Isuzu KB P190. Manual - part 445

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-163

DTC P0403 (Flash Code 37)

Circuit Description

The ECM controls the EGR valve opening based on the
engine running condition and by controlling the EGR
solenoid. The EGR valve position is detected by the
position sensor, and relayed to the ECM. If the ECM
detects an open circuit or short circuit on the solenoid
circuits, this DTC will set.

Condition for Running the DTC

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

Condition for Setting the DTC

Either of following condition is met:

• The ECM detects an open circuit on the EGR

solenoid circuits.

• The ECM detects a short to ground on the EGR

solenoid circuits.

• The ECM detects a short to voltage circuit on the

EGR solenoid circuits.

Action Taken When the DTC Sets

• The ECM illuminates the MIL on the second

consecutive driving cycle when the diagnostic runs
and fails. Refer to DTC Type Definitions for Action
Taken When the DTC Sets - Type B. (Euro 4
Specification)

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
(Except Euro 4 Specification)

• The ECM inhibits EGR control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type B (Euro 4
Specification)

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A. (Except Euro 4
Specification)

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P0403

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

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Monitor the DTC with a scan tool.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Diagnostic

Aids

Turn OFF the ignition.

Disconnect the EGR valve harness connector.

Turn ON the ignition, with the engine OFF.

Connect a DMM between the drive voltage
circuit (pin 4 of E-71) and a known good
ground.

Connect a DMM between the low side circuit
(pin 6 of E-71) and a known good ground.

Are both voltage readings within the specified
value?

1.4 - 1.8 volts

Go to Step 5

Go to Step 4

Is the DMM voltage more than the specified value
at Step 3?

—

Go to Step 7

Go to Step 6

6E-164 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Test the circuits between the ECM (pins 62
and 63 of E-90) and the EGR valve (pins 4
and 6 of E-71) for a short circuit each other.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 8

Test the circuits (which ever voltage reading
did not read within the specified value at Step
3) between the ECM (pins 62 and 63 of E-90)
and the EGR valve (pins 4 and 6 of E-71) for
the following conditions:

• An open circuit

• A short to ground

• A short to the position sensor low

reference circuit

• High resistance

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 9

Test the circuits (which ever voltage reading
did not read within the specified value at Step
3) between the ECM (pins 62 and 63 of E-90)
and the EGR valve (pins 4 and 6 of E-71) for a
short to battery or ignition voltage.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 11

Inspect for an intermittent and for poor
connections at the harness connector of the
EGR valve (pins 4 and 6 of E-71).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 10

Turn OFF the ignition.

Disconnect the ECM harness connector.

Inspect for an intermittent and for poor
connections at the harness connector of the
ECM (pins 62 and 63 of E-90).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 9

Replace the EGR valve. Refer to EGR Valve
Replacement.

Did you complete the replacement?

—

Go to Step 10

—

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

Did you complete the replacement?

—

Go to Step 12

—

Step

Action

Value(s)

Yes

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-165

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 13

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

6E-166 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0404 (Flash Code 45)

Circuit Description

The ECM controls the EGR valve opening based on the
engine running condition and by controlling the EGR
solenoid. The EGR valve position is detected by the
position sensor, and relayed to the ECM. If the ECM
detects a variance between the actual EGR valve
position and desired EGR valve position for a
calibrated amount of time while the EGR valve is
commanded ON, this DTC will set.

Condition for Running the DTC

• DTCs P0112, P0113, P0116, P0117, P0118,

P0405, P0406, P0652, P0653, P2227, P2228 and
P2229 are not set.

• The battery voltage is between 10 to 16 volts.

• The ignition switch is ON.

• The engine coolant temperature is between 20 to

110

°C (68 to 230 °F).

• The intake air temperature is between 0 to 110

°C

(32 to 230

°F).

• The barometric pressure is between 60 to 120 kPa

(8.7 to 17.4 psi).

• The EGR control is commanded ON.

Condition for Setting the DTC

• The ECM detects that the actual EGR position is

more than 10% below the desired position for 4
seconds.

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM limits fuel injection quantity.

• The ECM inhibits pilot injection.

• The ECM inhibits EGR control.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

• A sticking or intermittently sticking EGR valve may

set this DTC.

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P0404

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

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Monitor the DTC Information with a scan tool.

Is DTC P0403, P0405 or P0406 also set?

—

Go to Applicable

DTC

Go to Step 3

Perform the EGR Solenoid Control with a scan
tool several times.

Command the Desired EGR Position Increase
and Decrease while observing the EGR
Position.

Does the EGR Position parameter follow within the
specified value quick enough (compare with a
similar unit if available)?

± 5%

Go to Diagnostic

Aids

Go to Step 4

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