check engine ISUZU TROOPER 1995 Workshop Manual

AUTOMATIC TRANSMISSION (4L30-E) 7A-79
DIAGNOSTIC TROUBLE CODE (DTC) 13
ENGINE SPEED FAILURE
Install scan tool.
GOTHROUGH
TECH 1 CONNECTION.
I
• Engine running at idle.
• Brake applied.
• Selector lever
position "N" or "P", • Selector "FO: DATA LIST: AT INPUT SPEED".
IF: TECH1 DISPLAY approximately 800 RPM:
I
$
This system is functioning correctly. The problem is probably intermittent. GOTO
I IF: Tachometer displays engine speed? I
'~------------------~
$ c§J
INTERMITTENT CONDITIONS.
r---------------------------------~----~ • Check wire for open or short to ground or short to voltage between Transmission Control Module (TCM) and connector C-90 & C-91, and connector C-91 terminal D12 and ignition control module connector E-21 terminal 4, and check intermediate connector H-5 terminal 5.
• Repair harness. If still not working: GOTO TCM MEM-CAL REPLACEMENT.
• Check wire for open or short to ground or short to voltage between Tachometer connector 1-9 terminal 3 and ignition control module connector E-21 terminal 4 or between these terminals and
intermediate connector H-24
terminal 4. • Repair harness. If still not working: Check Engine electrical section. If still problem, replace ignition control module.

AUTOMATIC TRANSMISSION (4L30-E) 7 A-81
DIAGNOSTIC TROUBLE CODE (DTC) 15
TRANSMISSION OIL TEMPERATURE SHORT TO PLUS OR OPEN
Install scan tool.
GOTHROUGH
TECH1 CONNECTION.
• Ignition switch ON. Engine not running. • Selector lever position "P". • Select "FO: DATA LIST: Trans. Oil Temp". IF: TECH1 DISPLAY more than 4.74 Volts:
•
Connect voltmeter between connector C-90 terminal 83 and connector C-91 ground terminal C1.
IF: If you have more than approximately 4.74 Volts:
• Check
for a short to plus or open between connector C-90 terminal 83 and connector C-91 terminal C14. This faulty connection can be at the connector M-6 terminal 3 (C) or 5 (D). This faulty connection can be
at the intermediate connector
H-1 0 terminals 3 or 11. • Repair If not OK: Disconnect sensor.
• Connect ohmmeter between sensor terminals 3(C) and 5(D).
Refer
to the table of the resistance function of the
temperature.
If resistance not correct, replace the transmission oil temperature sensor.
DTC 15 is intermittent. GOTO INTERMITTENT CONDITIONS.
GOTO TCM MEM-CAL REPLACEMENT.

AUTOMATIC TRANSMISSION (4L30-E) 7 A-83
DIAGNOSTIC TROUBLE CODE (DTC) 16
TRANSMISSION OIL TEMPERATURE SHORT TO GROUND
Install scan tool.
GOTH ROUGH
TECH1 CONNECTION.
• Ignition switch ON. Engine not running.
• Selector lever position "P". • Select "FO: DATA LIST: Trans. Oil Temp".
IF: TECH1 DISPLAY less than 0.4 Volts:
• Connect
voltmeter between connector C-90 terminal 83 and connector C-91 ground terminal C1. IF: If you have less than approximately 0.4 Volts:
• Check
for a short to ground between
connector C-90 terminal 83 and
connector M-6 terminal 3 {C). This faulty connection can be at the
intermediate connector
H-10 terminal 3.
• Repair If not OK: Disconnect sensor. • Connect ohmmeter between sensor terminals 3{C) and 5{D).
Refer
to the table of the resistance
function of the temperature {DTC 15).
If resistance not correct, replace sensor.
DTC 16 is intermittent. GOTO INTERMITTENT CONDITIONS.
GOTO TCM MEM-CAL REPLACEMENT.

