TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–11
Diagnosis
Electronic Diagnosis
How To Diagnose The Problem
1. To avoid incorrect diagnostics, this book needs to be
followed accurately. Unless stated, do not jump
directly to a section that could contain the solution.
Some important information may be missed.
2. The sections in CAPITALS and bold are the main
sections that can be found in the contents.
3. The GOTO “SECTION” means to continue to check
going to the “section”.
4. The GOTHROUGH “SECTION” means to go
through the “section” and then to go back to the place
the GOTHROUGH was written.
5. BASIC ELECTRIC CIRCUITS:
You should understand the basic theory of electricity.
This includes the meaning of voltage, amps, ohms,
and what happens in a circuit with an open or shorted
wire. You should also be able to read and understand
wiring diagrams.
Check Trans Indicator
Find CHECK TRANS indicator and verify if it is
A. Flashing: GOTO DIAGNOSTIC CHECK.
B. Staying on: GOTHROUGH CHECK TRANS
CHECK.
C. Is never ON when the ignition key is turned on:
GOTHROUGH CHECK TRANS CHECK
D. Is ON during 2 to 3 seconds at ignition but OFF after:
Normal operation. No DTC or malfunction.
821RW261
Diagnostic Check
This test determines if the transmission or its inputs,
outputs, connections, or sensors are failing.
1. Connect the Tech2: GOTHROUGH Te c h 2 O B D I I
CONNECTION.
2. Turn on the ignition but not the engine.3. Push “F2” on Tech2 to see the Diagnostic Trouble
Code (DTC):
4. Do you have a DTC?
YES: write down all code numbers and do the DTC
CHECK
NO: the DTC can not help you finding the problem.
1. GOTHROUGH “CHECK TRANS” CHECK
2. IF it is flashing and the flash is 0.2 seconds ON
and 0.2 seconds OFF, this means that you should
have a DTC stored. Please recheck GOTO
DIAGNOSTIC CHECK and if you find the same
problem, replace the Powertrain Control Module
(PCM).
Normal
C07RW047
Abnormal
C07RW048
7A1–12
TRANSMISSION CONTROL SYSTEM (4L30–E)
“Check Trans” Check
1. Indicator it is ON during 2 to 3 seconds at ignition (or
when the engine is cranked) but it is OFF after the
engine starts. The indicator is working normally
GOTO DIAGNOSTIC CHECK.
821RW261
Normal
C07RW047
2. Indicator it is flashing and the flash is 0.2 seconds ON
and 0.2 seconds OFF always when ignition is on
(engine cranked or not). This means that there is a
malfunction. GOTO DIAGNOSTICAbnormal
C07RW048
3. Indicator it is staying ON always when Ignition is ON.
1. This means that connection between the lamp
and the PCM is shorted to ground.
2. Verify if instrument panel terminal 3 of connector
I–9 is shorted to ground.
3. Verify if the PCM connector J1 (RED) terminal
A14 is shorted to ground.
4. Verify that the instrument panel terminal 15 of
connector I–9 is connected to battery.
5. IF problem solved: GOTO CHECK TRANS
INDICATOR.
NO:Replace Powertrain Control Module (PCM).
4. Indicator it is staying OFF with the ignition ON (engine
OFF).
1. This means that connection between the lamp
and the PCM is shorted to battery or opened.
2. Verify if instrument panel terminal 3 of connector
I–9 is shorted to battery or open.
3. Verify if the PCM connector J1 (RED) terminal
A14 is shorted to battery or open.
4. Verify that the instrument panel terminal 15 of
connector I–9 is connected to battery. If not,
check the fuses and the connections voltage.
5. IF problem solved: GOTO CHECK TRANS
INDICATOR.
NO: Replace Powertrain Control Module (PCM).
7A1–14
TRANSMISSION CONTROL SYSTEM (4L30–E)
2. Connecting the TECH2
901RW180
Legend
(1) PCMCIA Card
(2) RS 232 Loop Back Connector(3) SAE 16/19 Adapter
(4) DLC Cable
(5) Tech2
Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. The Isuzu 98 System PCMCIA card (1) inserts
into the Tech 2 (5).2. Connect the SAE 16/19 adapter (3) to the DLC
cable (4).
3. Connect the DLC cable to the Tech 2 (5)
4. Make sure the vehicle ignition is off.
TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–15
5. Connect the Tech 2 SAE 16/19 adaptor to the
vehicle DLC.
821RW262
821RW263
6. The vehicle ignition turns on.
7. Verify the Tech 2 power up display.
060RW009
NOTE: The RS232 Loop back connector is only to use for
diagnosis of Tech 2 and refer to user guide of the Tech 2.
8. The power up screen is displayed when you
power up the tester with the Isuzu systems
PCMCIA card. Follow the operating procedure
below.
TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–17
Menu
The following table shows, which functions are
used the available equipment versions.
