Page 5804 of 6000

AUTOMATIC TRANSMISSION (AW30-40LE) 7A–23
INTERMITTENT CONDITIONS
If the Tech2 displays a code as intermittent, or if after a
test drive a code does not reappear, the problem is most
likely a faulty electrical connection or loose wiring.
Terminals should always be the prime suspect.
Intermittent rarely occur in sophisticated electronic
components such as the Transmission Control Module
(TCM).
When an intermittent problem is encountered, check
suspect circuits for:
• Poor terminal to wire connection.
• Terminals not fully seated in the connector body
(backed out).
• Improperly formed or damaged terminals.
• Loose, dirty, or corroded ground connections.
HINT: Any time you have an intermittent in more than
one circuit, check whether the circuits share a
common ground connection.
• Pinched or damaged wires.
• Electro-Magnetic Interference (EMI)
HINT: Check that all wires are properly routed away
from spark plug wires, distributor wires, coil,
and generator. Also check for improperly
installed electrical options, such as lights, 2-
way radios, etc.
Use the F2: SNAPSHOT mode of the Tech2 to help
isolate the cause of an intermittent fault. The snapshot
mode will record information before and after the
problem occurs. Set the snapshot to "trigger" on the
suspect code (or codes) or, if you notice the repor ted
symptom during test drive, trigger the snapshot
manually.
After the snapshot has been triggered, command the
Tech2 to play back the flow of data recorded from each
of the various sensors. Signs of an intermittent fault in a
sensor circuit are a sudden unexplainable jump in data
values out of the normal range.
Page 5805 of 6000
7A–24 AUTOMATIC TRANSMISSION (AW30-40LE)
826RY00004
IDENTIFICATION OF TRANSMISSION
CONTROL MODULE (TCM)
ISUZU Part No: 8-97230-821-0
Page 5806 of 6000
AUTOMATIC TRANSMISSION (AW30-40LE) 7A–25
DIAGNOSTIC TROUBLE CODES (DTC) CHECK
DTC
NUMBERFLASHING
CODEDESCRIPTION
P0120 21 ANALOG THROTTLE SIGNAL FAILURE (VTH)
P0502 24 SPEED METER SENSOR FAILURE (SP1)
P0705 17 GEAR SELECTOR FAILURE (PRND2L)
P0710 16 OIL TEMPERATURE SENSOR FAILURE (OT2)
P0717 14 INPUT REVOLUTION SENSOR FAILURE (NC0)
P0722 11 OUTPUT REVOLUTION SENSOR FAILURE (SP2)
P0727 13 ENGINE REVOLUTION SIGNAL FAILURE (NE)
P0743 33 TORQUE CONVERTER CLUTCH CONTROL LOCK-UP (ON/OFF) SOLENOID
FA I L U R E ( S L )
P0748 35 PRESSURE CONTROL SOLENOID FAILURE (STH)
P0753 31 SOLENOID 1 FAILURE (S1)
P0758 32 SOLENOID 2 FAILURE (S2)
P1121 23 ANALOG THROTTLE SIGNAL FAILURE (VREF, VGND)
Page 5807 of 6000

7A–26 AUTOMATIC TRANSMISSION (AW30-40LE)
DTC P0120 (FLASHING CODE 21) ANALOG THROTTLE SIGNAL FAILURE (VTH)
D07RY00023Circuit description:
When the signal of the engine throttle position sensor
located on the accelerator pedal is supplied to the TCM,
the TCM judges the opening condition of the throttle.
The shift point of the transmission is determined by this
opening condition of the throttle.
Fail-safe control:
The TCM controls fail-safe by detecting analog throttle
signal (VTH) failure.
Failure detection:
•When the throttle input voltage is detected less than
0.112V or more than 4.417V for 2.0 seconds.
Contents of control:
At failure detection
•Throttle opening for line pressure control ... Throttle
opening 100%
•Throttle opening for shift control ... Throttle opening
0%
•Lock-up control inhibit
•Up hill and down hill control inhibit
•Squat control inhibit
At failure decision
Executes following items in addition to above control
items at failure detection.
•Blinks "CHECK TRANS" lamp
•Stores the failure information in failure-memory
Conditions of turning "CHECK TRANS" lamp off:
Turns “CHECK TRANS” lamp off when judged 0km/h by
output revolution sensor after throttle signal input voltage
is detected more than 0.112V and less than 4.717V.
(however, uses 0 km/h judgment by back-up vehicle
speed at output revolution failure)Reversion conditions from fail-safe:
At failure detection
Immediately recovers when the throttle input voltage
is detected more than 0.112V and less than 4.717V.
At failure decision
Recovers at the same time as the conditions of
turning “CHECK TRANS” lamp off are satisfied.
Test description:
The following numbers correspond to circled numbers on
the diagnostic char t.
(1) Check that the throttle input voltage is 0.25 to 0.45V.
(2)At this test, check that as the throttle opens, the
voltage goes up and that the voltage reaches 3.74 to
4.56V at the full open status.
(3) Check the power supply voltage (4.75 – 5.25V) of the
throttle position sensor.
Diagnostic aids:
An intermittent may be caused by a poor connection,
rubbed through wire insulation or a wire broken inside
the insulation. Inspect related harness connector for
backed out terminals, improper mating, broken locks,
improperly formed or damaged terminals, poor terminal
to wire connection and damaged harness.
Page 5808 of 6000
AUTOMATIC TRANSMISSION (AW30-40LE) 7A–27
DTC P0120 (FLASHING CODE 21) ANALOG THROTTLE SIGNAL FAILURE (VTH)
DTCP0120
Page 5809 of 6000