7 A-84 AUTOMATIC TRANSMISSION (4L30-E)
DIAGNOSTIC TROUBLE CODE (DTC) 21
THROTTLE POSITION SENSOR SHORT TO PLUS OR OPEN
This DTC flashes the CHECK TRANS indicator and
sets
the BACKUP MODE.
Circuit Description:
• The Throttle Position Sensor (TPS) provides a
voltage signal that changes relative to the throttle
plate position. Signal voltage between connector
C-91 terminals C5 and C6 will vary from about 0.4
at idle to about 4.6 volts at wide open throttle.
• The Engine Control Module (ECM) also receives
this signal. This TPS is a variable resistance with
one side (connector E-5 terminal 2) connected
only to the ECM connector to have the 5 volts
supply voltage. The other side (connector E-5
terminal 1) is connected to the Transmission
Control Module (TCM) (floating ground) and the
ECM (ground). The "middle" (the wiper) (con­
nector E-5 terminal 3) is connected to the TCM
and
the ECM.
• The ECM monitors output voltage from the TPS
and determines fuel delivery based on throttle
valve angle (driver demand).
r---...,
I
I
I
I
I
I
TPS INPUT
I GROUND I L ___ _j
C-91
T C5
I
I
C6
BLU/ORN
BLU/RED
BLU/RED
BLK/WHT
• This TPS is an electrical component and must not
be soaked in any liquid cleaner or solvent, as
damage may result.
Diagnostic Aids:
• This Diagnostic is an electrical test done by the
TCM.
• Detection conditions:
CD Voltage between connector C-91 terminals C5
and C6 > 4.9 volts. This detection occurs
when: The wiper is short to voltage (engine
can
stall) or open.
@ The condition needs to be present for at least
0.5
seconds. Note: during the detection time
the TCM reads "100% (wide open throttle)".
• Action after the detection time: BACKUP MODE.
•
Recovery conditions: To recover when voltage <
or= to 4.9 volts and do an IGNITION CYCLE.
H-5 BLU/ORN
9
BLU/
H-5
RED E-5
-10 3 TO COOLANT TEMPERATURE
1 SENSOR H-5 BLK/WHT
BLK/WHT
11
2 E-5
E-5
THROTTLE POSITION
SENSOR
(TPS)
TRANSMISSION CONTROL MODULE
(TCM)
A1 S.-1_ 06 .,&_2 _ _!>2 C-2
lsvoLT-rps -aRouNDl ENGINE
I REFERENCE INPUT I CONTROL MODULE
I (ECM)
L--------J

AUTOMATIC TRANSMISSION (4L30-E) 7A-85
DIAGNOSTIC TROUBLE CODE (DTC) 21
THROTTLE POSITION SENSOR SHORT TO PLUS OR OPEN
Check Engine Control Module (ECMI DTC.
IF: DTC on Throttle Position Sensor (TPSI exists:
Check diagnosis of ECM and repair. • Install scan tool GOTHROUGH TECH1
CONNECTION. • Ignition switch ON, engine not
running.
• Selector lever position up•.
• Select FO: DATA LIST: "TPS SIGNAL•. IF: TECH1 DISPLAY more than 4.9 volts:
• Connect
voltmeter between connector C-91 terminal C5 and TPS ground
terminal C6. IF: If you have more than 4.9 volts:
• Check
for a short to voltage or open circuit between connector C-91 terminal C5 and connector E-5 terminal 3.
This faulty connection can be at intermediate connector H-5 terminal 10.
The short to voltage only can be at the ECM connector C-2 terminal D6.
• Repair If not OK: Ignition switch OFF. Disconnect connector C-91.
• Connect ohmmeter between connector C-91 terminal C5 and C6. • Check ifthe circuit is open.
• Repair. If not OK: Disconnect sensor. • Connect ohmmeter between sensor terminals 3 wiper and 1 low side. If resistance between TPS terminal 3 and 1 does not change when
the throttle valve angle is changed: Replace TPS.
DTC 21 is intermittent.
GOTO INTERMITTENT CONDmONS.

