Kia Carens. Manual — part 77

wire is heated to specific temperature differential above incoming air. Two wires inside the MAF Sensors are exposed
to a portion of the airflow entering the engine :
The ambient temperature wire or "cold wire" isn't heated so this wire is the temperature of the surrounding air and
serves as the reference temperature.
The hot wire is heated by the MAF to be a certain amount above the ambient air. As soon as air flows over the wire,
bothwires are cooled. The control circuits then apply more voltage to keep the hot wire at the original temperature
differential. This creates a voltage signal monitored by the ECM. The greater the air flow and wire cooling, the greater
the signal.

• Engine coolant temperature sensor

The Engine Coolant Temperature (ECT) Sensor provides an input voltage to the ECM relating to coolant temperature.
The ECM uses this input signal along with inputs from other sensors to determine injector pulse width and ignition
timing. As coolant temperature varies the ECT Sensor's resistance changes. The change in resistance results in a
different input voltage to the ECM. When the engine is cold, the ECM will operate in Open Loop cycle. It will demand
slightly richer air/fuel mixtures and higher idle speeds until normal temperatures are reached.

• Throttle position sensor

The Throttle Position (TP) Sensor is a variable resistor that provides the ECM with an input signal (voltage) that
represents throttle blade position. The sensor is connected to the throttle blade position. The sensor is connected to
the throttle blade shaft. As the position of the throttle blade changes, the resistance of the TP Sensor changes. The
ECM supplies a 5V reference voltage to the TP Sensor. The TP Sensor output voltage (input signal to the ECM)
represents the throttle blade position. This will usually vary from around 0.25V at minimum throttle opening, the
around 4.7V at wide open throttle.

• Crankshaft position sensor

The Crankshaft Position (CKP) Sensor is used to signal the ECM when a spark and/or fuel injection event required.
The output from this sensor, in conjunction with the Camshaft Position Sensor signal, is used to determine whether
spark or fuel is required in a particular cylinder. The engine will not start without a CKP Sensor signal to the ECM.
Refer to section EE-IG for more information.

• Camshaft position sensor

The Camshaft Position (CMP) Sensor works with the CKP Sensor to provide inputs to the ECM to establish and
maintain correct injector firing order. Refer to section EE-IG for more information.

• Knock sensor

The Knock Sensor is a feedback signal used to control of ignition timing. When knocking occurs, the Knock Sensor
sends the signal to the ECM. The ECM then retards the ignition timing to reduce or eliminate the knock.

• Intake air temperature sensor

This sensor measures the temperature of the intake air and converts its charge into a resistance through a thermister
similar to the ECT Sensor. By monitoring the IAT Sensor, the ECM detects the intake air temperature and use it as
one of the signals to control fuel injectors and ignition timing.

• HO2 (Oxygen) Sensor

Two heated O2 Sensors are used in the vehicle. The sensors produce voltages from 0 to 1 volt, depending upon the
oxygen content of the exhaust has in the exhaust manifold. When a large amount of oxygen is present (caused by a
lean air/fuel mixture), the sensors produce a low voltage. When there is a lesser amount (rich air/fuel mixture) the
sensors produce ahigher voltage. By monitoring the oxygen content and converting it to electrical voltage, the sensors
act as a rich-leanswitch.
Both HO2 Sensors are equipped with a heating element that keeps the sensors at proper operating temperature
during all modes of operation. Maintaining correct sensor temperature at all times allows the system to enter into
closed loop operation faster and allows the system to remain in closed loop during periods of extended idle.

• Front HO2 Sensor

The front (upstream) HO2 Sensor is located in the exhaust downpipe after the TWC and provides an input voltage to
the ECM. The input tells the ECM the oxygen content of the exhaust gas. The ECM uses this information to fine tune
the air/fuel ratio by adjusting injector pulse width.

• Rear HO2 sensor

The rear (downstream) HO2 Sensor is located near the outlet end of the catalytic convertor. The rear HO2 Sensor
input isused to detect catalytic convertor deterioration. As the convertor deteriorates, the input from the downstream
sensor begins to match the upstream sensor input except for a slight time delay.
By comparing the rear HO2 Sensor input to the input from the front sensor, the ECM catalytic convertor efficiency.

Symptom Diagnosis charts

Description : Further describes the symptom. Confirm that the chart addresses the actual symptom before beginning
troubleshooting.
Troubleshooting Hints : This describes the possible point of malfunction.

Step : This shows the order of troubleshooting. Proceed with troubleshooting as indicated.
Check : This describes an inspection to determine the malfunction of parts quickly.
Remedy : This recommends the appropriate action to take as a resuit (Yes/No) of the check.
DIAGNOSTIC SYMPTOM INDEX

NO.

TROUBLESHOOTING ITEM

DESCRIPTION

1

Will not crank or cranks slowly

Refer Engine Electrical System

2

Cranks normally but
will not start

No combustion

Engnie cranks at normal speed but shows only partial
combustion and will not continue to run

3

Partial combustion
Engine cold

Engine cranks at normal speed but shows only partial
combustion and will not continue to run

4

Partial combustion
sfter warm-up

Engine start normally when cold, but will not start after running
and hot soaked

5

Cranks normally but
hard to start

Always

Engine cranks at normal speed but requires excessive cranking
time before starting

6

When engine is cold

Same condition as No.5 after running and cold; restarts normally
after warm-up

7

After warm-up

Same condition as No.5 after running and hot soaked; starts
normally when cold

8

Rough idle
(Low idle
speed/engine stalls at
idle)

Always

Engine stalls or vibrates excessively at idle.

