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SEF615Z
TROUBLE DIAGNOSIS Ð SPECIFICATION VALUEQG18DE
Diagnostic Procedure (Cont'd)
EC-144
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DescriptionNLEC0045Intermittent 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 (1st trip) 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 indi-
cate the specific problem area.
COMMON I/I REPORT SITUATIONSNLEC0045S01
STEP in Work Flow Situation
IIThe CONSULT-II is used. The SELF-DIAG RESULTS screen shows time data other than ª0º or
ª1tº.
III The symptom described by the customer does not recur.
IV (1st trip) DTC data does not appear during the DTC Confirmation Procedure.
VI The Diagnostic Procedure for PXXXX does not indicate the problem area.
Diagnostic ProcedureNLEC0046
1 INSPECTION START
Erase (1st trip) DTCs. Refer to ªHow to Erase Emission-related Diagnostic Informationº, EC-69, EC-71.
©GO TO 2.
2 CHECK GROUND TERMINALS
Check ground terminals for corroding or loose connection. Refer to GI-27, ªGROUND INSPECTIONº.
OK or NG
OK©GO TO 3.
NG©Repair or replace.
3 SEARCH FOR ELECTRICAL INCIDENT
Perform GI-22, ªIncident Simulation Testsº.
OK or NG
OK©INSPECTION END
NG©Repair or replace.
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTQG18DE
Description
EC-145
Page 571 of 3051
Main Power Supply and Ground Circuit
WIRING DIAGRAMNLEC0047Models with ECM in engine compartmentNLEC0047S01
YEC650
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG18DE
Main Power Supply and Ground Circuit
EC-146
Page 572 of 3051
Models with ECM in cabinNLEC0047S02
YEC872
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG18DE
Main Power Supply and Ground Circuit (Cont'd)
EC-147
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ECM TERMINALS AND REFERENCE VALUENLEC0048Specification 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 result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
31 W/G ECM relay (Self shut-off)[Engine is running]
[Ignition switch ªOFFº]
+For 9 seconds after turning ignition switch ªOFFº0-1V
[Ignition switch ªOFFº]
+9 seconds passed after turning ignition switch
ªOFFºBATTERY VOLTAGE
(11 - 14V)
43 B/R Ignition switch[Ignition switch ªOFFº]0V
[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
48 B ECM ground[Engine is running]
+Idle speedEngine ground
57 B ECM ground[Engine is running]
+Idle speedEngine ground
67 W/LPower supply for ECM
(Back-up)[Ignition switch ªOFFº]BATTERY VOLTAGE
(11 - 14V)
106
108B/Y
B/YECM ground[Engine is running]
+Idle speedEngine ground
11 0
11 2W
WPower supply for ECM[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
DIAGNOSTIC PROCEDURENLEC0565
1 INSPECTION START
Start engine.
Is engine running?
YesorNo
Ye s©GO TO 9.
No©GO TO 2.
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG18DE
Main Power Supply and Ground Circuit (Cont'd)
EC-148
Page 574 of 3051
2 CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ªOFFº and then ªONº.
2. Check voltage between ECM terminal 43 and ground with CONSULT-II or tester.
SEF291X
OK or NG
OK©GO TO 4.
NG©GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors M50, F44 (where fitted)
+Harness connectors M72, F44 (where fitted)
+Fuse block (J/B) connector M1, E108
+10A fuse
+Harness for open or short between ECM and ignition switch
©Repair harness or connectors.
4 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 48, 57, 106, 108 and engine ground.
Refer to WIRING DIAGRAM.
Continuity should exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 5.
NG©Repair open circuit or short to power in harness or connectors.
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG18DE
Main Power Supply and Ground Circuit (Cont'd)
EC-149
Page 575 of 3051

5 CHECK POWER SUPPLY-II
1. Disconnect ECM relay. (For ECM relay location, refer to ªEngine Control Compartment Parts Locationº.)
2. Check voltage between ECM relay terminals 1, 6 and ground with CONSULT-II or tester.
SEF101Y
OK or NG
OK©GO TO 7.
NG©GO TO 6.
6 DETECT MALFUNCTIONING PART
Check the following.
+10A fuses
+Harness connectors E76, F36
+Harness connectors M72, F44 (where fitted)
+Harness connectors M11, E106 (LHD models) (where fitted)
+Harness connectors M78, E120 (RHD models) (where fitted)
+Joint connector F46 (where fitted)
+Harness for open or short between ECM relay and battery
©Repair open circuit or short to ground or short to power in harness or connectors.
7 CHECK OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 31 and ECM relay terminal 2.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OK©Go to ªIGNITION SIGNALº, EC-500.
NG©GO TO 8.
8 DETECT MALFUNCTIONING PART
Check the harness for open or short between ECM relay and ECM.
©Repair open circuit or short to ground or short to power in harness or connectors.
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG18DE
Main Power Supply and Ground Circuit (Cont'd)
EC-150
Page 576 of 3051
9 CHECK ECM POWER SUPPLY CIRCUIT-II
1. Stop engine.
2. Check voltage between ECM terminal 67 and ground with CONSULT-II or tester.
SEF293X
OK or NG
OK©GO TO 11.
NG©GO TO 10.
10 DETECT MALFUNCTIONING PART
Check the following.
+Harness connectors E76, F36
+Harness connectors M72, F44 (where fitted)
+Harness connectors M11, E106 (LHD models) (where fitted)
+Harness connectors M78, E120 (RHD models) (where fitted)
+Joint connector F46 (where fitted)
+Harness for open or short between ECM and fuse
©Repair harness or connectors.
11 CHECK ECM POWER SUPPLY CIRCUIT-III
1. Turn ignition switch ªONº and then ªOFFº.
2. Check voltage between ECM terminals 110, 112 and ground with CONSULT-II or tester.
SEF294X
OK or NG
OK©GO TO 17.
NG (Battery voltage
does not exist.)©GO TO 12.
NG (Battery voltage
exists for more than a
few seconds.)©GO TO 14.
TROUBLE DIAGNOSIS FOR POWER SUPPLYQG18DE
Main Power Supply and Ground Circuit (Cont'd)
EC-151