Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual — part 1757

DIAGNOSIS 7A2-79

DTC P1750 (Flash Code 51) Low & Reverse Brake Fail-safe Valve Failure

Low & Reverse Brake Fail Valve (B)

Control Valve Upper Body

Low & Reverse Brake Fail Valve (A)

Control Valve Lower Body

Setting Condition:

•

When the oil pressure generated and low & reverse brake pressure switch operates off/on twice, the TCM

detected an operation failure of the low & reverse brake fail-safe valve in D, 3, 2, L range.

Fail Safe:

•

When the vehicle is running, the gear position selected at the trouble detection is held and the lock-up is

inhibited.

•

After the vehicle stopped, all solenoid operations stop (OFF) and the gear is fixed to the 3rd.

Possible Cause:

•

Stick of low & reverse brake fail-safe valve.

•

Low & reverse brake pressure switch does not turn on.

•

Short circuit to ground of harness low & reverse brake pressure switch.

•

Poor connection of each connector of harness in low & reverse brake pressure switch.

7A2-80 DIAGNOSIS

Step

Action

Yes

No

1

Turn the key switch on and check the DTC. Is only the DTC for
low & reverse brake fail-safe valve failure outputted?

Go to Step 2

Go to Other DTC

Section

2

Clear the DTC from the memory. Turn the key switch off once,
and then start the engine. Does the CHECK TRANS blink
when the D range is selected and about 10 seconds elapsed?

Go to Other DTC

Section

Go to Step 3

3

Run the vehicle, shift the gear from 1st to 4th, stop the vehicle,
and again shift the gear from 1st to 4th. Does the CHECK
TRANS blink at this time?

Go to Step 4

The low & reverse

brake fail-safe valve

may be faulty

temporarily.

Go to step 5

4

Turn the key switch on and check the DTC. Is only the DTC for
the low & reverse brake fail-safe valve failure outputted?

Repair or replace the

control valve.

Go to Step 5

Go to Other DTC

Section

5

Clear the DTC from the memory and perform the work after
repair. Is the same DTC code outputted again in the
subsequent DTC check?

Replace the TCM

Go to Step 6

6

Are the other DTCs outputted?

Go to Other DTC

Section

Action is completed

DIAGNOSIS 7A2-81

DTC P1755 (Flash Code 52) 2-4 Brake Fail-safe Valve Failure

Control Valve Upper Body

2-4 Brake Fail Valve (B)

Control Valve Lower Body

2-4 Brake Fail Valve (A)

Setting Condition:

•

When the oil pressure generated and 2-4 brake pressure switch operates off/on twice, the TCM detected an

operation failure of the low & reverse brake fail-safe valve in D, 3, 2, L range.

Fail Safe:

•

When the vehicle is running, the gear position selected at the trouble detection is held and the lock-up is

inhibited.

•

After the vehicle stopped, all solenoid operations stop (OFF) and the gear is fixed to the 3rd.

Possible Cause:

•

Stick of 2-4 brake fail-safe valve.

•

2-4 brake pressure switch does not turn on.

•

Short to ground of harness 2-4 brake pressure switch.

•

Faulty fitting of each connector of harness in 2-4 brake pressure switch.

7A2-82 DIAGNOSIS

Step

Action

Yes

No

1

Turn the key switch on and check the DTC. Is only the DTC for
2-4 brake fail-safe valve failure outputted?

Go to Step 2

Go to Other DTC

Section

2

Clear the DTC from the memory. Turn the key switch off once,
and then start the engine. Does the CHECK TRANS blink when
the D range is selected and about 10 seconds elapsed?

Go to Other DTC

Section

Go to Step 3

3

Run the vehicle, shift the gear from 1st to 4th, stop the vehicle,
and again shift the gear from 1st to 4th. Does the CHECK
TRANS blink at this time?

Go to Step 4

The 2-4 brake fail-safe

valve may be faulty

temporarily.

Go to step 5

4

Turn the key switch on and check the DTC. Is only the DTC for
the 2-4 brake fail-safe valve failure outputted?

Repair or replace the

control valve.

Go to Step 5

Go to Other DTC

Section

5

Clear the DTC from the memory and perform the work after
repair. Is the same DTC code outputted again in the
subsequent DTC check?

Replace the TCM

Go to Step 6

6

Are the other DTCs outputted?

Go to Other DTC

Section

Action is completed