Page 444 of 1767
DIAGNOSTIC PROCEDURE
1 INSPECTION START
Start engine.
Is engine running?
YesorNo
Ye sEGO TO 14.
NoEGO 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
OKEGO TO 4.
NGEGO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
I10A fuse
IHarness 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
OKEGO TO 6.
NGEGO TO 5.
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-82
Page 445 of 1767
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F108, E225
IHarness connectors M842, F135 (RHD models)
IHarness 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
OKECheck electronic control fuel injection pump power supply circuit. Refer to ªDiagnostic
Procedureº, EC-180.
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
Page 449 of 1767

17 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M787, F66 (LHD models)
IHarness for open or short between ECM and ECM relay
ERepair open circuit or short to ground or short to power in harness or connectors.
18 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminals 39, 43, 106, 112, 118 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OKEGO TO 20.
NGEGO TO 19.
19 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F108, E225
IHarness connectors M842, F135 (RHD models)
IHarness for open or short between ECM and engine ground
ERepair open circuit or short to ground or short to power in harness or connectors.
20 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-78.
EINSPECTION END
TROUBLE DIAGNOSIS FOR POWER SUPPLYZD30DDTi
Main Power Supply and Ground Circuit
(Cont'd)
EC-87
Page 450 of 1767

Component Description
The mass air flow sensor (MAFS) is placed in the stream of intake
air. It measures the intake air flow rate by measuring a part of the
entire intake air flow. It consists of a hot wire that is supplied with
electric current from the ECM. The temperature of the hot wire is
controlled by the ECM a certain amount. The heat generated by the
hot wire is reduced as the intake air flows around it. The more air,
the greater the heat loss.
Therefore, the ECM must supply more electric current to maintain
the temperature of the hot wire as air flow increases. The ECM
detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor
Mode
Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS AIR/FL SEIEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: Neutral position
INo-loadIdle 1.6 - 2.0V
ECM Terminals and Reference Value
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
COLORITEM CONDITION DATA (DC Voltage)
35 R Mass air flow sensorEngine is running.
Warm-up condition
Idle speed1.6 - 2.0V
49 W Sensor's power supply Ignition switch ªONº
Approximately 5V
50 B Sensor's groundEngine is running.
Warm-up condition
Idle speedApproximately 0V
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
IAn excessively high or low voltage from the sensor is sent to
ECM.IHarness or connectors
(The sensor circuit is open or shorted.)
IMass air flow sensor
SEF987W
DTC 0102 MASS AIR FLOW SENZD30DDTi
EC-88
Page 455 of 1767

3 CHECK MAFS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
MEC994D
3. Check harness continuity between mass air flow sensor terminal 3 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
OKEGO TO 5.
NGEGO TO 4.
4 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F135, M842 (RHD models)
IHarness for open or short between mass air flow sensor and ECM
ERepair open circuit or short to ground or short to power in harness or connectors.
5 CHECK MAFS INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between mass air flow sensor terminal 5 and ECM terminal 35. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OKEGO TO 7.
NGEGO TO 6.
6 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F135, M842 (RHD models)
IHarness for open or short between mass air flow sensor and ECM
ERepair open circuit or short to ground or short to power in harness or connectors.
DTC 0102 MASS AIR FLOW SENZD30DDTi
Diagnostic Procedure (Cont'd)
EC-93
Page 456 of 1767
7 CHECK MASS AIR FLOW SENSOR
1. Reconnect harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Check voltage between ECM terminal 35 (Mass air flow sensor signal) and ground.
SEF400Y
4. If the voltage is out of specification, disconnect MAFS harness connector and connect it again.
Then repeat above check.
OK or NG
OKEGO TO 8.
NGEReplace mass air flow sensor.
8 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-78.
EINSPECTION END
DTC 0102 MASS AIR FLOW SENZD30DDTi
Diagnostic Procedure (Cont'd)
EC-94
Page 457 of 1767

Description
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine cool-
ant temperature input. The sensor uses a thermistor which is sen-
sitive to the change in temperature. The electrical resistance of the
thermistor decreases as temperature increases.
Engine coolant tempera-
ture ÉC (ÉF)Voltage* (V) Resistance (kW)
þ10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.3 0.68 - 1.00
90 (194) 1.0 0.236 - 0.260
*: These data are reference values and measured between ECM terminal 19
(Engine coolant temperature sensor) 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.
On Board Diagnosis Logic
Malfunction is detected when ... Check Items (Possible Cause)
IAn excessively high or low voltage from the sensor is entered
to ECM.IHarness or connectors (The sensor circuit is open or shorted.)
IEngine coolant temperature sensor
DTC Confirmation Procedure
WITH CONSULT-II
1) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 5 seconds.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-97.
WITHOUT CONSULT-II
1) Turn ignition switch ªONº and wait at least 5 seconds.
2) Turn ignition switch ªOFFº, wait at least 5 seconds and then turn
ªONº.
3) Perform ªDiagnostic Test Mode II (Self-diagnostic results)º with
ECM.
4) If DTC is detected, go to ªDiagnostic Procedureº, EC-97.
SEF594K
SEF012P
SEF817Y
DTC 0103 COOLANT TEMP SENZD30DDTi
EC-95
Page 459 of 1767
Diagnostic Procedure
1 CHECK ECTS POWER SUPPLY CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect engine coolant temperature sensor harness connector.
MEC022E
3. Turn ignition switch ªONº.
4. Check voltage between ECTS terminal 2 and ground with CONSULT-II or tester.
SEF401Y
OK or NG
OKEGO TO 3.
NGEGO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E225, F108
IHarness connectors F135, M842 (RHD models)
IHarness for open or short between engine control temperature sensor and ECM
ERepair open circuit or short to ground or short to power in harness or connectors.
3 CHECK ECTS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between ECTS terminal 1 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to ground and short to power.
OK or NG
OKEGO TO 5.
NGEGO TO 4.
DTC 0103 COOLANT TEMP SENZD30DDTi
EC-97