9

Before warm-up

Engine stalls or vibrates excessively at idle during warm-up

10

After warm-up

Engine runs normally at idle during warm-up but vibrates
excessively or stalls after warm-up

11

When A/C ON

Engine stalls or vibrates excessively at idle when A/C ON

12 Rough idle/engine stalls just after starting

Engine stalls or vibrates excessively only just after starting
(acceleration from idle)

13 High idle speed after warm-up

Idle speed excessive after warm-up

14 Idle moves up and down/idle hunting

Engine speeds up and down periodically at idle

15 Engine stalls on deceleration

Engine unexpectedly stops running while decelerating or after
deceleration

16 Engine stalls suddenly (intermittent)

Engine intermittently stops running

17 Stumbles/hesitates on acceleration

Flat spot occurs just after accelerator depressed or mid jerking
occurs during acceleration

18 Surges while cruising

Unexpected change in engine speed which is usually repetitive

19 Lack of power

Performance poor under load when throttle valve wide open
Maximum speed reduced

20 Poor acceleration

Performance poor while accelerating

21 Runs rough on deceleration/backfire

Engine runs rough while decelerating and abnormal combustion
occurs in exhaust system

22 Knocking

Abnormal combustion accompanied by audible "pinging" noise

23 Fuel odor

Gasoline odor in cabin

24 High oil consumption

Oil consumption excessive

25 MIL always ON

Kia Data Pro Scan Tool does not indicate Diagnostic Trouble
Code but MIL always ON

26 MIL never ON

Kia Data Pro Scan Tool indicates malfunction

27 A/C does not work

Blower fan operates but magnetic clutch does not operate

Driveaveability definitions

Stumble : Mild jerking during asseleration.
Hesitation : Delay in increase in engine speed occrring just after the asselerator pedal is depressed.
Surge : Continuous soft jerking during cruise.

Precautions for symptom diagnosis

Fuel system pressure release

THE FUEL SYSTEM TRMAINS UNDER PRESSURE WHEN THE ENGINE IS NOT RUNNING. RELEASE FUEL
SYSTEM PRESSURE BEFORE DISCONNECTINGANY FUEL LINE TO REDUCE THE CHANCE TO VEHICLE
COMPONENTS. FUEL IS EXPLOSIVE. AN EMPTY FUEL TANK CAN STILL CONTAIN EXPLOSIVE GASES.
SUPPLY ADEQUATE VENTIALTION TO THE WORK AREA. DO NOT SMOKE, AND KEEP SPARKS AND OPEN
FLAAES AWAY. REFER TO SECTION 22, FUEL SYSTEM FOR FUEL SYSTEM PRESSURE RELEASE
PROCEDURE.

Symptom related diagnostic procedure

Symptom diagnosis chart

2

Cranks normally, but will not start (no combustion)

Description

· Cranks normally, but no combustion
· Battery is OK
· Throttle valve closed while cranking

(Troubleshooting hint)
No fuel injection to engine because of fuel shortage or no ignition in all cylinders.
1. No spark
· Ignition control malfunction
· Malfunction of ignition system component
2. No fuel injection
· Malfunction of fuel pump
· Malfunction of injector

3. Low fuel line pressure
4. Low engine compression pressure

Step

Check

Action

1

Check strong blue spark at each spark plug
cord disconnected.
Is blue spark present?

Yes

Go to step 5.

No

Go to next step.

2

Check that malfunction indicator light is
illuminated while ignition switch is ON.
Does MIL stay on after engine start-up?

Yes

Malfunction indicator light is illuminated.
Check for causes. Refer to Troubleshooting
with diagnostic trouble codes, page 21-18.

No

Go to next step

3

Check ignition system. Check resistance of
DLI coils.
Primary : Approx. 0.45~0.55Ω
Secondary : 13 -15Ω
Check wiring harness between ECM and DLI
coil.
Is resistance within specification?

Yes

Go to next step.

No

Replace ignition coils or repair wiring harness.

4

Check high tension cords.
Resistance : 16kΩ/m
Check for damage to spark plug wires.
Are spark plug wires OK?

Yes

Go to next step.

No

Replace spark plug wires.

5

Connect data link connector terminals fuel
pump and B+ with a jumper wire and check
operational sound of fuel pump.
Does fuel pump operate?

Yes

Check that engine starts on this condition.
- Check fuel pump relay or wiring harness if
engine starts.
- Go to step 7 if engine does not start.

No

Go to next step.

6

Check that battery voltage is applied on
RED/BLK wire of fuel pump connector when
ignition switch is ON.

Yes

Check continuity of fuel pump (between
PNK/BLK and BLK).

No

Repair the related wiring harness.

7

Crank engine and check operational sound of
injector

Yes

Go to step 10.

No

Go to next step.

8

Check that battery voltage is applied on
injector connector when ignition switch is ON.

Yes

Go to next step.

No

Check wire between main relay and injector.

9

Check that the resistance of injector is 14.5Ω.

Yes

Go to next step.

No

Replace injector.

10

Connect the data link connector terminals
FUEL PUMP and B+ with a jumper wire and
check fuel line pressure while ignition switch is
ON.
Fuel line pressure : 46~51 psi (320~350 kPa,
3.2~3.5 kg/cm²)
Is fuel line pressure within specification?

Yes

Go to next step.

No

High pressure :
Disconnect return line from filter side.
Blow through line towards tank.
If line is clear, try with new pressure regulator.
If line is blocked, check for blockage in return
line and clean or replace as necessary.

Low pressure :
Block return line and check if pressure rises.
If pressure rises, replace pressure regulator.
If pressure does not rise, check fuel filter at
fuel delivery module.
If it is OK, measure fuel pump max.
Pressure and replace as necessary.

11

Check engine compression pressure.

Yes

Go to next step.