7A-86 AUTOMATIC TRANSMISSION (4L30-E)
DIAGNOSTIC TROUBLE CODE (DTC) 22
THROTTLE POSITION SENSOR SHORT TO GROUND
This DTC flashes the CHECK TRANS indicator and
sets
the BACKUP MODE.
Circuit Description:
• The Throttle Position Sensor (TPS) provides a
voltage signal that changes relative to the throttle
plate position. Signal voltage between connector
C-91 terminals C5 and C6 will vary from about 0.4
at idle to about 4.6 volts at wide open throttle.
• The Engine Control Module (ECM) also receives
this signal. This TPS is a variable resistance with
one side (connector E-5 terminal 2) connected
only to the ECM connector to have the 5 volts
supply voltage. The other side (connector E-5
terminal 1) is connected to the Transmission
Control Module (TCM) (floating ground) and the
ECM (ground). The "middle" (the wiper) (con­
nector E-5 terminal 3) is connected to the TCM
and the ECM.
• The TCM monitors output voltage from the TPS
and determines fuel delivery based on throttle
r---.,
I
I
I
I
I
I
TPS INPUT
I GROUND I L ___ .J
C-91
T C5
I
I
C6
BLU/ORN
BLU/RED
BLU/RED
BLK!WHT
valve angle (driver demand)
• This TPS is an electrical component and must not
be soaked in any liquid cleaner or solvent, as
damage may result.
Diagnostic Aids:
• This Diagnostic is an electrical test done by the
TCM.
• Detection conditions:
G) This detects a TPS wiper short to TCM ground
(except certain conditions) and wiper short to
TPS low. This also detects a TPS low open.
® Voltage between connector C-91 terminals C5
and C6 < 0.2 volts.
@ The condition needs to be present for at least
0.5
seconds. Note: during the detection time
the TCM reads "0% (idle)".
• Action after the detection time: BACKUP MODE.
•
Recovery conditions: To recover when voltage >
or= to 0.2 volts and do an IGNITION CYCLE.
H-5 BLU/ORN
9
BLU/
H- 5 RED E-5 _. 10 3 TO
COOLANT TEMPERATURE
1 SENSOR, H-5 BLK!WHT
BLK!WHT
11
2
:
E-5
E-5
THROTTLE POSITION
SENSOR
(TPS)
TRANSMISSION CONTROL MODULE
(TCM)
A1 S-1_ D6 ._£2-~2_, C-2
lsvo"Lr -"TP5 -"GRouNDl !REFERENCE INPUT 1
I I t_ ________ J
ENGINE
CONTROL MODULE
(ECM)

AUTOMATIC TRANSMISSION (4L30-E) 7 A-87
DIAGNOSTIC TROUBLE CODE (DTC) 22
THROTTLE POSITION SENSOR SHORT TO GROUND
Check Engine Control Module (ECM) DTC.
IF: DTC on Throttle Position Sensor (TPS) exists:
Check diagnosis
of ECM and repair. • Install scan tool GOTHROUGH TECH1 CONNECTION. • Ignition switch ON, engine not running. • Selector lever position uP".
• Select FO: DATA LIST: "TPS SIGNAL". IF: TECH1 DISPLAY less than 0.2 volts:
• Connect voltmeter between connector C-91 terminal C5 and TPS ground
terminal C6.
IF: If you have less than 0.2 volts:
• Check for a short to ground between connector C-91 terminal C5 and
connector E-5 terminal 3. This faulty connection can be at the intermediate connector H-5 terminal 10.This faulty connection can be at the ECM connector C-2 terminal D6.
• Repair If not OK: Ignition switch OFF. Disconnect sensor connector E-5. • Connect ohmmeter between sensor terminals 3 wiper and 1 low side.
• If resistance between TPS terminal 3 and 1 does not change when
the throttle valve angle is changed: Replace TPS.
DTC 22 is intermittent. GOTO INTERMITTENT
CONDITIONS.

7A-88 AUTOMATIC TRANSMISSION (4l30-E)
DIAGNOSTIC TROUBLE CODE (DTC) 23
THROTTLE POSITION SENSOR CONNECTOR OPEN
This DTC flashes the CHECK TRANS indicator and
sets
the BACKUP MODE.
Circuit Description:
• The Throttle Position Sensor (TPS) provides a
voltage signal that changes relative to the throttle
plate position. Signal voltage between connector
C-91 terminals C5 and C6 will vary from about 0.4
at
idle to about 4.6 volts at wide open throttle.
• The Engine Control Module (ECM) also receives
this signal. This TPS is a variable resistance with
one side (connector E-5 terminal 2) connected
only to the ECM connector to have the 5 volts
supply voltage. The other side (connector E-5
terminal 1) is connected to the Transmission
Control Module (TCM) (floating ground) and the
ECM (ground). The "middle" (the wiper) (con­
nector E-5 terminal 3) is connected to the TCM
and
the ECM.
• The TCM monitors output voltage from the TPS
and
determines fuel delivery based on throttle
valve angle (driver demand).
• This TPS is an electrical component and must not
be soaked in any liquid cleaner or solvent, as
damage may result.
r--...... ..,
I
I
I
TPS INPUT
I GROUND I l ___ _J
C-91
l C5
I
I
C6
BLU/ORN
BLU/RED
BLU/RED
BLKJWHT
A1 ,S.-1_ 06
Diagnostic Aids:
• This Diagnostic is not an electrical test done by
the TCM but a test between different information
("logic test").
• Detection conditions:
G) This detects the terminals C5 and C6 open or
the connector E-5 open.
® Throttle value opening > 42%.
® Engine Speed < 2200 RPM.
@ Vehicle Speed <3 Km/h.
@ No DTC: Engine Speed DTC13, Output Speed
DTC11.
Downshift Protection DTC62.
® Only with Selector Lever in Park or Neutral.
(]) The detection is authorized only during 6
seconds
after the engine is cranked.
® The conditions need to be present for at least
3 seconds.
• Action after the detection time: BACKUP MODE.
• Recovery conditions: To recover do an IGNITION
CYCLE.
TO COOLANT TEMPERATURE SENSOR
BLKJWHT
.,£2_ ~2 C-2
H-5 BLUIORN
9
2
BLU/
H- 5
RED E-5
10 3 .... ,'
1
H-5 BLKJWHT
11
E-5
E-5
THROTILE
POSITION
SENSOR
(TPSI
TRANSMISSION CONTROL MODULE (TCM)
15 VOLT -TPS -GROuNOl ENGINE
I REFERENCE INPUT 1 CONTROL l MODULE I (ECM)
L--------J

