Isuzu KB P190. Service manual - part 304

6E-182 Engine Control System (4JH1)

Step Action

Value(s)

Yes

Replace the Stop (15A) fuse (C-15). If the fuse
continues to open, repair the short to ground on one
of the circuits that is fed by the Stop (15A) fuse (C-
15) or replace the shorted attached component fed
by the Stop (15A) fuse (C-15).
Did you complete the repair?



Go to Step 22



1. Turn OFF the ignition.
2. Disconnect the brake pedal switch harness

connector.

3. Connect a test lamp between the voltage feed

circuit of the brake pedal 1 switch harness (pin 1
of C-44 connector) and a known good ground.

Does the test lamp illuminate?



Go to Step 7

Go to Step 8

1. Turn ON the ignition, with the engine OFF.
2. Observe the Brake Pedal 1 Switch parameter

with the scan tool while momentarily jumping 3-
amp fused jumper wire across the brake pedal 1
switch harness connector between pins 1 and 2
of the C-44 connector.

Does the scan tool indicate Applied when the circuit
is jumpered and Released when the circuit is not
jumpered?



Go to Step 18

Go to Step 9

Repair the open circuit or high resistance on the
voltage feed circuit between the Stop (15A) fuse (C-
15) and the brake pedal 1 switch (pin 1 of C-44
connector).
Did you complete the repair?



Go to Step 22



1. Test the brake pedal 1 switch signal circuit

between the ECM (pin 30 of C-56 connector) and
the brake pedal 1 switch (pin 2 of C-44
connector) for the following conditions:

•  An open circuit
•  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 22

Go to Step 19

Observe the Brake Pedal 2 Switch parameter with
the scan tool while fully depressing and releasing the
brake pedal.
Does the scan tool indicate Applied when the brake
pedal is applied and Released when the brake pedal
is released?



Go to Diagnostic

Aids

Go to Step 11

1. Check to ensure the brake pedal switch is

adjusted correctly. The plunger should be all the
way in when the pedal is released, yet should not
impede with the brake pedal full upward travel.

2. Adjust the brake pedal switch as necessary.
Did you find and correct the condition?



Go to Step 22

Go to Step 12

1. Turn OFF the ignition.
2. Inspect the ECM (10A) fuse (EB-4) in the engine

room fuse block.

Is the ECM (10A) fuse (EB-4) open?



Go to Step 13

Go to Step 14

Engine Control System (4JH1) 6E-183

Step Action

Value(s)

Yes

Replace the ECM (10A) fuse (EB-4). If the fuse
continues to open, repair the short to ground on one
of the circuits that is fed by the ECM (10A) fuse (EB-
4) or replace the shorted attached component fed by
the ECM (10A) fuse (EB-4).
Did you complete the repair?



Go to Step 22



1. Turn OFF the ignition.
2. Disconnect the brake pedal switch harness

connector.

3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the voltage feed

circuit of the brake pedal 2 switch harness (pin 3
of C-44 connector) and a known good ground.

Does the test lamp illuminate?



Go to Step 15

Go to Step 16

1. Turn ON the ignition, with the engine OFF.
2. Observe the Brake Pedal 2 Switch parameter

with the scan tool while momentarily jumping 3-
amp fused jumper wire across the brake pedal 2
switch harness connector between pins 3 and 4
of the C-44 connector.

Does the scan tool indicate Applied when the circuit
is jumpered and Released when the circuit is not
jumpered?



Go to Step 18

Go to Step 17

Repair the open circuit or high resistance on the
voltage feed circuit between the ECM (10A) fuse
(EB-4) and the brake pedal 2 switch (pin 3 of C-44
connector).
Did you complete the repair?



Go to Step 22



1. Test the brake pedal 2 switch signal circuit

between the ECM (pin 65 of C-56 connector) and
the brake pedal 2 switch (pin 4 of C-44
connector) for the following conditions:

• An open circuit
• 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 22

Go to Step 19

1. Turn OFF the ignition.
2. Disconnect the brake pedal switch harness

connector.

