Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual — part 1863

7A2-68 DIAGNOSIS

Step

Action

Yes

No

8

Connect the Tech 2, and with the key switch in OFF position, short
the terminals 11 and 12 on the vehicle harness side. Does the
indication of the low & reverse brake pressure switch on the Tech 2
becomes on when the key switch is turned on?

Go to Step 9

Repair the harness

or connector.

Go to Step 12

9

Check if the trouble is caused by a poor connection of terminal
assembly connector.
With the key switch in OFF position, is the connection condition of
the connector and harness correct?

Go to Step 10

Repair the harness

or connector.

Go to Step 12

10 Remove the oil pan. Is the continuity correct between terminal

assembly terminal 12 and low & reverse brake pressure switch
connector?

12

Go to Step 11

Repair the harness

or connector.

Go to Step 12

11 Is the result OK when the oil pan is removed and the low & reverse

brake pressure switch is checked? Refer the ON VEHICLE
SERVICE SECTION in this manual for the procedure.

Repair the control

valve.

Go to Step 12

Replace pressure

switch.

Go to Step 12

12 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 13

13 Are the other DTCs outputted?

Go to Other DTC

Section

Action is completed

DIAGNOSIS 7A2-69

DTC P1858 (Flash Code 27) 2-4 Brake Pressure Switch Failure

Control Valve

TCM

B1

B12

B20

RED/YEL

WHT/BLK

2-4 Brake Pressure SW

Terminal

Assembly

YEL

E54

(7)

(12)

(1)

H23

(12)

(10)

C95

(1)

(12)

(20)

RED/YEL

YEL

WHT/BLK

L&R Brake Pressure SW

High Clutch Pressure SW

H22

(8)

Pre-setting Condition:

•

No gear shifting.

•

No Check Trans indicator lamp.

•

No system voltage failure.

•

No inhibitor switch failure.

•

2-4 brake duty solenoid 0 or 100 %.

•

ATF temperature more than 60

°

C.

•

ATF input voltage more than 0.1V.

•

Engine speed more than 500 rpm.

7A2-70 DIAGNOSIS

Setting Condition:

•

During the running, the 2-4 brake pressure switch does not turn on though hydraulic pressure is supposed to be

generated in 2-4 brake.

(All pre-setting conditions are met for 2.5 seconds, 2-4 brake pressure switch off, high clutch pressure switch on

and gear ratio more than 0.65 or less than 0.74 with 4th gear in D range.)

Or

•

During the running, the 2-4 brake switch does not turn off though no hydraulic pressure is supposed to be

generated in the 2-4 brake.

(All pre-setting conditions are met for 2.5 seconds, 2-4 brake pressure switch on in D or N range.)

Fail Safe:

•

No fail safe function

Possible Cause:

•

2-4 brake duty solenoid malfunction.

•

2-4 brake pressure switch wire open circuit or short circuit.

•

Open circuit, short circuit to battery or short circuit to ground between 2-4 brake pressure switch terminal 7 and

TCM terminal B1 (C95).

•

2-4 brake hydraulic circuit malfunction in the control valve.

•

Poor connection of each connector.

Reference:

When the 2-4 brake pressure switch is operated, following signal is outputted.

Measurement terminal: B1 (C95) and B22 (C95)

-At other than 2nd or 4th gear: More than 10V

-At 2nd or 4th gear: Less than 1V

DIAGNOSIS 7A2-71

Step

Action

Yes

No

1

Clear the DTC from the memory once.
Was the action complete?

Go to Step 2

Refer DTC clear

method in this

manual.

2

Turn the ignition switch off once, then restart the engine and in D
range. When about 10 seconds elapsed, does the CHECK TRANS
lamp blink?

Go to Step 3

Go to Step 7

3

Is the DTC P0758 (32) 2-4 Brake Duty Solenoid Failure stored?

Go to P0758 (32)

Section

Go to Step 4

4

Connect the Tech 2 and select the item for 2-4 brake pressure
switch. Is the indication of 2-4 brake pressure switch turned off when
the terminal assembly connector is disconnected?

Go to Step 5

Repair the harness

or connector.

Go to Step 12

5

Turn the key switch off and disconnect the terminal assembly
connector. Are the pins correct?

Go to Step 6

Repair the

connector or pin.

Go to Step 12

6

Remove the oil pan. Is the continuity correct between terminal
assembly teminal 7 and 2-4 brake pressure switch connector?

7

Repair the harness

or connector.

Go to Step 12

Replace pressure

switch.

Go to Step 12

7

Start the engine and shift to 4th gear in the D range. When about 10
seconds elapsed, does the CHECK TRANS lamp blink?

Go to Step 8

Go to P0758 (32)

Section