2007 ISUZU KB P190 check transmission fluid

TRANSMISSION CONTROL SYSTEM (AW30–40LE) 7A2-69

Circuit/System Testing DTC P0742
Step Action Value(s) YES NO
1
W as the On-Board Diagnostic (OBD) System Check
performed? 1. Install the scan tool. — Go to
Step 2 Go to OBD
System Check
2 1. Install a scan tool.
2. Turn “ON” the ignition.
3. Review and record scan tool data.
4. Operate the vehicle within scan tool data.

Does a scan tool indicate DTC P0742? — Go to
Step 3 Refer to
Diagnostic Aids
3 Perform the transmission fluid checking procedure.
Refer to checking Transmission Fluid level and
Condition in Automatic Transmission 7A section.
If the problem found, repair or replaces necessary.

W as the problem found? — Go to
Step 8 Go to Step 4
4 Observe the TCC slip speed data on a scan tool.
1. Turn “ON” the ignition with engine “ON”.
2. Road testing the vehicle.
3. The throttle position is more than 20%.
4. The vehicle speed is between 5 km/h (3 mph) and 100 km/h (62 mph).
5. The TCC slip speed is more than 150 rpm at 2nd gear L-up “OFF”.
6. The throttle position is more than 25%.
7. The vehicle speed is between 5 km/h (3 mph) and 80 km/h (50 mph).
8. The T/C revolution difference is less than 100 rpm at 3rd L-up “OFF”.

Above conditions were indicated on a scan tool
display? — Refer to
Diagnostic Aids Go to
Step 5
5 Check the following items.
• Check the L-up solenoid valve. (Refer to Section
7A3)
• L-up solenoid valve stuck “ON” the release position
(Refer to Section 7A4)
• Misaligned or damaged valve body gasket.
• Restricted apply passage.

If the problem found, replaces as necessary.

W as the problem found? — Go to
Step 8 Go to Step 6
6 Check the DTC on a scan tool.

Is DTC found on a scan tool? — Go to
Step 7 Go to Step 8

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ISUZU KB P190 2007

7A2-72 TRANSMISSION CONTROL SYSTEM (AW30–40LE)

Condition For Setting The DTC
All of the following conditions are met.
• Accumulation of feedback error current value is
more than 8A.
• Detect failure twice continuously.
Conditions For Clearing The DTC
• The DTC can be cleared from the TCM 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.
• After more than 1 second has elapsed after the
ignition key has been turned "ON", short between
No.11 and No.4 (ground) of DLC (Data Link
Connector). Then, after 1 second, but within 6
seconds, discontinue shorting.
Action Taken When The DTC Sets
• No L-up control.
• No line pressure reduction control at gear change.
• No squat control.

• No slope control.
• No torque reduction control.
• No line pressure reduction control at garage.
• Line pressure FULL output.
• No shift solenoid functional failure detection.
• No L-up solenoid functional failure detection.
• Become emergency mode.
• Check Trans "ON".
• DTC stored.
• MIL request "ON". (EURO 4 only)
Diagnostic Aids
• Inspect the wiring for poor electrical connection at
the TCM. 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.
• W hen diagnosing for a possible intermittent short
or open condition, move the wiring harness while
observing test equipment for change.

Circuit/System Testing DTC P0746
Step Action Value(s) YES NO
1
W as the On-Board Diagnostic (OBD) System
Check performed? —
Go to Step 2 Go to OBD
System Check
2 1. Install a scan tool.
2. Turn “ON” the ignition.
3. Record a scan tool data.
4. Operate the vehicle within scan tool data.

Does a scan tool indicate DTC P0746? —
Go to Step 3 Refer to
Diagnostic Aids
3 Perform the transmission fluid checking procedure.
Refer to checking Transmission Fluid level and
Condition in Automatic Transmission 7A section.
If the problem found, repair or replace necessary.

W as the problem found? —
Go to Step 9 Go to Step 4

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ISUZU KB P190 2007

7A2-76 TRANSMISSION CONTROL SYSTEM (AW30–40LE)

Circuit/System Testing DTC P0751
Step Action Value(s) YES NO
1
W as the On-Board Diagnostic (OBD) System Check
performed? — Go to
Step 2 Go to OBD
System Check
2 1. Install a scan tool.
2. Turn “ON” the ignition.
3. Review and record scan tool data.
4. Operate the vehicle within scan tool data.