F0: Diagnostic Trouble Codes
F0: Read DTC Info Ordered By Priority
F1: Clear DTC Information
F2: DTC Information
F0: History
F1: MIL SVS or Message Requested
F2: Last Test Failed
F3: Test Failed Since Code Cleared
F4: Not Ran Since Code Cleared
F5: Failed This Ignition
F1: Data Display
3. DVOM
When instructed to use a voltmeter or ohmmeter
within a troubleshooting procedure, use only a high
impedance DVOM (Digital Volt Ohmmeter) such as
J–39200 or equivalent.
7A1–20
TRANSMISSION CONTROL SYSTEM (4L30–E)
821RW263
810RT022
PIN 1 – (Not used)
PIN 2 – J1850 Bus + L line on 2–wire systems, or
single wire (Class 2)
PIN 3 – (Not used)
PIN 4 – Chassis ground pin
PIN 5 – Signal ground pin
PIN 6 – PCM diagnostic enable
PIN 7 – (Not used)
PIN 8 – (Not used)
PIN 9 – Primary UART
PIN 10 – (Not used)
PIN 11 – (Not used)
PIN 12 – ABS diagnostic or CCM diagnostic enable
PIN 13 – SIR diagnostic enable
PIN 14 – (Not used)
PIN 15 – (Not used)
PIN 16 – Battery power from vehicle unswitched (4
AMP MAX.)
Malfunction Indicator Lamp (MIL)
The Malfunction Indicator Lamp (MIL) looks the same as
the MIL you are already familiar with (“CHECK ENGINE”
lamp). However, OBD II requires that it illuminate under a
strict set of guidelines. Basically, the MIL is turned on
when the PCM detects a DTC that will impact the vehicle’s
emissions.
The MIL is under the control of the Diagnostic Executive.
The MIL will be turned on if a component or system which
has an impact on vehicle emissions indicates a
malfunction or fails to pass an emissions–related
diagnostic test. It will stay on until the system or
component passes the same test, for three consecutive
trips, with no emissions–related faults.
Types Of Diagnostic Trouble Codes (DTCs)
The Diagnostic Executive classifies Diagnostic Trouble
Codes (DTCs) into certain categories. Each type has
different requirements to set the code, and the Diagnostic
Executive will only illuminate the Malfunction Indicator
Lamp (MIL) for emissions–related DTCs. DTCs fall into
four categories: A, B, C, and D; only types A and B are
emission–related The following descriptions define these
categories:
TYPE A
Will store the DTC and turn on the MIL (“Check Engine”
lamp) on the first trip in which an emission–related
diagnostic test has run and reported a “test failed” to the
Diagnostic Executive.
TYPE B
Will store the DTC and turn on the MIL on the second
consecutive trip in which an emission–related diagnostic
test has run and reported a “test failed” to the Diagnostic
Executive. After one failure, the type B DTC is “armed,”
or prepared to store a history code and turn on the MIL if
a second failure occurs. One passed test will disarm a
type B DTC. Some special conditions apply to misfire and
fuel trim DTCs. For a type B DTC to store and turn on the
MIL, two ignition cycles are required.
TYPE C
Will store the DTC and turn on a “SERVICE” lamp
(“Check Trans” lamp) on the first trip that a
non–emission–related diagnostic test has run and
reported a “test failed” to the Diagnostic Executive. This
type of DTC will be used in future applications.
TYPE D
Will store a DTC but will not turn on the MIL on the first
trip that a non–emission–related diagnostic test has run
and reported a “test failed” to the Diagnostic Executive.
These codes can be very helpful for vehicle service when
the driver may comment about a condition, but the MIL did
not turn on.
Clear DTC
NOTE: If you clear the DTC (Diagnostic Trouble Codes)
you will not be able to read any codes recorded during the
last occurrence.
TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–21
NOTE: To use the DTC again to identify a problem, you
will need to reproduce the fault or the problem. This may
require a new test drive or just turning the ignition on (this
depends on the nature of the fault).
1. IF you have a Tech2:
1. Connect the Tech2 if it is still not connected
GOTHROUGH Tech2 OBD II CONNECTION.
2. Push “F4” and answer “Yes” to the question “Do
you really want to clear the codes?”
a. When a malfunction remains as it is the Tech2
displays “4L30E CODES NOT CLEARED”. This
means that the problem is still there or that the
recovery was not done. Please GOTO DTC
CHECK.
b. When a malfunction has been repaired and the
recovery is done. The Tech2 displays “4L30E
CODES CLEARED”.
2. IF you have no Tech2:
To clear the DTC, remove Fuse “Stop, A/T CONT”
(C–14, 15A) for at least 10 seconds.
DTC Check
1. Diagnostic Trouble Codes (DTC) have been identified
by Tech2.
2. You have written the list of the DTCs. The order of the
malfunctions has no meanings for this PCM. Usually
only one or two malfunctions should be set for a given
problem.