3. Inspect for an intermittent and for poor

connections at the harness connector of the
brake pedal switch (pins 1, 2, 3 and 4 of C-44
connector).

4. Repair the connection(s) as necessary.
Did you find and correct the condition?



Go to Step 22

Go to Step 20

1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for poor

connections on the brake switch circuits at the
harness connector of the ECM (pins 30 and 65 of
C-56 connector).

4. Repair the connection(s) as necessary.
Did you find and correct the condition?



Go to Step 22

Go to Step 21

Replace brake pedal switch. Refer to Brake Switch
Replacement in this section.
Did you complete the replacement?



Go to Step 22



6E-184 Engine Control System (4JH1)

Step Action

Value(s)

Yes

Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement?



Go to Step 22



1. Reconnect all previously disconnected fuse or

harness connector(s).

2.  Clear the DTCs with the scan tool.
3.  Turn ON the ignition, with the engine OFF.
4.  Observe the Brake Pedal 1 Switch and the Brake

Pedal 2 Switch with the scan tool while fully
depressing and releasing the brake pedal.

Does the scan tool indicate Applied when the brake
pedal is applied and Released when the brake pedal
is released?



Go to Step 23

Go to Step 2

Observe the DTC Information with the scan tool.
Are there any DTCs that you have not diagnosed?



Go to Diagnostic

Trouble Code (DTC)

List System

Engine Control System (4JH1) 6E-185

DTC P0704 (Symptom Code 6) (Flash Code 57)

Circuit Description
The clutch pedal switch is installed on the clutch pedal
bracket. The clutch pedal switch is a normally closed
type switch. When the clutch pedal is pressed, the
clutch pedal switch signal to the engine control module
(ECM) is stopped (low voltage). If the ECM detects the
clutch pedal switch signal is not change during a
predetermined vehicle speed range, this DTC will set.
This DTC will only run once per ignition cycle within the
enabling condition.
Condition for Running the DTC

• The ignition switch is ON.

Condition for Setting the DTC

• The ECM detects that the clutch pedal switch

signal does not change during the vehicle speed
changes between 1.5 km/h (1 MPH) and 80 km/h
(50 MPH). This DTC will only run once per ignition
cycle within the enabling condition.

Action Taken When the DTC Sets

• The ECM illuminates the malfunction indicator

lamp (MIL) when the diagnostic runs and fails.

Condition for Clearing the MIL/DTC

• The ECM turns OFF the MIL when the diagnostic

runs and does not fail.

• A history DTC clears after 40 consecutive driving

cycles without a fault. Or clear with the scan tool

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

• Misadjusted clutch pedal switch will cause this

DTC to set.

DTC P0704 (Symptom Code 6) (Flash Code 57)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views

Step Action

Value(s)

Yes

Did you perform the Diagnostic System Check-
Engine Controls?



Go to Step 2

Go to Diagnostic

System Check-

Engine Controls

1.  Install the scan tool.
2.  Turn ON the ignition, with the engine OFF.
3.  Observe the Clutch Pedal Switch parameter with

the scan tool while fully depressing and releasing
the clutch pedal.

Does the scan tool indicate Applied when the clutch
pedal is applied and Released when the clutch pedal
is released?



Go to Diagnostic

Aids

Go to Step 3

1. Check to ensure the clutch pedal switch is

adjusted correctly. The plunger should be all the
way in when the pedal is released, yet should not
impede with the clutch pedal full upward travel.

2. Adjust the clutch pedal switch as necessary.
Did you find and correct the condition?



Go to Step 16

Go to Step 4

1. Turn OFF the ignition.
2. Inspect the ECM (10A) fuse (EB-4) in the engine

room fuse block.

Is the ECM (10A) fuse (EB-4) open?



Go to Step 5

Go to Step 6



Go to Step 16



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