Does a scan tool indicate DTC P0751? — Go to
Step 3 Refer to
Diagnostic Aids
3 Perform the transmission fluid checking procedure.
Refer to checking Transmission Fluid level and
Condition in Automatic Transmission 7A section.
If the problem found, repair or replaces necessary.

W as the problem found? — Go to
Step 8 Go to Step 4
4 Observe the commanded gear and current gear on a
scan tool.
1. Turn “ON” the ignition with engine “ON”.
2. Road testing the vehicle.
3. The throttle position is more than 8%.
4. The vehicle speed is more than 5 km/h (3 mph).

Did the TCM detect 4th gear ratio in case of 1st gear
target, and 3rd gear ratio in case of 2nd gear target?
Above conditions were indicated on a scan tool
display? — Refer to
Diagnostic Aids Go to
Step 5
5 Check the following items.
• Check the shift solenoid valve S1. (Refer to
Section 7A3)
• Shift solenoid valve S1 stuck “OFF” the release
position (Refer to Section 7A4)
• Misaligned or damaged valve body gasket.
• Restricted apply passage.
If the problem found, replaces necessary.

W as the problem found? — Go to
Step 8 Go to Step 6
6 Check the DTC on a scan tool.

Is DTC found on a scan tool? — Go to
Step 7 Go to Step 8
7 Replace the valve body. (Refer to Section 7A4).

Is the action complete? — Go to
Step 8 —

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ISUZU KB P190 2007

7A2-80 TRANSMISSION CONTROL SYSTEM (AW30–40LE)

Circuit/System Testing DTC P0752
Step Action Value(s) YES NO
1
W as the On-Board Diagnostic (OBD) System Check
performed? — Go to
Step 2 Go to OBD
System Check
2 1. Install a scan tool.
2. Turn “ON” the ignition.
3. Review and record scan tool data.
4. Operate the vehicle within scan tool data.

Does a scan tool indicate DTC P0752? — Go to
Step 3 Refer to
Diagnostic Aids
3 Perform the transmission fluid checking procedure.
Refer to checking Transmission Fluid level and
Condition in Automatic Transmission 7A section.
If the problem found, repair or replaces necessary.

W as the problem found? — Go to
Step 8 Go to Step 4
4 Observe the commanded gear and current gear on
the scan tool.
1. Turn “ON” the ignition with engine “ON”.
2. Road testing the vehicle.
3. The throttle position is more than 8%.
4. The vehicle speed is more than 5 km/h (3 mph).

Did the TCM detect 2nd gear ratio in case of 3rd gear
target? Above conditions were indicated on the scan
tool display? — Refer to
Diagnostic Aids Go to
Step 5
5 Check the following items.
• Check the shift solenoid valve S1. (Refer to
Section 7A3)
• Shift solenoid valve S1 stuck “ON” the release
position (Refer to Section 7A4)
• Misaligned or damaged valve body gasket.
• Restricted apply passage.
If the problem found, replaces necessary.

W as the problem found? — Go to
Step 8 Go to Step 6
6 Check the DTC on a scan tool.

Is DTC found on a scan tool? — Go to
Step 7 Go to Step 8
7 Replace the valve body. (Refer to Section 7A4).

Is the action complete? — Go to
Step 8 —

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ISUZU KB P190 2007

7A2-84 TRANSMISSION CONTROL SYSTEM (AW30–40LE)

Circuit/System Testing DTC P0756
Step Action Value(s) YES NO
1
W as the On-Board Diagnostic (OBD) System Check
performed? — Go to
Step 2 Go to OBD
System Check
2 1. Install the scan tool.
2. Turn “ON” the ignition.
3. Review and record scan tool data.
4. Operate the vehicle within scan tool data.

Does a scan tool indicate DTC P0756? — Go to
Step 3 Refer to
Diagnostic Aids
3 Perform the transmission fluid checking procedure.
Refer to checking Transmission Fluid level and
Condition in Automatic Transmission 7A section.
If the problem found, repair or replace necessary.

W as the problem found? — Go to
Step 8 Go to Step 4
4 Observe the commanded gear and current gear on
the scan tool.
1. Turn “ON” the ignition with engine “ON”.
2. Road testing the vehicle.
3. The throttle position is more than 8%.
4. The vehicle speed is more than 5 km/h (3 mph).

Did the TCM detect 1st gear ratio in case of 2nd gear
target, and 4th gear ratio in case of 3rd gear target?
Above conditions were indicated on a scan tool
display? — Refer to
Diagnostic Aids Go to
Step 5
5 Check the following items.
• Check the shift solenoid valve S2. (Refer to
Section 7A3)
• Shift solenoid valve S2 stuck “OFF” the release
position (Refer to Section 7A4)
• Misaligned or damaged valve body gasket.
• Restricted apply passage.
If the problem found, replaces necessary.