7A–28 AUTOMATIC TRANSMISSION (AW30-40LE)
DTC P0502 (FLASHING CODE 24) SPEED METER SENSOR FAILURE (SP1)
D07RY00024Circuit description:
Speed information is provided by the speed meter sensor
to the meter.
In the meter, the pulses of the speed meter sensor are
converted to speed signals (pulses), and these signals
are output to the TCM. The TCM converts these pulse
voltages to km/h signals.
Fail-safe control:
The TCM controls fail-safe by detecting speed meter
signal failure.
Failure detection:
• When not even 1 pulse is input in the speed meter
signal during the time 100 pulses are input in the
output revolution sensor signal.
• When not even 1 pulse is input in the speed meter
signal during the time 27 pulses are input in the
output revolution sensor signal.
Contents of control:
At failure detection
•Keeps the condition of transfer (High/Low judgment)
just before detection until vehicle speed is 0km/h,
and changes shift map to L4 map (3
4 UP None) at
vehicle speed is 0km/h.
•Uses high oil temperature map according to shift
map priority at correct oil temperature control.
• Up hill and down hill control inhibit.
• Stores the failure information in failure -memory.
• The failure detection of oil temperature sensor inhibit
At failure decision
Executes following items in adition to above control
items at failure detection.
•Blinks "CHECK TRANS" lamp
Conditions of turning "CHECK TRANS" lamp off:
Turns "CHECK TRANS" lamp off when judged 0km/h by
speed meter sensor after more than 1 pulse are input in
the speed meter signal during the time 27 pulses areinput in the output revolution sensor.
Reversion conditions from fail-safe:
At failure detection and decision
Recovers at the same time as the conditions of turning
“CHECK TRANS” lamp off are satisfied.
Test description:
The following numbers correspond to circled numbers on
the diagnostic char t.
(1) The cause of DTC P0502 setting is due to the
operation fault of the speed meter.
(2) Speed signals are output from the meter. The sensor
power supply is given from the TCM.
Diagnostic aids:
An intermittent may be caused by a poor connection,
rubbed through wire insulation or a wire broken inside
the insulation. Inspect related harness connector for
backed out terminals, improper mating, broken locks,
improperly formed or damaged terminals, poor terminal
to wire connection and damaged harness.
Page 5810 of 6000
AUTOMATIC TRANSMISSION (AW30-40LE) 7A–29
DTC P0502 (FLASHING CODE 24) SPEED METER SENSOR FAILURE (SP1)
DTCP0502
Page 5811 of 6000

7A–30 AUTOMATIC TRANSMISSION (AW30-40LE)
DTC P0705 (FLASHING CODE 17) GEAR SELECTOR FAILURE (PRND2L)
D07RY00022Circuit description:
The neutral start switch gives the signals related to the
selector lever position (PRND2L) to the Transmission
Control Module (TCM). The neutral star t switch turns on
when the select lever is shifted to the P, R, N, D, 2 or L
range. The neutral star t switch, which is connected to the
starter switch circuit, is available only when the select
lever is in the P or N range
The neutral start switch is connected to the transmission
manual shaft and installed in the transmission case.
Fail-safe condition:
The TCM controls fail-safe by detecting selector position
switch fail ure.
Failure detection:
(1) OPEN:
• When all switches are OFF
• When the failure criteria continues for 30 seconds
if the vehicle speed which is calculated by output
revolution sensor is more than 30 km/h and the
engine revolution is more than 1500 rpm.
(2) SHORT:
• When more than two switches are ON at the same
time.
• When the failure criteria condition for 10 seconds.
Contents of control:
At failure detection
(1) OPEN: D range judgment
(2) SHORT: Judged by priority D>2>L>R>N>P
•Up hill and down hill control inhibit
•Winter mode inhibitAt failure decision
Excutes following items in addition to above control
items at failure detection.
•Blinks "CHECK TRANS" lamp
•Stores the failure information in failure-memory
•Reverse lockout control inhibit
Conditions of turning “CHECK TRANS” off:
Turns “CHECK TRANS” lamp off when only one of all
switches is ON.
Reversion conditions from fail-safe:
Turns “CHECK TRANS” lamp off when only one of all
switches is ON.
Test description:
The following numbers correspond to circled numbers on
the diagnostic char t.
(1) It is judged whether the input signal received from
the neutral star t switch by the TCM is proper or not.
(2)The power status of the neutral start switch is
checked.
(3) The continuity between neutral star t switch terminals
and the continuity of the wire connected to the
neutral start switch are checked.
Diagnostic aids:
An intermittent may be caused by a poor connection,
rubbed through wire insulation or a wire broken inside
the insulation. Inspect related harness connector for
backed out terminals, improper mating, broken locks,
improperly formed or damaged terminals, poor terminal
to wire connection and damaged harness.