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Description
Intermittent incidents (I/I) may occur. In many cases, the problem resolves itself (the part or circuit function
returns to normal without intervention). It is important to realize that the symptoms described in the custom-
er's complaint often do not recur on DTC visits. Realize also that the most frequent cause of I/I occurrences
is poor electrical connections. Because of this, the conditions under which the incident occurred may not be
clear. Therefore, circuit checks made as part of the standard diagnostic procedure may not indicate the spe-
cific problem area.
COMMON I/I REPORT SITUATIONS
STEP in Work FlowSituation
II The CONSULT-II is used. The SELF-DIAG RESULTS screen shows time data other than ª0º.
III The symptom described by the customer does not recur.
IV DTC does not appear during the DTC Confirmation Procedure.
VI The Diagnostic Procedure for XXXX does not indicate the problem area.
Diagnostic Procedure
1 INSPECTION START
Erase DTCs. Refer to ªHOW TO ERASE DTCº, EC-33.
EGO TO 2.
2 CHECK GROUND TERMINALS
Check ground terminals for corroding or loose connection.
Refer to GI section (ªGROUND INSPECTIONº, ªCircuit Inspectionº).
OK or NG
OK EGO TO 3.
NG ERepair or replace.
3 SEARCH FOR ELECTRICAL INCIDENT
Perform GI section, ªIncident Simulation Testsº.
OK or NG
OK EINSPECTION END
NG ERepair or replace.
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTZD30DDTi
EC-78
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Main Power Supply and Ground Circuit
ECM TERMINALS AND REFERENCE VALUE
Remarks: Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may damage the
ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
4 G ECM relay (Self-shutoff) Ignition switch ªONº
Ignition switch ªOFFº
For a few seconds after turning ignition switch
ªOFFº
Approximately 0.25V
Ignition switch ªOFFº
More than a few seconds after turning ignition
switch ªOFFº BATTERY VOLTAGE
(11 - 14V)
38 B/W Ignition switch Ignition switch ªOFFº
0V
Ignition switch ªONº
BATTERY VOLTAGE
(11 - 14V)
39
43 B
B
ECM ground Engine is running.
Idle speed Approximately 0V
56
61
11 6 B/W
B/W
B/W
Power supply for ECM Ignition switch ªONº
BATTERY VOLTAGE
(11 - 14V)
102 G/W Current return Engine is running.
Idle speed BATTERY VOLTAGE
(11 - 14V)
106 11 2
11 8 B
B
B
ECM ground
Engine is running.
Idle speed Approximately 0V
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
EC-79
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Page 355 of 1833
WIRING DIAGRAM
YEC171A
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)EC-80
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YEC172A
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)EC-81
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DIAGNOSTIC PROCEDURE
1 INSPECTION START
Start engine.
Is engine running?YesorNo
Ye s EGO TO 14.
No EGO TO 2.
2 CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ªONº.
2. Check voltage between ECM terminal 38 and ground with CONSULT-II or tester.
SEF397Y
OK or NG
OK EGO TO 4.
NG EGO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
I10A fuse
I Harness for open or short between ECM and fuse
ERepair open circuit or short to ground or short to power in harness or connectors.
4 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 39, 43, 106, 112, 118 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK EGO TO 6.
NG EGO TO 5.
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-82
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Page 358 of 1833
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F108, E225
I Harness connectors M842, F135 (RHD models)
I Harness for open or short between ECM and engine ground
ERepair open circuit or short to ground or short to power in harness or connectors.
6 CHECK ECM POWER SUPPLY CIRCUIT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ªONº and then ªOFFº.
3. Check voltage between ECM terminals 56, 61, 116 and ground with CONSULT-II or tester.
SEF288Z
OK or NG
OK ECheck electronic control fuel injection pump power supply circuit. Refer to ªDiagnostic
Procedureº, EC-185.
NG (Battery voltage does not
exist.) EGO TO 7.
NG (Battery voltage exists for
more than a few seconds.) EGO TO 13.
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-83
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Page 359 of 1833
7 CHECK ECM POWER SUPPLY CIRCUIT-III
1. Disconnect ECM relay.
MEC021E
2. Check voltage between relay terminals 2, 3 and ground with CONSULT-II or tester.
MEC978DVoltage: Battery VoltageOK or NG
OK EGO TO 9.
NG EGO TO 8.
8 DETECT MALFUNCTIONING PART
Check the following.
I10A fuse
I 15A fuse
I Harness for open or short between ECM relay and battery
ERepair open circuit or short to ground or short to power in harness or connectors.
9 CHECK OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 4 and ECM relay terminal 1. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OK EGO TO 11.
NG EGO TO 10.
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-84
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10 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M787, F66 (LHD models)
I Harness for open or short between ECM and ECM relay
ERepair open circuit or short to ground or short to power in harness or connectors.
11 CHECK ECM POWER SUPPLY CIRCUIT-IV
1. Check harness continuity between ECM terminals 56, 61, 116 and ECM relay terminal 5. Refer to Wiring Diagram.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OK EGO TO 13.
NG EGO TO 12.
12 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M787, F66 (LHD models)
I Harness for open or short between ECM and ECM relay
ERepair open circuit or short to ground or short to power in harness or connectors.
13 CHECK ECM RELAY
1. Apply 12V direct current between ECM relay terminals 1 and 2.
2. Check continuity between ECM relay terminals 3 and 5, 6 and 7.
SEF296X
OK or NG
OK EGO TO 14.
NG EReplace ECM relay.
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-85
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