Isuzu N-Series. Manual - part 904

Transmission Control System (Smoother) 7A-71

P0605 (Flash Code 33)

Description
This diagnostic applies to internal microprocessor
integrity conditions within the transmission control
module (TCM).
Condition for Setting the DTC
Either of following condition is met:

• The TCM detects a malfunction in its internal

Random Access Memory (RAM).

• The TCM detects a calculated checksum does not

agree with the TCM internal registered checksum.

Action Taken When the DTC Sets

• The TCM illuminates the transmission warning

lamp when the diagnostic runs and fails.

• The TCM continuously sounds buzzer when the

diagnostic runs and fails.

• The TCM inhibits transmission control.

Condition for Clearing the DTC

• The TCM turns OFF the transmission warning

lamp when the diagnostic runs and does not fail.

• The TCM stops the buzzer when the diagnostic

runs and does not fail.

• A current DTC clears when the diagnostic runs and

does not fail.

• A history DTC clears with the Tech 2 or reset

switch operation.

DTC P0605 (Flash Code 33)

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Transmission Controls?

—

Go to Step 2

Go to Diagnostic

System Check -

Transmission

Controls

1. Install the Tech 2.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the Diagnostic Trouble Code (DTC)

Information with the Tech 2.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Step 4

Important:
Replacement TCM must be programmed and
learned.
Replace the TCM. Refer to Transmission Control
Module (TCM) Replacement in this section.

Did you complete the replacement?

—

Go to Step 4

—

1. Clear the DTCs with the Tech 2.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 5

Observe the DTC Information with the Tech 2.

Are there any DTCs that you have not diagnosed?

—

Go to Diagnostic

Trouble Code (DTC)

List

System OK

7A-72 Transmission Control System (Smoother)

P0613 (Flash Code 33)

Description
This diagnostic applies to internal microprocessor
integrity conditions within the transmission control
module (TCM).
Condition for Setting the DTC

• The TCM detects a faulty learning data in the

Electronically Erasable Programmable Read Only
Memory (EEPROM).

Action Taken When the DTC Sets

• The TCM illuminates the transmission warning

lamp when the diagnostic runs and fails.

• The TCM continuously sounds buzzer when the

diagnostic runs and fails.

• The TCM inhibits gear select & shift position

learning and half-clutch learning.

Condition for Clearing the DTC

• The TCM turns OFF the transmission warning

lamp when the diagnostic runs and does not fail.

• The TCM stops the buzzer when the diagnostic

runs and does not fail.

• A current DTC clears when the diagnostic runs and

does not fail.

• A history DTC clears when the diagnostic runs and

does not fail.

DTC P0613 (Flash Code 33)

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Transmission Controls?

—

Go to Step 2

Go to Diagnostic

System Check -

Transmission

Controls

1. Install the Tech 2.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Monitor the Diagnostic Trouble Code (DTC)

Information with the Tech 2.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Step 4

Important:
Replacement TCM must be programmed and
learned.
Replace the TCM. Refer to Transmission Control
Module (TCM) Replacement in this section.

Did you complete the replacement?

—

Go to Step 4

—

1. Clear the DTCs with the Tech 2.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 5

Observe the DTC Information with the Tech 2.

Are there any DTCs that you have not diagnosed?

—

Go to Diagnostic

Trouble Code (DTC)

List

System OK

Transmission Control System (Smoother) 7A-73

P0710 (Flash Code 21)

Circuit Description
The transmission fluid temperature (TFT) sensor is
located on the oil pump assembly and soaked in the
transmission fluid. The TFT sensor is a variable resistor.
The TFT sensor has a signal circuit and a low reference
circuit. The transmission control module (TCM) supplies
5 volts to the TFT sensor signal circuit and a ground for
the TFT sensor low reference circuit. When the TFT is
cold, the sensor resistance is high. When the TFT
increases, the sensor resistance decreases. With high
sensor resistance, the TCM detects a high voltage on
the TFT sensor signal circuit. With lower sensor
resistance, the TCM detects a lower voltage on the TFT
sensor signal circuit. If the TCM detects an excessively
low or high TFT signal voltage, this DTC will set.
Condition for Running the DTC

• The ignition switch is ON.
• The ignition voltage is more than 20 volts.
• The emergency switch is OFF.

