ENGINE (DIAGNOSTICS)(H4DOTC DIESEL) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)
DTC DETECTING CONDITION:
Detected when two consecutive driving cycles with fault occur.
TROUBLE SYMPTOM:
• Failure of engine to start
• Improper idling
• Poor driving performance
• Exhaust gas purge performance deterioration
• Black smoke emitted
CAUTION:
After servicing or replacing faulty parts, perform Clear Memory Mode 
and Inspection Mode .
WIRING DIAGRAM:
1.CHECK FOR ANY OTHER DTC ON DISPLAY.
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Is any other DTC displayed?
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Check the appropriate DTC using the “List of Diagnostic Trouble Code (DTC)”.
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2.CHECK HARNESS BETWEEN ECM AND EGR CONTROL VALVE CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and EGR control valve.
3) Measure the resistance of harness between ECM connector and EGR control valve connector.
Connector & terminal
(B134) No. 3 — (E18) No. 1:
(B134) No. 2 — (E18) No. 2:
(B134) No. 57 — (E18) No. 3:
(B134) No. 66 — (E18) No. 4:
(B134) No. 51 — (E18) No. 5:
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Is the resistance less than 1 Ω?
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Repair the harness and connector.
NOTE:
In this case, repair the following item:
• Open circuit of harness between ECM connector and EGR control valve connector
• Poor contact of coupling connector
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3.CHECK HARNESS BETWEEN ECM AND EGR CONTROL VALVE CONNECTOR.
Measure the resistance between EGR control valve connector and engine ground.
Connector & terminal
(E18) No. 1 — Engine ground:
(E18) No. 2 — Engine ground:
(E18) No. 3 — Engine ground:
(E18) No. 4 — Engine ground:
(E18) No. 5 — Engine ground:
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Is the resistance 1 MΩ or more?
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Repair ground short circuit of harness between ECM connector and EGR control valve connector.
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4.CHECK POOR CONTACT.
Check for poor contact of the ECM connector and the EGR control valve connector.
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Is there poor contact of ECM connector or EGR control valve connector?
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Repair poor contact of ECM connector or EGR control valve connector.
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Replace EGR control valve.
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