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Chery Tiggo. Manual - part 157

• Continuity should exist.

• Also check harness for short to power.

Is the check result normal?

Yes

Go to the next step.

Repair or replace the circuit for an open or short to power in harness or connectors.

CHECK FUEL PRESSURE

• Release fuel pressure to zero.

• Install fuel pressure gauge (2) and check fuel

pressure.

• Observe the following fuel pressures when testing (See Fuel Pressure Test in Section 04 Fuel Delivery)

FUEL PRESSURES

Key On

400 kPa (4 bar)

Key Off

380 kPa (3.8 bar) in 10 minutes

Engine Idle 400 kPa (4.0 bar) - 420 kPa (4.2 bar)

Is the check result normal?

Yes

Go to step 7.

Go to the next step.

DIAGNOSIS & TESTING

BESM030020

DETECT MALFUNCTIONING PART

• Check the following:

− Fuel pump and circuit
− Fuel pressure regulator

Is the check result normal?

Yes

Go to the next step.

Repair or replace malfunctioning part.

CHECK MAF SENSOR

• Turn ignition switch off.

• Install all removed parts.

• Check air flow in data stream.

MAF SENSOR SIGNAL

TERMINAL NO.

ITEM

CONDITION

DATA

Air flow sensor

• Engine is running

• ECT: 78°C

• Idle: 795 RPM

• IAT: 36°C

• IAT signal: 1.88 V

322 kg/h

1.39 V

Is the check result normal?

Yes

If with the X-431, go to the next step.
If without the X-431, go to step 9.

Check connectors for damaged or air flow signal circuit for short to power.

PERFORM ACTIVE TEST FUNCTION

• Start engine.

• Select ⬙ACTIVE TEST⬙ menu.

• Perform injector active test.

• Make sure that each test produces a momentary engine speed drop.

Is the check result normal?

Yes

Go to step 11.

Go to the next step.

CHECK FUNCTION OF INJECTOR

• Listen to each injector operating sound.

• Operating sound should exist.

Is the check result normal?

Yes

Go to step 11.

Go to the next step.

DIAGNOSIS & TESTING

10.

CHECK INJECTOR CONTROL CIRCUIT

• Turn ignition switch off.

• Disconnect injector harness connector (1).

• Disconnect ECM harness connector.

• check harness for short to ground between following terminals.

• Continuity should not exist.

INJECTOR NO.

ECM

TERMINAL

INJECTOR

TERMINAL

Is the check result normal?

Yes

Go to the next step.

Repair or replace the circuit for short to ground in harness or connectors.

11.

CHECK INJECTOR RESISTANCE

• Disconnect injector harness connectors (See Fuel Pressure Test in Section 04 Fuel Delivery).

• Check the fuel injector resistance as shown in the following:

INJECTOR RESISTANCE

INJECTOR

NO.

INJECTOR

TERMINAL

RESISTANCE

(APPROXIMATELY)

⍀ (20°C)

1 & 2

11 - 16

1 & 2

DIAGNOSIS & TESTING

BESM040006

Is the check result normal?

Yes

Go to the next step.

Replace injector.
Go to step 14.

12.

CHECK INJECTOR

WARNING!

Confirm that the engine is cooled down and there are no fire hazards near the vehicle.

• Remove fuel delivery rail with injectors (See Fuel Injector Rail Removal & Installation 1.6L/1.8L/2.0L in Section

04 Fuel Delivery).

NOTE :
Be careful not to drop the fuel injectors when removing the fuel delivery rail.
• Keep fuel hose and all injectors connected to injector rail.

• Disconnect all injector harness connectors.

• Disconnect all ignition coil harness connectors.

• Prepare pans or saucers under each injector.

• Crank engine for about 3 seconds.

• Make sure fuel does not drip from injector.

Is the check result normal?

Yes

Go to next step.

Replace any leaking injectors as necessary. Always replace the O-ring seal when replacing the fuel

injector .

13.

CHECK DTC

• With the X-431 scan tool, read ECM DTCs.

• Refer to ⬙DTC Confirmation Procedure⬙.

Is DTC P0172 still present?

Yes

Replace the ECM.

NOTE : The Immobilizer control module must be matched to the new ECM (See ECM Removal & Instal-

lation in Section 03 Electronic Engine Controls).

The system is now operating properly.
Reassemble the vehicle and road test to verify the customers complaint is repaired.

DIAGNOSIS & TESTING

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