3. Check directly the DTCs you identified. The DTCs are
sorted by number. Refer to Diagnostic Trouble Code
(DTC) Identification in this section.
PCM Precaution
The PCM can be damaged by:
1. Electrostatic discharge
2. The short circuit of some terminals to voltage or to
ground.
Electrostatic Discharge Damage Description:
1. Electronic components used to control systems are
often designed to carry very low voltage, and are very
susceptible to damage caused by electrostatic
discharge. It is possible for less than 100 volts of
static electricity to cause damage to some electronic
components. By comparison, it takes as much as
4,000 volts for a person to even feel the zap of a static
discharge.2. There are several ways for a person to become
statically charged. The most common methods of
charging are by friction and induction. An example of
charging by friction is a person sliding across a car
seat, in which a charge of as much as 25,000 volts
can build up. Charging by induction occurs when a
person with well insulated shoes stands near a highly
charged object and momentarily touches ground.
Charges for the same polarity are drained off, leaving
the person highly charged with the opposite polarity.
Static charges of either type can cause damage,
therefore, it is important to use care when handling
and testing electronic components.
NOTICE: To prevent possible electrostatic
discharge damage:
1. Do not touch the PCM connector pins or soldered
components on the PCM circuit board.
2. Be sure to follow the guidelines listed below if
servicing any of these electronic components:
3. Do not open the replacement part package until it is
time to install the part.
4. Avoid touching electrical terminals of the part.
5. Before removing the part from its package, ground
the package to a known good ground on the vehicle.
6. Always touch a known good ground before handling
the part. This step should be repeated before
installing the part if the part has been handled while
sliding across the seat, while sitting down from a
standing position or while walking some distance.
Information On PCM
1. The Powertrain Control Module (PCM) is located in
the center console and is the control center of the
electronic transmission control system.
2. The PCM must be maintained at a temperature below
185
F (85C) at all times. This is most essential if the
vehicle is put through a paint baking process. The
PCM will become inoperative if its temperature
exceeds 85
C (185F). Therefore, it is
recommended that the PCM be removed or that
temporary insulation be placed around the PCM
during the time the vehicle is in a paint oven or other
high temperature process.
3. The PCM is designed to process the various inputs
and then respond by sending the appropriate
electrical signals to control transmission upshift,
downshift, shift feel and torque converter clutch
engagement.
4. The PCM constantly interprets information from the
various sensors, and controls the systems that affect
transmission and vehicle performance. By analyzing
operational problems, the PCM is able to perform a
diagnostic function by displaying DTC(s) and aid the
technician in making repairs.
Intermittent Conditions
If the Tech2 displays a diagnostic trouble code as
intermittent, or if after a test drive a DTC does not
reappear though the detection conditions for this DTC are
present, the problem is most likely a faulty electrical
TRANSMISSION CONTROL SYSTEM (4L30–E)7A1–25
DTC P0218 Transmission Fluid Over Temperature
D07RW029
Circuit Description
The Transmission Fluid Temperature (TFT) sensor is a
thermister that controls the signal voltage to the PCM.
The PCM supplies a 5–volt reference to the sensor on
circuit RED/BLK–GRN/RED. When the transmission fluid
is cold, the sensor resistance is high and the PCM will
sense high signal voltage. As the fluid temperature
warms to a normal transmission operating temperature of
100
C (212F), the sensor resistance becomes less and
the voltage decreases to 1.5 to 2.0 volts.
This DTC detects a high transmission temperature for a
long period of time. This is a type “D” DTC.
Conditions For Setting The DTC
No TFT DTCs P0712 or P0713.
TFT is greater than 135C (275F).
All conditions met for 21 seconds.
Action Taken When The DTC Sets
Hot mode TCC Shift Pattern.
The PCM will not illuminate the CHECK TRANS
Lamp.
ATF Lamp ON. (TFT is greater than 145C (293F).)
Disable E–side TCC OFF request.
Conditions For Clearing The DTC
The DTC can be cleared from the PCM history by
using a scan tool.
The DTC will be cleared from history when the vehicle
has achieved 40 warm–up cycles without a failure
reported.
The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled “off”
long enough to power down the PCM.
Diagnostic Aids
Inspect the wiring for poor electrical connections at
the PCM and at the transmission 16–way connector.
Look for possible bent, backed out, deformed, or
damaged terminals. Check for weak terminal tension
as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.
When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.
Check harness routing for a potential short to ground
in circuit RED/BLK–GRN/RED.
Scan tool TFT sensor temperature should rise
steadily to about 100
C (212F), then stabilize.
Check for a “skewed” (mis–scaled) sensor by
comparing the TFT sensor temperature to the
ambient temperature after a vehicle cold soak. A
“skewed” sensor can cause delayed garage shifts or
TCC complaints.
Check for a possible torque converter stator problem.
Verify customer driving habits, trailer towing, etc.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart.
3. This test checks for a “skewed” sensor or shorted
circuit.
4. This test simulates a TFT DTC P0713.