Condition for Setting the DTC

• The TCM detects that the TFT sensor signal

voltage is less than 0.1 volts (more than 165

°C

[329

°F]) or more than 4.9 volts (less than −50°C [−

°F]).

Action Taken When the DTC Sets

• The TCM illuminates the transmission warning

lamp when the diagnostic runs and fails.

• The TCM uses a TFT substitution of 50

°C (122°F)

for transmission control.

• The TCM inhibits gear select & shift position

learning and half-clutch learning.

Condition for Clearing the DTC

• The TCM turns OFF the transmission warning

lamp when the diagnostic runs and does not fail.

• A current DTC clears when the diagnostic runs and

does not fail.

• A history DTC clears when the diagnostic runs and

does not fail.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

• Use the Temperature vs. Resistance table to test

the TFT sensor at various temperature levels to
evaluate the possibility of a skewed sensor. A
skewed sensor could result in poor driveability
concerns.

• If this DTC is present, harsh garage shift appears

when shifted from N to D or N to R.

DTC P0710 (Flash Code 21)

Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or Transmission Control
Module (TCM) Connector End Views

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Transmission Controls?

—

Go to Step 2

Go to Diagnostic

System Check -

Transmission

Controls

1. Install the Tech 2.
2. Turn OFF the ignition for 30 seconds.
3. Turn ON the ignition, with the engine OFF.
4. Observe the Transmission Fluid Temperature

(TFT) Sensor parameter with the Tech 2.

Notice:
If the TFT sensor signal voltage is more than 4.9
volts, the TFT Sensor parameter on the Tech 2
indicates a default value when the ignition has been
turned ON for longer than 5 seconds.

Does the TFT Sensor parameter ever exceed the
specified value within 5 seconds after the ignition
switch is ON?

4.9 volts

Go to Step 4

Go to Step 3

Notice:
If the TFT sensor signal is less than 0.1 volts, the
TFT Sensor parameter on the Tech 2 indicates a
default value when the ignition has been turned ON
for longer than 5 seconds.

Does the TFT Sensor parameter ever fall below the
specified value within 5 seconds after the ignition
switch is ON?

0.1 volts

Go to Step 14

Go to Diagnostic

Aids

7A-74 Transmission Control System (Smoother)

1. Turn OFF the ignition.
2. Disconnect the in-line harness connector (J-

237) near the starter motor.

3. Connect a DMM between the signal circuit of

the TFT sensor harness (pin 2 of J-237 female
connector) and a known good ground.

4. Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

5.5 volts

Go to Step 5

Go to Step 6

Important:
The TFT sensor may be damaged if the sensor
signal circuit is shorted to a voltage source.

1. Test the signal circuit between the

transmission control module (TCM) (pin 6 of B-
427 connector) and the in-line connector (pin 2
of J-237 connector) for a short to battery or
ignition voltage.

2. Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 19

Go to Step 18

1. Turn OFF the ignition.
2. Connect a test lamp between the signal circuit

of the TFT sensor harness (pin 2 of J-237
female connector) and a known good ground.

3. Connect a DMM between the probe of the test

lamp and a known good ground.

4. Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

4.5 volts

Go to Step 10

Go to Step 7

1. Turn OFF the ignition.
2. Connect a DMM across the signal circuit and

low reference circuit of the TFT sensor
harness (pins 2 and 4 of J-237 female
connector).

3. Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

4.5 volts

Go to Step 11

Go to Step 8

1. Test the signal circuit between the TCM (pin 6

of B-427 connector) and the in-line harness
connector (pin 2 of J-237 connector) for an
open circuit or high resistance.

2. Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 19

Go to Step 9

1. Test the low reference circuit between the

TCM (pin 12 of J-237 connector) and the in-
line harness connector (pin 4 of J-237
connector) for an open circuit or high
resistance.

2. Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 19

Go to Step 12

1. Test the signal circuit between the TCM (pin 6

of B-427 connector) and the in-line harness
connector (pin 2 of J-237 connector) for a short
to any 5 volts reference circuit.

2. Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 19

Go to Step 18

Step

Action

Value(s)

Yes

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