2. LA HIPÓTESIS METODOLÓGICA:
2.4. De la matriz al defecto
E-1 Starter does not rotate even if key switch is turned to START position.
This problem is contributed to by many different causes. Diagnose the power system and the relay system separately to locate the cause of the prob-lem.
• The electrical system is diagnosed in this group.
In case the starter does not rotate due to failure in the engine unit, refer to the engine service manual.
• The same problem will be presented in case ei-ther the valve switch or the engine stop switch is activated. Check each switch condition first.
• Check for loose harness connections before-hand.
(1) (2)
NO YES
· Key switch: ON
·Key switch: START Check for voltage at starter motor terminal C.
Check if voltage at starter motor terminal B is 24 V or over.
Faulty starter unit, or faulty engine unit.
To Power System Troubleshooting (T5-5-15) To Relay System Troubleshooting (T5-5-16)
24 V 0 V.
Terminal B Terminal C
Terminal M
(1) Power System Troubleshooting
Connector
T146-05-04-018
Battery Relay
(1)
All starters indicate 0 V Certain starter
indicates 0 V
Faulty battery re-lay, or faulty ground wire from battery relay ter-minal E.
Broken harness between battery relay terminal S and fuse #10.
Broken harness between battery relay terminal A and battery.
Broken harness between battery relay terminal B and starter terminal B.
Blown fuse #10, or broken harness between key switch terminal M and battery relay terminal S.
Check if voltage at battery relay ter-minal S is 24 V or over.
Check if voltage at battery relay ter-minal B connected to corresponding starter is 24 V or over.
Check if voltage at battery relay ter-minal A is 24 V or over.
(2) Relay System Troubleshooting
Connector
Starter Relay 1 Starter Relay 2 Starter Relay 1 Starter Relay 2
Check if voltage at starter relay connector termi-nal #1 is beyond 24V.
Blown fuse of fuse box 2 terminal #19, or broken harness between key switch terminal G2 and starter relay con-nector terminal #1.
· Key switch: START
YES
YES
NO
NO
Check if voltage at starter relay 1 and 2 output side is
be-yond 24V. Faulty starter relay.
Broken harness between starter relay and starter relay 1 or 2.
YES
NO
NO YES Disconnect starter
relay 1 and 2 ter-minal E. Check for continuity between harness end termi-nal E and vehicle frame.
Faulty ground of starter relay termi-nal #2.
Broken harness between starter re-lay 1 and starter motor 1 or starter relay 2 and starter motor 2.
YES
Faulty starter relay 1 or 2.
NO Check for continu-ity between ter-minal B and C.
Remove starter relay 1 and 2 ter-minal #2. Check for continuity be-tween terminal #2 and vehicle frame.
Faulty starter relay 1 or 2 ground.
YES
NO Check if voltage
at starter relay 1 and 2 terminal S is beyond 24V.
(Blank)
E-2 Although starter rotates, engine does not start.
Connector
ECM Connector 21 Poles ECM Connector 31 Poles
Remove ECM connector 21 poles.
Check if voltage at harness end connector termi-nals #G and #D is 24V respectively.
· Key switch: ON
· Key switch: OFF
YES
YES
Check if voltage at fuse box terminal #2 is 24V.
NO
NO
NO YES
Check if voltage at input side of fuse box 2 terminal #3 is
Remove connector 31 poles. Check if voltage at harness end connector ter-minal #1 is 24V.
YES
NO
Blown fuse terminal
#1, or broken har-ness between fuse box 2 terminal #2 and ECM.
Broken harness be-tween fuse box and key switch terminal M.
Faulty engine.
(Refer to the Engine Manual)
Bleed air from cou-pling of engine injec-tion pump.
Blown fuse of fuse box terminal #3, or broken harness be-tween fuse box and ECM.
Broken harness be-tween fuse box and key switch terminal M.
#G #1
(Blank)
E-3 Even if engine control dial is rotated, engine speed remains unchanged.
• The engine control dial, ECM and/or harness may have trouble. In those cases, fault code 10 is displayed on the built-in diagnosing system.
