Isuzu KB P190. Manual - part 1083

7A2-48   TRANSMISSION CONTROL SYSTEM (JR405E)

4

Intermittently jump the signal circuit (pin 1 of E-30)
with a test lamp that is connected to a known good
ground while observing the AT Output Speed or
Vehicle Speed parameter with a scan tool.

Does the scan tool indicate any AT output speed or
vehicle speed when the circuit is intermittently
pulled to ground?

—

Go to Step 5 

Go to Step 8

5

Connect a test lamp between the ignition voltage
feed circuit and the low reference circuit (pins 2 and
3 of E-30).

Does the test lamp illuminate?

—

Go to Step 9 

Go to Step 7

6

Repair the open circuit or high resistance between
the TCM (15A) fuse and the OSS sensor (pin 2 of
E-30).

Did you complete the repair?

—

Go to Step 14

—

7

Repair the open circuit or high resistance on the
low reference circuit between the OSS sensor (pin
3 of E-30) and the engine ground terminal (E-10).
Clean or tighten ground as necessary.

Did you complete the repair?

—

Go to Step 14

—

8

1.

Test the signal circuit between the TCM (pin
13 of C-95) and the OSS sensor (pin 1 of E-
30) for the following conditions:

• An open circuit

• A short to ground

• A short to the low reference

• A short to battery or ignition voltage

• High resistance

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14 

Go to Step 10

9

1.

Inspect for an intermittent and for poor
connections at the harness connector of the
OSS sensor (pin 1, 2 and 3 of E-30).

2.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14 

Go to Step 11

10

1.

Turn OFF the ignition.

2.

Disconnect the TCM harness connector.

3.

Inspect for an intermittent and for a poor
connection at the harness connector of the
TCM (pin 13 of C-95).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14 

Go to Step 13

Step

Action

Value(s)

Yes

No

TRANSMISSION CONTROL SYSTEM (JR405E)   7A2-49

11

1.

Inspect the OSS sensor and the parking gear
for the following conditions:

• Physical damage of sensor

• Loose or improper installation of sensor

• Excessive air gap

• Foreign material passing between sensor

and parking gear 

• Physical damage of parking gear 

2.

Repair or replace as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 12

12

Replace the OSS sensor. Refer to repair
instructions (On-Vehicle Service).

Did you complete the replacement?

—

Go to Step 14

—

13

Important: Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.

Did you complete the replacement?

—

Go to Step 14

—

14

1.

Reconnect all previously disconnected
components or harness connector(s).

2.

Clear the DTCs with a scan tool.

3.

Turn OFF the ignition for 30 seconds. 

4.

Drive the vehicle while observing the Vehicle
Speed parameter with a scan tool.

Does the scan tool indicate correct vehicle speed?

—

Go to Step 15

Go to Step 3

15

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List 

System OK

Step

Action

Value(s)

Yes

No

7A2-50   TRANSMISSION CONTROL SYSTEM (JR405E)

DTC P0727 (Flash Code 13)

Circuit Description

The engine speed signal to the TCM is sent from the
engine control module (ECM) via a signal circuit based
on inputs from the crankshaft position (CKP) sensor
and camshaft position (CMP) sensor. If the TCM
detects no engine speed signal from the ECM during
the vehicle running, this DTC will set.

Condition for Running the DTC

• The ignition switch is ON. 

• The vehicle speed is more than 40 km/h (24 MPH).

Condition for Setting the DTC

• The TCM detects that the engine speed signal

pulses from the ECM are not being received for 2
seconds.

Action Taken When the DTC Sets

• The TCM blinks the Check Trans lamp when the

diagnostic runs and fails.

• The TCM inhibits lock up control.

Condition for Clearing the DTC

• The TCM turns OFF the Check Trans lamp when

the diagnostic runs and does not fail.

• A current 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.

Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views

Circuit/ System Testing DTC P0727

Step

Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check -
Transmission Controls?

—

Go to Step 2

Go to Diagnostic 

System Check -

Transmission 

Controls

2

1.

Install a scan tool.

2.

Turn OFF the ignition for 30 seconds. 

3.

Start the engine. If the engine does not start,
crank over the engine for 10 seconds.

4.

Monitor the ENGINE DTC Information with a
scan tool.

Is DTC P0335, P0336, P0340 or P0341 set?

—

Go to Applicable 

DTC in engine 
control section

Go to Step 3

3

Observe the Engine Speed parameter in the
transmission data display with a scan tool.

Does the scan tool indicate correct engine speed?

—

Go to Diagnostic 

Aids

Go to Step 4

4

1.

Turn OFF the ignition. 

2.

Disconnect the engine control module (ECM)
harness connector.

3.

Turn ON the ignition, with the engine OFF.

4.

Intermittently jump the signal circuit (pin 33 of
C-58) with a test lamp that is connected to a
known good ground while observing the
Engine Speed parameter with a scan tool.

Does the scan tool indicate any engine speed when
the circuit is intermittently pulled to ground?

—

Go to Step 7

Go to Step 5

TRANSMISSION CONTROL SYSTEM (JR405E)   7A2-51

5

1.

Test the signal circuit between the ECM (33 of
C-58) and the TCM (7 of C-94) for the
following conditions:

• An open circuit

• A short to ground

• A short to battery or ignition voltage

• High resistance

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 10

Go to Step 6

6

1.

Turn OFF the ignition.

2.

Inspect for an intermittent and for a poor
connection at the harness connector of the
TCM (pin 7 of C-94).

3.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 10

Go to Step 8

7

1.

Turn OFF the ignition.

2.

Inspect for an intermittent and for a poor
connection at the harness connector of the
ECM (pin 33 of C-58).

3.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 10

Go to Step 9

8

Important: Replacement TCM must be
programmed.
Replace the TCM. Refer to TCM Replacement.

Did you complete the replacement?

—

Go to Step 10

—

9

Important: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.

Did you complete the replacement?

—

Go to Step 10

—

10

1.

Reconnect all previously disconnected
harness connector(s).

2.

Clear the DTCs with a scan tool.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine. 

5.

Observe the Engine Speed parameter with a
scan tool.

Does the scan tool indicate correct engine speed?

—

Go to Step 11

Go to Step 4

11

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

No