AUTOMATIC TRANSMISSION (4L30-E) 7 A-89
DIAGNOSTIC TROUBLE CODE (DTC) 23
THROTTLE POSITION SENSOR CONNECTOR OPEN
Check Engine Control Module (ECM)
DTC.
IF: DTC on Throttle Position Sensor (TPS) exists:
I
Check diagnosis of ECM and repair. • Install scan tool GOTHROUGH TECH1 CONNECTION.
• Ignition switch ON, engine not running.
• Selector lever position "P". • Select FO: DATA LIST: "TPS SIGNAL". IF: TECH 1 DISPLAY approx. 2.5 volts whatever the throttle valve position:
IF: TPS connector E-5 on I the engine is open: DTC 23 is intermittent. GOTO INTERMITTENT
CONDITIONS.
~
NO
Repair. j
• Ignition switch OFF. Disconnect connector C-91. Connect ohmmeter between connector C-91 terminals C5 and C6. If open circuit: • Check for an open between connector C-91 terminal C5 to connector E-5 terminal 3 with a simultaneous open of the terminal C6 to the connector E-5 terminal1. This faulty connection can be at the intermediate connector H-5 terminal 10 and 11.
• Repair. If not OK: Ignition switch OFF. Disconnect sensor.
• Connect ohmmeter between sensor terminals 3 wiper and 1 low side. If resistance between TPS terminal 3 and 1 does not change when the throttle valve angle is changed: Replace TPS.

7 A-90 AUTOMATIC TRANSMISSION (4L30-E)
DIAGNOSTIC TROUBLE CODE (DTC) 25
SUPPLY VOLTAGE TOO LOW
This DTC flashes the CHECK TRANS indicator and
sets the BACKUP
MODE.
Specification decreases with the transmission
oil temperature:
Circuit Description:
-40°C (-40°F) = S.7 volts
90°C (194°F) = 9.0 volts
150°C (304°F) = 9.2 volts The ignition voltage of Transmission Control
Module (TCM) terminals A7 and AS is monitored by
the TCM and when the voltage is too low (approx. 9
volts) the DTC25 is stored and the BACKUP MODE
is set.
@ The condition needs to be present for at least
1 second
• Action after the detection time: BACKUP MODE
Diagnostic Aids:
• This Diagnostic is an electrical test done by the
TCM.
• Recovery conditions: To recover, the ignition
voltage must be higher than specification.
Specification decreases
with the transmission oil
temperature:
-40°C (-40°F) = 9.2 volts
90°C (194°F) = 9.5 volts
150°C (304°F) = 9.6 volts
• Detection conditions:
CD Ignition voltage measured between TCM
terminal A7 or AS and ground C1 is lower
than specification .
. · fU I
I '
f:L;~soA L., ____ J
RELAY & FUSE BOX
1--, {)-:,.--____..J BATTERY
l
T
L __ I
r
I C-14 C-8 I I 15A 15A FUSE -__ + _ j BOX
H-13t 3
H-7 'x~.~~'---7 r ]_-
GRN/WHT
BATTERY I GROUND INPUT IGNITION I INPUT I
L-----------TRANSMISSION
CONTROL MODULE
(TCM) IGN.SW.
RED/WHT
C-1 C-1 C-2
A6 B1 C16
r -;ATTERV INPUT-l
I
I l _____ j
ENGINE
CONTROL MODULE
(ECM)
I I
I-_j GENERATOR