Refer to Troubleshooting A.
E-4 Even if key switch is turned OFF, engine does not stop.
• The key switch may be faulty.
• If the above are not the cause, the engine unit may have trouble.
E-5 Engine speed is slow, or does not increase.
• The engine control dial system of the switch box and/or ECM system may have trouble.
• Check for loose harness connections before-hand.
Check if resistance between switch box terminals #2 and
#4 is normal.
Insert probe in switch box connector rear terminals #2 and #3. Check if voltage at those terminals matches specification.
Disconnect switch box.
Check if voltage between harness end connector terminal #2 and terminal
#4 matches specification.
Faulty engine control dial.
Connect switch box harness end connector terminal #3 and vehicle frame.
Disconnect EMC connector 31 poles.
Check for continuity between ECM harness end connector terminal #5 and vehicle frame.
· Resistance specification:
5±0.5 kΩ
· Voltage specification:
0.3 to 1 V
(at maximum speed)
Check if voltage between switch box harness end con-nector terminal #4 and vehicle frame matches specification.
· Key switch: ON
Connector
(Harness End Connector Viewed from the Open End Side)
Switch Box
T183-05-04-004
ECM Connector 31 Poles
T18E-05-04-004
Broken harness between switch box and ECM (sensor system).
Broken harness between switch box and ECM (power system).
Disconnect ECM connector 31 poles.
Check for continuity between EMC connector 31 poles terminal #6 and switch box harness end connector
ter-minal #2. Broken harness between
switch box and ECM (ground system).
Faulty ECM system.
Faulty ECM system.
NO YES
YES YES
NO NO
E-6 Quick-idle system is inoperable.
• Check for loose harness connections before-hand.
NOTE: When the auto-idle switch is turned ON, the quick-idle system operates after 3 seconds.
Connector
Monitor Controller
Connector B Connector C
· Engine: Running
· Control lever: Neutral
Faulty quick-idle switch.
Faulty monitor con-troller.
Disconnect quick-idle switch.
Connect harness end connector ter-minals with a clip.
Check if quick-idle system is operated.
YES
NO YES
NO
Disconnect ECM connector 31 poles.
Check for continuity between monitor con-troller connector ter-minal #C3 and ECM connector 31 poles harness end terminal
#19.
Disconnect monitor controller connector C.
Check for continuity between monitor con-troller terminal #C3 YES
NO Disconnect monitor
controller connector B.
Check for continuity between monitor controller harness end connector ter-minal #B11 and quick-idle switch end terminal.
Broken harness be-tween monitor con-troller and quick-idle switch.
C3
ECM Connector 31 Poles
T18E-05-04-004
Broken harness between ECM and monitor controller.
NO
YES
Faulty ECM.
19
E-7 Auto-idle system is inoperable.
• The auto-idle system will stop if one of pressure switches is turned ON.
• Check for loose harness connections before-hand.
Connector
Faulty switch box.
· Key switch: START
· Auto-idle switch: ON
· Control lever: Neutral
YES
YES
NO
NO
Broken harness between main con-troller A and switch box.
Connect connector.
Disconnect main controller A con-nector A.
Check for continuity between main con-troller terminal #A29 and vehicle frame.
YES
Broken harness between main con-troller and ECM.
NO Disconnect ECM connector 31 poles.
Connect main controller con-nector A terminal
#A29 to vehicle frame.
Check for continu-ity between ECM connector 31 poles terminal #20 and vehicle frame.
Faulty main con-troller A.
YES
NO Connect
connec-tor.
Disconnect main controller A con-nector B.
Check for conti-nuity between harness end connector termi-nal #B16 and ve-hicle frame.
Faulty ECM.
Disconnect har-ness from switch box.
Check for conti-nuity between switch box con-nector terminal #8 and vehicle
(Blank)
E-8 Even if control lever is operated, speed does not increase.
(with auto-idle ON)
• The pilot sensor (front attachment), main control-ler A and/or harness may have trouble. In either cases, fault code 08 is displayed on the built-in diagnosing system.
Refer to Troubleshooting A.