Isuzu KB P190. Service manual — part 292

6E-134 Engine Control System (4JH1)

DTC P0335 (Symptom Code E) (Flash Code 43)

Circuit Description
The crankshaft position (CKP) sensor is located on top
of the flywheel housing. The engine control module
(ECM) calculates the engine speed and exact position
of the crankshaft based on the signal from the CKP
sensor. If the ECM detects an engine overrun condition,
this DTC will set.
Condition for Running the DTC

• The ignition switch is ON.

Condition for Setting the DTC

• The ECM detects that the engine speed is higher

than 5700 RPM for 0.2 seconds.

Action Taken When the DTC Sets

• The ECM illuminates the malfunction indicator

lamp (MIL) when the diagnostic runs and fails.

• The ECM cuts fuel injection.

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

• Ensure the sensor is tight and the flywheel

circumference is not damaged.

Notice:

• This DTC is caused by an engine over speed

condition, which was most likely caused by driver
error (i.e. downshifting a manual transmission on a
steep grade). Ensure there are no signs of engine
damage. Excessive engine over speed may
damage internal engine components.

DTC P0335 (Symptom Code E) (Flash Code 43)

Step Action

Value(s)

Yes

No

1

Did you perform the Diagnostic System Check-
Engine Controls?



Go to Step 2

Go to Diagnostic

System Check-

Engine Controls

2

1. Install the scan tool.
2. Start the engine.
3. Observe the Engine Speed parameter with the

scan tool.

4. Accelerate the engine between idle and W.O.T.

(accelerator pedal full travel) many times while
observing the scan tool.

Does the Engine Speed parameter ever exceed the
specified value?

5000 RPM

Go to Step 4

Go to Step 3

3

Ask the driver if overrun is caused by gear slip-out,
shift error, down-slope diving, etc. If engine overrun
has experienced, the engine must be inspected and
repaired as necessary.
Did you complete the action?



Go to Step 7



4

1. Remove the crankshaft position (CKP) sensor.

Refer to CKP Sensor replacement in this section.

2. Visually inspect the CKP sensor for the following

conditions:

• For physical damage
• For being loose
• For improper installation

Did you find and correct the condition?



Go to Step 7

Go to Step 5

5

Visually inspect the flywheel circumference for
damage.
Did you find and correct the condition?



Go to Step 7

Go to Step 6

6

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 7



Engine Control System (4JH1) 6E-135

Step Action

Value(s)

Yes

No

7

1. Reconnect all previously disconnected harness

connector(s).

2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Observe the Engine Speed parameter with the

scan tool.

6. Accelerate the engine between idle and W.O.T.

(accelerator pedal full travel) many times while
observing the scan tool.

Does the Engine Speed parameter ever exceed the
specified value?

5000 RPM

Go to Step 4

Go to Step 8

8

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

OK

6E-136 Engine Control System (4JH1)

DTC P0380 (Symptom Code 4) (Flash Code 66)

Circuit Description
The engine control module (ECM) controls the glow
relay which supplies power to the glow plugs based on
engine coolant temperature. In the after glow phase, the
glow indicator light is not illuminated but glow plugs
remain active for a certain period. If the ECM detects an
open circuit or short to ground on the glow relay control
circuit, this DTC will set.
Condition for Running the DTC

• The ignition switch is ON.

Condition for Setting the DTC

• The ECM detects that the low voltage condition on

the glow relay control circuit for longer than 3
seconds when the relay is commanded OFF.

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.

Notice:

• The glow relay is commanded OFF with ignition

ON and engine OFF when the engine coolant
temperature is reached at 30°C (86°F).

• The glow relay is commanded OFF with engine

run when the engine coolant temperature is
reached at 60°C (140°F).

DTC P0380 (Symptom Code 4) (Flash Code 66)
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

No

1

Did you perform the Diagnostic System Check-
Engine Controls?



Go to Step 2

Go to Diagnostic

System Check-

Engine Controls

2

1. Install the scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Perform the Glow Relay test with the scan tool.
4. Command the Glow Relay ON with the scan tool.
Does the glow relay click when commanded ON with
the scan tool?



Go to Diagnostic

Aids

Go to Step 3

3

1. Turn OFF the ignition.
2. Replace the glow relay with the starter relay or

replace with a known good relay.

3. Turn ON the ignition, with the engine OFF.
4. Command the Glow Relay ON with the scan tool.
Does the glow relay click when commanded ON with
the scan tool?



Go to Step 12

Go to Step 4

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

5

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 16



6

1. Turn OFF the ignition.
2. Remove the glow relay.
3. Connect a test lamp between the voltage feed

circuit of the glow relay coil side (pin 2 of X-5
connector) and a known good ground.

4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?



Go to Step 7

Go to Step 9

Engine Control System (4JH1) 6E-137

Step Action

Value(s)

Yes

No

7

1. Turn OFF the ignition.
2. Connect a test lamp between the control circuit

of the glow relay (pin 3 of X-5 connector) and
battery voltage.

3. Turn ON the ignition, with the engine OFF.
Does the test lamp continuously illuminate (the test
lamp blinks then goes out normally if the engine
coolant temperature lower than 30°C [86°F])?



Go to Step 10

Go to Step 8

8

1. Keep the test lamp with connected.
2. Command the Glow Relay ON with the scan tool.
Does the test lamp illuminate when commanded ON
with the scan tool?



Go to Step 12

Go to Step 11

9

Repair the voltage feed circuit between the ECM
(10A) fuse (EB-4) and the glow relay (pin 2 of X-5
connector) for an open circuit or high resistance.
Did you complete the repair?



Go to Step 16



10

1. Test the control circuit of the glow relay between

the engine control module (ECM) (pin 94 of C-57
connector) and the glow relay (pin 3 of X-5
connector) for a short to ground.

2. Repair the circuit(s) as necessary.
Did you find and correct the condition?



Go to Step 16

Go to Step 15

11

1. Test the control circuit of the glow relay between

the ECM (pin 94 of C-57 connector) and the glow
relay (pin 3 of X-5 connector) for an open circuit
or high resistance.

2. Repair the circuit(s) as necessary.
Did you find and correct the condition?



Go to Step 16

Go to Step 13

12

1. Turn OFF the ignition.
2. Inspect for an intermittent and for poor

connections on the glow relay terminals (pins 2
and 3 of X-5 connector).

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



Go to Step 16

Go to Step 14

13

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

connection on the glow relay control circuit at the
harness connector of the ECM (pin 94 of C-57
connector).

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



Go to Step 16

Go to Step 15

14

Replace the glow relay.
Did you complete the replacement?



Go to Step 16



15

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 16

