Chery Tiggo. Manual — part 207
Idle Air Control (IAC) Motor
Description
The Idle Air Control (IAC) motor is mounted to the throttle body, and regulates the amount of air bypassing the con-
trol of the throttle valve. As engine loads and ambient temperatures change, engine RPM changes. A pintle on the
IAC motor protrudes into a passage in the throttle body, controlling air flow through the passage. The IAC motor is
control by the ECM to maintain the target engine idle speed.
Operation
At idle, engine speed can be increased by retracting the IAC motor pintle and allowing more air to pass through the
port, or it can be decreased by restricting the passage with the pintle and diminishing the amount of air bypassing the
throttle valve.
The IAC is called a stepper motor because it is moved in steps, or increments. Opening the IAC opens an air pas-
sage around the throttle valve with increases RPM.
Removal & Installation
1. Disconnect the negative battery cable.
2. Disconnect idle air control motor electrical connec-
tor from the wiring harness connector.
3. Remove the idle air control motor retaining bolts
(1).
(Tighten: Air control motor retaining bolt to 10 N·m)
4. Remove the idle air control motor.
5. Installation is in the reverse order of removal.
ON-VEHICLE SERVICE
LTSM030013
03
Crankshaft Position (CKP) Sensor
Description
The Crankshaft Position (CKP) sensor is located on the flywheel shell facing the gear teeth of the signal plate. It
detects the fluctuation of the engine revolution. The sensor consists of a permanent magnet and Induction coil.
Operation
When the engine is running, the high and low parts of the teeth cause the gap with the sensor to change. The
changing gap cause the magnetic field near the sensor to change. Due to the changing magnetic field, the voltage
from the sensor changes. The Engine Control Module (ECM) receives the voltage signal and detects the fluctuation
of the engine revolution.
Removal & Installation
1. Disconnect the negative battery cable.
2. Disconnect the crankshaft position sensor electrical
connector from the crankshaft position sensor.
3. Remove the accessory drive belt (See Accessory
Drive Belt Removal & Installation in Section 02
Engine).
4. Remove the crankshaft pulley (See Crankshaft Pul-
ley Removal & Installation in Section 02 Engine).
5. Remove the timing belt lower cover (See Timing
Belt Lower Cover Removal & Installation in Section
02 Engine).
6. Remove the crankshaft position sensor retaining
bolts (1).
(Tighten: Crankshaft position sensor retaining bolt
to 20 N·m)
7. Installation is in the order of removal.
ON-VEHICLE SERVICE
LTSM030012
2.4L ENGINE SYMPTOM DIAGNOSIS
Symptom Diagnostic Tests
03-544
General Troubleshooting Checks
03-544
Visual Inspection
03-544
Diagnostic Help
03-544
Symptom Diagnostic Test List
03-544
Engine Cranks Normal But Will Not
Start
03-545
Engine Will Not Crank
03-547
Hard Start / Long Crank / Erratic Start /
Erratic Crank
03-549
Fast Idle
03-552
Lack / Loss Of Power
03-553
Back Fires
03-556
Engine Poor Driveability
03-558
Low Idle / Stalls During Deceleration
03-562
Idle Speed Slow Return To Normal Idle
03-564
03
Symptom Diagnostic Tests
General Troubleshooting Checks
• Confirm the engine trouble light is working properly.
• Confirm that there are no DTCs recorded with the X-431 Scan Tool.
• Confirm that the customer’s complaint is current, and the conditions that are causing the failure are present.
Visual Inspection
• Check the fuel system for any fuel leakage.
• Check the vacuum system for any broken, kinked or incorrectly linked vacuum pipes or hoses.
• Check the intake air pipe for being jammed, leaking, or damaged.
• Check the ignition system for any broken or aging spark plug wires and verify the engine firing order is correct.
• Check the engine ground cable and verify a clean and tight connection.
• Check the sensors and actuators electrical connectors and verify good contact and tight connection.
NOTE :
Repair any of the above conditions first before continuing with symptom diagnostics.
Diagnostic Help
• Confirm there are no current engine DTCs.
• Confirm that the failure exists and the customer complaint can be verified.
• Inspect the engine following the above steps and verify all engine features are operating properly.
• While servicing the vehicle, verify the service record, vehicle maintenance, engine compression pressures,
mechanical ignition timing and fuel conditions.
• If replacing the Engine Control Module (ECM), carry out the validation test. If the failure no longer exists, the
failure is in the ECM; if the failure still exists, reinstall the original ECM and repeat the diagnostic test.
Symptom Diagnostic Test List
SYMPTOM DEFINITION
Engine Cranks Normal But Will Not Start
Engine Will Not Crank
Hard Start / Long Crank Time
Fast Idle
Lack / Loss Of Power
Back Fires
Engine Poor Driveability
Low Idle / Stalls During Deceleration
Idle Speed Slow Return To Normal Idle
ELECTRONIC ENGINE CONTROLS - 2.4L ENGINE SYMPTOM DIAGNOSIS
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