W as the problem found? — Go to
Step 8 Go to Step 6
6 Check the DTC on a scan tool.

Is DTC found on a scan tool? — Go to
Step 7 Go to Step 8
7 Replace the valve body. (Refer to Section 7A4).

Is the action complete? — Go to
Step 8 —

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ISUZU KB P190 2007

7A2-88 TRANSMISSION CONTROL SYSTEM (AW30–40LE)

Circuit/System Testing DTC P0757
Step Action Value(s) YES NO
1
W as the On-Board Diagnostic (OBD) System Check
performed? — Go to
Step 2 Go to OBD
System Check
2 1. Install a scan tool.
2. Turn “ON” the ignition.
3. Review and record scan tool data.
4. Operate the vehicle within scan tool data.

Does a scan tool indicate DTC P0757? — Go to
Step 3 Refer to
Diagnostic Aids
3 Perform the transmission fluid checking procedure.
Refer to checking Transmission Fluid level and
Condition in Automatic Transmission 7A section.
If the problem found, repair or replace necessary.

W as the problem found? — Go to
Step 8 Go to Step 4
4 Observe the commanded gear and current gear on
the scan tool.
1. Turn “ON” the ignition with engine “ON”.
2. Road testing the vehicle.
3. The throttle position is more than 8%.
4. The vehicle speed is more than 5 km/h (3 mph).

Did the TCM detect 2nd gear ratio in case of 1st gear
target, and 3rd gear ratio in case of 4th gear target?
Above conditions were indicated on the scan tool
display? — Refer to
Diagnostic Aids Go to
Step 5
5 Check the following items.
• Check the shift solenoid valve S2. (Refer to
Section 7A3)
• Shift solenoid valve S2 stuck “ON” the release
position (Refer to Section 7A4)
• Misaligned or damaged valve body gasket.
• Restricted apply passage.
If the problem found, replaces necessary.

W as the problem found? — Go to
Step 8 Go to Step 6
6 Check the DTC on a scan tool.

Is DTC found on a scan tool? — Go to
Step 7 Go to Step 8
7 Replace the valve body. (Refer to Section 7A4).

Is the action complete? — Go to
Step 8 —

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ISUZU KB P190 2007

ON-VEHICLE SERVICE (AW30–40LE) 7A3-9
Manual Shifting Test
NOTE: W ith this test, it can be determined whether the
trouble lies within the electrical circuit or is a mechanical
problem in the transmission.
1. Disconnect TCM connector
2. Inspect manual driving operation
Check that the relation of the position between
select lever and gear corresponds to the following
table.
If any abnormality is found in the above test, do
perform the stall, time lag or gear shift tests.







RTW 77ASH002901
3. Connect TCM connector
W ith the engine off, connect the TCM connector.


Stall Test





RTW 67ALH000101
The object of this test is to check the overall
performance of the transmission and engine b
y
measuring the maximum engine speeds at the “D" and
“R" positions.
NOTE:
1. Perform the test at normal operating fluid
temperature (50 – 80 °C or 122 – 176 °F).
2. Do not continuously run this test longer than 5 seconds.





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ISUZU KB P190 2007

ON-VEHICLE SERVICE (AW30–40LE) 7A3-11
Measure Time Lag
1. Fully apply the parking brake.
2. Start the engine. Check idling speed (A/C OFF).
3. Operate the select lever from “N" to “D" position.
Using a stopwatch, measure the time it takes from
shifting the lever until the shock is felt.
Time lag: Less than 0.7 seconds
4. In same manner, measure the time lag for “N" →
“R".
Time lag: Less than 1.2 seconds
Evaluation
1. If “N" → “D" time lag is longer than specified:
• Line pressure too low
• Forward clutch malfunction
• No.2 one-way clutch not operating properly
2. If “N" → “R" time lag is longer than specified:
• Line pressure too low
• Direct clutch malfunction
• First and Reverse brake malfunction
3. If both time lag is longer than specified:
• Line pressure too low

Hydraulic Test






RTW 67ALH000201
Preparation
1. W arm up the transmission fluid.
2. Remove the transmission case test plug and mount the hydraulic pressure gauge.
Oil pressure gauge: 5-8840-0093-0
NOTE: Perform the test at normal operating fluid
temperature (50 – 80 °C or 122 – 176 °F).




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ISUZU KB P190 2007