Chery Tiggo 5 (T21). Manual - part 70

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06

DTC Confirmation Procedure

Confirm that battery voltage is over 12 V before performing the following procedures.
 Turn ignition switch to LOCK.
 Connect X-431 3G diagnostic tester (the latest software) to Data Link Connector (DLC).
 Turn ignition switch to ON.
 Use X-431 3G diagnostic tester to record and clear the DTCs stored in the ECM.
 Start the engine and warm it up to normal operating temperature, and then select Read Code.
 If the DTC is detected, the malfunction indicated by the DTC is current. Go to the diagnosis 

procedure - Step 1.

 If DTC is not detected, the malfunction indicated by the DTC is intermittent (

See page 06-18

).

Diagnosis Procedure

a. Connect X-431 3G diagnostic tester to Data Link Connector (DLC).
b. Turn ignition switch to ON. Start the engine and warm it up to normal operating temperature, and then 

select Read Code.

DTC

P0420-00 Catalyst System, Bank1 Efficiency Below Threshold

DTC Code

DTC Definitions

DTC Detection 

Conditions

Possible Cause

P0420-00

Catalyst System, 
Bank1 Efficiency 
Below Threshold

Engine running

 Three-way catalytic converter
 Leakage in exhaust system
 Upstream oxygen sensor 
 Downstream oxygen sensor 
 ECM

1

Check for any other DTCs output (in addition to DTC P0420-00)

Display (DTC Output)

Proceed to

DTC P0420-00

A

DTC P0420-00 and other DTCs

B

Go to DTC chart, and perform 
troubleshooting for other DTCs first

B

A

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a. Read datastream using diagnostic tester.
b. Check datastream below.

a. Turn ignition switch to ON and start the engine.
b. Check exhaust system for leakage.

2

Read datastream

Item

OK (Idling)

If it is NG, proceed to

Upstream Oxygen Sensor Voltage

Quickly fluctuates between 0.1 to 

0.9 V

A

Downstream Oxygen Sensor 

Voltage

Fluctuates slightly at about 0.45 V

B

Average Injection Pulse Width

1.5 - 2.9 ms

C

Replace upstream oxygen sensor

A

Check injector, fuel pressure and other 
causes for abnormal injection pulse width

3

Check exhaust system

C

B

Repair or replace related exhaust system 
components

NG

4

Check downstream oxygen sensor

OK

Replace downstream oxygen sensor

NG

Replace three-way catalytic converter, and go to step 5

OK

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a. Use X-431 3G diagnostic tester to read the ECM DTC.
b. Refer to "DTC Confirmation Procedure".
c. Check if DTC P0420-00 still exists.

5

Check for DTCs

Replace ECM

NG

System is operating normally.
Reassemble vehicle and perform a road test to confirm that malfunction reported by customer has 
been repaired.

OK

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SQR484F ENGINE MANAGEMENT SYSTEM

DTC

P0444-00

Evaporative Emiss. System Purge Control Valve Circ. 
Open

DTC

P0458-00

Evaporative Emission System Purge Control Valve 
Circuit Low

DTC

P0459-00

Evaporative Emission System Purge Control Valve 
Circuit High