performing a road test.
? Vibration Simulation
a.
Sensors and Actuators: Gently tap the sensors, actuators or relays with a finger.
Strong vibration may damage sensors, actuators or relays.
b.
Connectors and Harness: Gently shake the connector and wire harness vertically, then horizontally.
? Heat Simulation
a.
Heat the components suspected of causing the malfunction using a hair dryer or other heat source.
DO NOT heat the components to the point where they may be damaged.
DO NOT heat the ECM directly.
? Water Spray Simulation
a.
Spray water on the vehicle to simulate rainy or high humidity conditions.
DO NOT spray water directly into the engine compartment or onto electrical components.
? Electrical Load Simulation
a.
Turn on all electrical systems to simulate excessive electrical loads (radio, fans, lights, rear window defogger, etc.).
Connector Inspection Procedure
Connector Handling
a.
Never pull on the wire harness when disconnecting connectors.
b.
When disconnecting a connector with a lock, press or pull the locking lever.
b.
Listen for a click when connectors lock. This sound indicates that they are securely locked.
d.
When using a tester to check continuity or measure voltage, always insert the tester probe from the wire harness side.
e.
Check waterproof connector terminals from the connector side. Waterproof connectors cannot be accessed from the wire harness side.
Use a thin wire to avoid damaging the terminal.
Do not damage the terminal when inserting the tester wire.
Connector Checkpoints
a.
With the connector connected: While holding the connector, check the connection condition and locking efficiency.
b.
With the connector disconnected: Gently pull the harness and check for a missing terminal, crimped terminal or broken wire. Visually check for rust, contamination, deformation and bending.
b.
Check terminal tightness: Insert a spare male terminal into the female terminal, then check the terminal tightness condition.
d.
Gently pull on each individual wire to confirm that each wire is secured in the terminal.
Connector Terminal Repair Method
a.
Clean the contact points using compressed air and/or a cloth.
Never use sandpaper to polish contact points, as this may damage the contact point.
b.
If contact pressure is abnormal, replace the female terminal.
Before removing the wire harness, check the position and clamping of the wire harness to restore it correctly.
Check that the wire harness is not twisted, stretched or loose.
Check that the wire harness is not exposed to excessive temperature.
Check that the wire harness does not rotate, move or vibrate against sharp edges of components.
Check the connection between the wire harness and any installed part.
If the wire harness covering is damaged, secure, repair or replace the harness.
Open Circuit Procedures
Continuity Check
Voltage Check
If an open circuit occurs (as shown in [FIG. 1]), it can be located by performing Step 2 (Continuity Check Method) or Step 3 (Voltage Check Method), as shown below.
Continuity Check Method
When measuring resistance, gently move the harness up and down or left and right.
Specification (resistance) 1 Ω or less > Normal circuit; 1 MΩ or more > Open circuit
a.
Disconnect connectors (A) and (C) and measure the resistance between connectors (A) and (C), as shown in [FIG. 2]. In [FIG. 2], the measured resistance of lines 1 and 2 is above 1 MΩ and below 1 Ω respectively. Specifically, the open circuit is on line 1 (line 2 is normal). To find the exact break point, check the sections of line 1 as described in the following step.
b.
Disconnect connector (B) and measure the resistance between connectors (C) and (B1) and between (B2) and (A), as shown in [FIG. 3]. In this case, the measured resistance between connectors (C) and (B1) is above 1 MΩ, and the open circuit is between terminal 1 of connector (C) and terminal 1 of connector (B1).
Voltage Check Method
a.
With each connector still connected, measure the voltage between chassis ground and terminal 1 of each connector (A), (B) and (C), as shown in [FIG. 4]. The measured voltages of each connector are 5 V, 5 V and 0 V respectively. Therefore, the open circuit is between connectors (C) and (B).
Short to Ground Check Method
Continuity Check with Chassis Ground
If a short to ground occurs, as shown in [FIG. 5], the breakpoint can be located by performing Step 2 (Continuity Check Method with chassis ground), as shown below.
Continuity Check Method (with Chassis Ground)
Gently shake the harness up and down or left and right when measuring resistance.
Specification (resistance) 1 Ω or less > Short to ground; 1 MΩ or more > Normal circuit
a.
Disconnect connectors (A) and (C), and measure the resistance between connector (A) and chassis ground, as shown in [FIG. 6]. In this example, the measured resistance of lines 1 and 2 is below 1 Ω and above 1 MΩ respectively. Specifically, line 1 is shorted to ground (line 2 is normal). To find the exact break point, check the sub-line of line 1 as described in the next 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 measured resistance 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).
Harness Inspection Procedure Electrical Circuit Inspection Procedure ? Check for open circuit ? Check for short circuit ? Voltage drop test This test checks the voltage drop across a wire, connection or switch.
A.
Connect the positive voltmeter lead to the wire end (or connector or switch side) closest to the battery.
B.
Connect the negative lead to the other end of the wire (or the other side of the connector or switch).
C.
Operate the circuit.
D.
The voltmeter will show the voltage difference between the two points. A difference or drop of more than 0.1 V (50 mV in a 5 V circuit) may indicate a problem. Check the circuit for loose or dirty connections.
?
Test yourself
A quick Kia Soul EV Owner's Manual quiz: every answer comes with an explanation and a link to the manual page.
